Members' Online Book: Better Offshore Motorboats, Chapter 6 of 8

A Real Sailor’s Motorboat Launched


I have written quite a bit about sailor’s motorboats and as part of that project we analyzed a very interesting boat in-build in New Zealand. That boat, the Artnautica 58, has now been launched and is in the middle of sea-trials with encouraging results.

Awesome Numbers

It’s too early in the testing process to draw firm conclusions, particularly since the interior is not complete so she is light, but four impressive things jump out at me from the initial numbers the designer sent me:

  • Top speed is over 11 knots on just 75 horsepower.
  • Fuel burn at 9 knots equates to just .88 litres for each nautical mile or a bit better than 4 miles to the US gallon. Contrast that with the average recreational trawler of similar interior volume that has hell to make 6 knots at that fuel burn.
  • Drop the speed to a bit over 7 knots and fuel burn drops to .66 litres for each nautical mile or 7 miles to the US gallon—a number that will make the boat not only far more economical than any recreational trawler out there, but also cheaper to own than just about any offshore sailboat of the same volume.
  • As the graph below shows, there is no sudden step up in fuel burn, or to put it another way, the boat is not restricted by a hull speed number, at least at these speed to length ratios.

fuel burn


second hull is already in-build, a development that makes us rather chuffed since the designer tells us that the owner of that boat was inspired to buy by reading about the design here at AAC—glad we could help with what we think is a great project.

The Future

All we need now is sane fuel pricing. With oil prices heading down this would be a great time to add a revenue neutral carbon tax for countries that don’t already have one, which would in turn lead to boats like the Artnautica 58 becoming the norm and replacing environmental disasters like this:



And here’s a video that shows how little fuss the boat makes when going through the water at 9 knots: Click Here to View


We have not received any benefit in money or in kind from the designer or builder of the Artnautica 58.

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Meet the Author


John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

68 comments … add one
  • Nicolas Jan 10, 2015, 12:13 pm

    Exciting concept albeit not a new one. For example please see with 50 hp Kubota engine completed circumnavigation and the longest passage under power for a vessel like this.

    • John Jan 10, 2015, 12:59 pm

      Hi Nicolas,

      Of course you are absolutely right, that there is nothing really new here. I thought Idelwild was way cool, but she was too extreme to general adoption.

      Talking of nothing new, I was looking at a book of designs from the early 20th century, which had several examples of boats like this.

      However, all those boats were custom. The Artnautica is an attempt to create a production boat with general appeal at a relatively reasonable price.

  • Nicolas Jan 10, 2015, 2:25 pm


    I agree Idelwild was a bit extreme for general adoption e.g very narrow beam when compared to Artnautica but similar displacement number.
    What worries me though is the manufacturer range claims (not particular for Artnautica) but for every long range power. When these are checked against real world fuel consumption/range values as given in various passagemaking under power publications (Leishman and Utmost) or in passsagemakers’ accounts one finds huge differences. Of course this is to be expected (weather such as wind, sea state parameters are induced as well as hull/prop fouling, loading conditions etc). I know this seems obvious but it nevertheless has to be conveyed to the average prospective customer who is probably inexperienced and not well informed.

    Another issue that bothers me is the lack of continuous duty rated engines for relatively low powered marine engines (although the kubota seemed to have faired well). I would not like to venture far offshore with a high revving, small displacement engine without sails, even I have to pay a premium for them and never use them.

    • Matt Jan 10, 2015, 7:06 pm

      Re. small industrial-duty engines.
      I’m hesitant to recommend a “continuous duty” rated engine for motor yachts of the type we’re discussing here.
      Why? usually, a particular engine will be offered in a few different ratings. There might be a 60 hp “continuous duty” version, 80 hp “commercial duty” versions, and a 100 hp “pleasure craft / light duty” version. The 60 hp is tuned to run at one speed, not much more or less. The 80 hp and 100 hp versions give up a little bit of fuel efficiency at that one speed, in favour of a wider operating range and some extra headroom at the top end.
      If you run the 80 hp version at 3/4 throttle, it’ll last about as long and burn only a bit more fuel than the 60 hp version at its continuous WOT rating. But now you have the extra power available for when you have to beat off a lee shore.

      • Nicolas Jan 11, 2015, 3:24 am

        At this power range < 100 hp all of the now available marine diesel engines (except Bukh-max 48 hp, and air-cooled Deutz) are rated around 40% continuous (Nanni, Yanmar, 2-2.2 litres cylinder displacement pleasure and the like) and somewhat more for more commercial models such as 4 cylinder Yanmar -commercial, Perkins, John Deere M2, with displacement around 4 litres. Even running at 3/4 loading can be against the manufacturers specifications. Most manufactures at these ratings recommend full loading 1/12 hours operation or less.
        These engines are not designed for serious ocean passagemaking under power and are mostly used as auxiliaries in sailboats.

        • Laurent Jan 11, 2015, 10:32 am

          Small diesel engines are fairly mature today, and the classic old way of building them is to use: iron block, wet liners, 2 valves cylinders heads and a limited number of cylinders (1 to 4….).
          Point is that it doesn’t give a very good power/weight ratio, and a limited power/weight ratio is not good for performances and also not good for cost, because manufacturers need to fabricate more steelwork or assimilate for any given power.
          You can increase power/weight ratio using dry liners or no liner, aluminium blocks (with or without liners…), 4 valves per cylinder and more than 4 cylinders.
          A serious long-range small aux. sailboat or limited-power motorboat engine should have: wet liners, 2 valves per cylinder an no more than 4 cylinders. Those engines are bulkier and heavier than more “modern” ones of same power, but they are often cheaper, because corresponding market are more competitive and product life-time are longer.

        • Eric Klem Jan 11, 2015, 1:37 pm

          First, I think that this certainly looks like a very cool boat and I am interested to hear how it does in the real world. I can’t see myself in a motorboat right now as I really enjoy the act of sailing but maybe someday.

          On the subject of engines, continuous versus intermittent ratings are really about heat management. In an engine, 10^6 stress cycles will often be hit in a single day of running so fatigue due to cylinder pressure is really not a concern as everything is designed for an infinite fatigue life. As Matt points out, you often see the same engine with different power output ratings and the higher ratings become intermittent because of heat management issues. The rating will typically state a maximum amount of time that the engine can be run at a condition and this will be less than the amount of time to reach steady state temperature. When picking an engine, it is up to the designer to make sure that the maximum continuous output meets the requirements of their design. Having an extra bit of power for occasional use can be nice and is often almost free for the designer to add by simply picking a higher output version of the same basic engine although the user needs to be careful about how they use this extra power.

          What really matters to the user is how reliable and long lived the engine is. Realistically, engines are usually replaced because they are very old with hard to find parts or they have poor compression. Ring wear on an engine can best be approximated by a pressure velocity (note that this is velocity and not rpm as high revving engines can have low velocity if the stroke is small) relationship. Transient states are also really problematic so frequent cold starting is not a good thing. Laurent mentioned the switch from a single intake and exhaust valve per cylinder to multiple and there are a few very good reasons for these changes. As engines rev higher, you need to have greater valve area to keep your valve losses down and you also need to have them open and close more quickly which drives you to multiple smaller, lower lift valves. A large driver of the increase in number of valves and fancy injection systems is emissions regulations. As much as I don’t like a lot of the complexity of modern engines, they are remarkably reliable.

          I have no problem with using a higher output spec of a given engine provided that the designer used the continuous rating in their calculations and made the user aware of this.


          • Laurent Jan 11, 2015, 2:49 pm

            There is no magic in diesel engine design. To get reliable, engines you need to:
            – Limit the number of parts : with same mechanical & thermal constrain the probability that any given component fails is identical. So the probability of valve failure with a 4 cyl. 2 valves/cyl. engine is 1/3rd of same probability with a 6 cyl. 4 valves/cyl. (24 valves instead of 8…).
            – Use wet liners : liners allow the use of more adapted steel for cylinder walls than the steel (or alloy…) used for the block. Wet liners allow a much more even temperature distribution in cylinders.

            I understand that knowledgeable diesel-engine developers know those recipes very well, so why don’t they apply them more often?. Main reason is that engine-blocks development is very expensive and manufacturers need to develop engine blocks for a wide range of uses. Diesels for long-range boats in the 30 to 100hp range are not large enough as a market to justify the development of engine-blocks precisely adapted to those requirements (4 cyl. 8 valves, wet liner….) . In practice, most engine-block used on this market were developed for mobile application, (light trucks, mobile gen-set etc…) where reliability requirements are lower and weight requirements are higher, which means dry liners, 4 valves per cyl etc…
            So at the end you might have to chose between old and heavy “low-cost” blocks with the most appropriate architecture, but a bit on the cheap side on the market, which might ask question about manufacturing quality (for instance Kubota…), or more modern first-brand blocks, whose manufacturing is supposed to be better, but who are more adapted to building equipment or light trucks than to long-range boat, and whose architecture is clearly not as good for this market (4 valves/cyl. dry liner etc…). Personally I tend to prefer the simpler old-fashioned solution, but I agree that, for reliability, manufacturing quality is sometime more important than having the most appropriate architecture.
            Piston’s velocity relates to engine life-expectancy more than to reliability.

      • John Jan 11, 2015, 2:15 pm

        Hi Matt, Eric and Laurent,

        Really interesting stuff on engine ratings, thank you.

        A question: what is the effect on all of this of using a Controllable Pitch Propeller?

        Dennis just sent me an email relating that he had just completed a run north to the Bay of Islands running the engine at just 1400 RPM , but doing 10 knots and burning less that a litre/mile! He did have a ten knot tail wind. He cranked in enough pitch so the exhaust temp was at the maximum recommended by Beta Marine (400c).

        It is totally amazing to me that he could reach that speed at that RPM and keep it up for hours—the wonders of CPPs.

        So my questions are:

        1). Is he, by running this way, increasing, decreasing, or having no appreciable effect on the life of his engine?

        2). With this usage profile (light slippery boat and CPP) would he be better off with an M1, M2, or M3 rated engine, assuming that Beta would give him the option.

        • Eric Klem Jan 11, 2015, 3:59 pm

          Hi John,

          Definitely interesting questions and I don’t think that I have enough design information about the specific engine to give a full answer. Dennis has definitely started right by installing an EGT gauge. For the user, this one gauge usually tells you more about engine load than anything else. It is important to note that sensor placement is really important, especially on turbocharged engines which can see 300F temperature drops through the turbo. If he also has an inline fuel flow sensor, that would be very powerful for fine tuning as well.

          400C is a relatively low EGT provided that the pistons are not aluminum. A lot of big engines have limits around 500C. Over the road trucks often see values of 600C+ and sled pullers will see short burst of 900C+. It is worth noting that the limits are very engine specific. A lot of people would refer to this type of operation as lugging but I don’t think that this is totally fair. The fuel map for the engine should be set in such a way that it has a fairly constant maximum cylinder pressure across the rpm range so mechanical loads should be equivalent to running quite hard at high rpm. In very extreme cases, people can damage plain bearings (colloquially bushings) with high loads at low rpm because they can’t carry as high loads at low speeds but I don’t expect that this would be a concern. Ring wear should not be a big concern because the velocity will be low even though the pressure will be high. Typically the real problem with running low rpm is EGT because you need to burn more fuel on each combustion stroke but he is monitoring that.

          Regarding engine ratings, I suspect that the calculated load factor is still low with this type of operation compared to the M1 type service of tankers, etc. Based on the numbers in your comment and a max fuel burn of 16L/hr for a Beta 75, the load factor would be <60% which is in the realm of M2. Realistically, we would all want to have M1 rated engines but for the same power they tend to be heavier and larger so the designer needs to make trade-offs. A higher load factor will simply wear out the engine more quickly. Probably the best indicator of engine life for any given model is simply the volume of fuel burned.


          • John Jan 12, 2015, 1:46 pm

            Hi Eric,

            Yes, he does have an inline fuel sensor.

            Thanks very much for the clear explanation, as usual with you and Matt’s answers, I learned a lot.

            One follow up question. Is there a single ETG max temp for an engine, or does that vary with RPM?

          • Marc Dacey Jan 13, 2015, 1:09 pm

            Interesting information on the utility of EGTs, one of which I was considering installing, as well as a water flow sensor for safety reasons. I gather that with an EGT in the mix, I could refine the pitch of my four-bladed feathering prop for maximum fuel efficiency, which in an ocean-crossing sailboat is of more import than raw speed, as the engine won’t be on if I can sail at three knots. Thanks for this discussion: I nearly didn’t read it because “motorboats”…but I should keep an open mind!

          • Eric Klem Jan 13, 2015, 4:32 pm

            Hi John,

            I have never heard of people using more than a single EGT number for any given engine although most of the engines that I know of which run one are fairly constant speed or high performance. There is no such thing as an exact EGT number at which things become unsafe as the safe level is affected slightly by several factors one of them being RPM so you just need to pick a conservative number.


        • Matt Jan 11, 2015, 6:43 pm

          A CPP, if used correctly, lets you keep the engine at the optimum combination of RPM and torque for the desired power output. This eliminates the problem inherent to fixed props, where the engine is underloaded (running at higher RPM and lower torque than ideal) through much of the operating range. Used correctly, the CPP should result in less fuel burn and longer engine life.
          As has been pointed out, you need the EGT (exhaust gas temperature) sensor, the engine manufacturer’s EGT specifications, and the knowledge of how to set the CPP correctly. Get it wrong and you can do some expensive damage by overloading the engine.
          (Teaser: CPPs are in the “draft articles coming soon” queue…)

          • Svein Lamark Jan 12, 2015, 8:10 am

            I guess a perfect engine to this long distance ship is the Grenaa diesel type 3F24 slow speed. Look at This engine is cheap to buy and to use. It has a CPP at “only” 130 cm diameter. First inspection service is at 5000 hours and at 50 000 hours. First main service at 150 000 hours. 3 separate fuel pumps with crude oil ability (dirty diesel is no problem). Max output at 500 RPM is 165 HP. At 310 RPM it will probably give this ship 8,5 knots at 5-7 litres. The sound of this very quiet engine is wonderful. I inspected the factory recently, quality is superb and they have plenty of spare parts. The quality of this small diesel engine is far above anything else on the marked today and the people on the factory are very kind and charming. The only negative argument I can think of on this engine is the weight. It is much lighter then my Callesen engine, but still many kilos.

          • John Jan 12, 2015, 1:22 pm

            Hi Svein,

            That’s interesting. How incredible it would be to have an engine with a 50,000 hr service interval!

            However, I’m guessing that, as you say, the weight would be too much for the Artnautica hull form.

          • Laurent Jan 12, 2015, 8:26 am

            Point is that, reading Grenaa Internet site, it looks like their current engine offering starts at 450hp, which is excessive for most sailboats’ aux. engines and/or most Dashew or Artnautica type motorboats.
            I guess there is a market for those kind of engines in the 40 to 200hp range, but probably not large enough to justify the development of new engine blocks. And, of course, there is no engine block currently in production that could be used for that.

          • John Jan 12, 2015, 1:29 pm

            Hi Matt,

            I’m really looking forward to your CPP article. I’m convinced that we must look to better technology to more efficiently balance torque and load like CPPs and maybe variable transmissions instead of wasting time with diesel/electric with it’s inherent conversion inefficiencies. The more people that understand how a CPP works, the more likely we will pursue it.

            (A sensible carbon tax would go a long way to encourage such efforts too.)

          • Laurent Jan 12, 2015, 2:25 pm

            CPP and diesel-electric transmissions have been used for ages on many different kind of ships.
            Current result is a very clear win for diesel-electrics, which are much more frequents on existing full-size ships than CPP (most large passenger-ships, quite a few recent military ships etc…..).
            The only issue for much smaller sailing or motor boats, was the unavailability of very efficient (92%+…) electric generators & motors appropriate for that kind of use. This point is evolving very fast those days, because of the electric cars & light trucks market. Perhaps this technical fact is not pleasing many people in the boating industry….

  • Matt Jan 10, 2015, 7:12 pm

    This is really cool!
    I am very curious to see how the numbers look once she’s fully loaded down, and also how the hull handles when the sea state picks up. So far, it sounds like the performance predictions were pretty close to on target. And… virtually no wake! Very slick.

  • Niels Jan 11, 2015, 10:56 am

    Is it me or is there more than a striking resemblance to Dashew’s Wind Horse?

    • John Jan 11, 2015, 12:00 pm

      Hi Niels,

      You are right that there is a superficial resemblance to Steve Dashew’s boats, but it is only just that, superficial. The hull form of the Artnautica is a very different. If she had the same hull form as Steve’s boats she would weigh at least double what she does and the price would go up by the same factor. You can read more about this in Matt’s excellent review of the hull form.

      • Jean-François EEMAN Jan 12, 2015, 12:59 pm

        Hi Niels,
        Hi John,

        I do agree with John…
        Moreover the logic of the boats seem very different to me.
        I would say that the logic of the Artnautic is one of simplicity and close to a sailors’ mentality/spirit… Steve Dashews’ boats seem from what I have seen much more into luxury, same equipment and complexity as on most of the trawlers. Or am I perceiving this in a wrong way.

        • John Jan 12, 2015, 1:18 pm

          Hi Jean-François,

          I think that’s a perfect analysis.

          Further, I’m guessing that Denis’s (Artnautica Designer) biggest problem is going to be explaining exactly that to people who want to know why it is not loaded up with all the creature comforts and forget that by forgoing all that stuff they have a boat that will make it from Newport to Bermuda in 60 hours while costing her crew less than flying the same distance—kind of the same challenges we have explaining the Adventure 40.

  • Simon Wirth Jan 11, 2015, 11:28 am

    No, the resemblance is there. Also the wake shows some similaritys, not too astonishing, I think.
    Will be interesting to see how the numbers compare, even if they aren’t exactly in the same range.

  • Svein Lamark Jan 11, 2015, 2:47 pm

    Hi John!
    I know many trawlers that can sail 7 knots consuming 5 litres of fuel pr hour. My old boat from 1951 does it with a slow turning four-stroke Callesen diesel. It has no gear box and a large controllable pitch propeller. The Callesen consumes 150 grams/hour/ HP. Modern diesels have a problem to get below 200 grams. At only 7 knots the friction is low also with a traditional hull. It is when you increase the speed above 7 knots a modern hull is much better. Modern boats have often an inefficient engine, inefficient gear box and drivetrain as well as a too small propeller. I have seen modern trawlers with high speed engine, gear box with reduction up to 12 and propellers up to 3 m in diameter. At low speeds this trawlers are consuming little fuel, but they are very bulky and not fast. It is not only the hull shape that makes influence on fuel consumption, it is also the efficiency of the hole engine system. Do you have any data on engine, gear box and propeller on this boat?

  • Svein Lamark Jan 12, 2015, 10:05 am

    Hi Laurent, you have misunderstood the Grenaa diesel production. Grenaa still produce the small 3 cylinder engine at 165 HP. Please go to page showing the slow speed and not the medium speed type. You can get the slow speed engine without turbo or compressor. A friend of mine bought one a few years ago to his boat of 45 ft. It is like sailing a steam boat.
    The main production of engines at Grenaa is medium speed diesels, but most of the production is concentrated on wind mills. Slow speed diesels are a little part of the production to day, but the workers and their leaders seem to love their slow speed engines.

  • Jon Valen-Sendstad Jan 12, 2015, 7:36 pm

    came across another interesting yachtdesigner:
    probably known to you allready.


    • John Jan 13, 2015, 12:28 pm

      Hi Jon,

      Yes, I have written about Steve and Linda Dashew several times. Great boats, but they are very large and start at around the 3 million dollar mark, so only applicable to those with very deep pockets.

  • Ron Berger Jan 13, 2015, 11:19 am

    Burning any fossil fuel at all as a primary mode of propulsion is unconscionable for a boat in 2015. Except for the blind among us, we boaters must have seen the deplorable state of the world ocean. Only monstrous arrogance could lead us to further contribute to it.

    There is an alternative: use the wind, and only the wind. Leave your engine off except to get into or out of the wind at the extremities of a voyage. Accept that we have done massive and possibly intractable harm to this planet and dare to stop. Put our egomaniacal schedule aside and only travel when the wind allows it. Walk lightly on the face of the planet.

    • John Jan 13, 2015, 12:37 pm

      Hi Ron,

      A laudable sentiment, I’m sure. But perhaps not a very practical one. My thinking on ways to actually make a meaningful reduction in oil use and carbon production are here and I think that a boat like the Artnautica can be part of that process.

      More on the same subject here.

  • BrianC Jan 13, 2015, 3:21 pm

    I really like the general design and philosophy behind the Artnautica LRC 58 – but I wonder about a few details.

    1. First of all – is it my imagination, or does the design have a lot less interior volume that the Dashew FPB design. I look at the interior layout of the FPB 64 and it has room for 6 people comfortably – and it looks like the Artnautica really is designed for 2 people (with possibility of 2 additional in front – I’ve seen in some designs:

    2. Secondly – generally I think Dennis has more boat design experience and training than Dashew but obviously Dashew has much more long range cruising experience than Dennis has (which I believe is very little). The hull design of the Dashew FPB is much narrower at the stern, and I remember from reading the blog entries that Steve did this because I believe he says the narrower stern causes fewer issues in large waves – where the broader beam of a wide stern will tend to push the nose down, and also causes more “tail slap”. I think I recall Steve saying that the more traditional designs today are all wider stern designs. I’m wondering what the rationale for the wider stern designs are – other than just added space.

    3. I’m wondering about “get home” power. I’m wondering if get-home sail is an option, as has been designed into the FPB 64? I’m also very interested in Kite designs for get-home power – as has been experimented with in Europe. Any news or thoughts on this?

    4. Larger Windows. One of the key reasons I would move over to power from sail is the larger windows that can make the daily experience of travel on water much more enjoyable. I like the larger windows of the Dashew designs, and also of the Gunboat series
    Do you think that the design could be altered to have larger windows more like these designs? I think Dennis is undervaluing the benefits of these larger window designs.

    5. Flying Bridge – From my own experience, and from what Dashew says in his blog – they spend most of their time in the Flying Bridge. Is there any problem with the Artnautica design in terms of its ability to support a flying bridge design?

    Any input greatly appreciated on these issues.

    • John Jan 13, 2015, 8:06 pm

      Hi Brian,

      I don’t think that approaching the Artnautica by comparing it to Steve’s design is really the way to go if for no other reason that the FPB 64 is 5 times more expensive and three times bigger (boat size is measured by weight, not length).

      The key to appreciating the Artnautica is to embrace it’s elegant simplicity and not try and turn it into a trawler with lot’s of features—kind of like the Adventure 40.

      Dennis did tell me that get home power would be possible, but he is looking into kites and will be filling me in on that.

      As to the stern sections, yes, the Artnautica is a very different hull form from Steve’s boat, it has to be, or it would weigh 3 times more than it does. It remains to be seen how the boat will work out in big seas, but my guess is that she should work out well and be seaworthy.

      You might want to read Matt’s analysis of the design here.

      • BrianC Jan 13, 2015, 9:47 pm

        Hi John,

        I appreciate that the Dashew FPB 64 is a different boat than the LRC58, but it seems that there are some good features of the FPB design that could be very helpful on the LRC. Also – correct me if I’m wrong – isn’t another way to measure “bigness” of a boat – the internal volume of the boat? While I know that FPBs are made of much heavier scantlings and much thicker aluminum – so they are going to weight a lot more – but the interior volume (especially if you scale the LRC up to 64 feet) should be relatively similar – shouldn’t it?

        Also – since I know that Dennis views his first boat as a prototype – I’m looking at ways to get many other opinions, including my own – on how to improve it. So – when in couple of years when I’m thinking I’ll be in the market for such a boat – it will more likely be something that aligns more closely to what I’d like.

        Given the prototype nature of this first LRC that Dennis has produced – my suggestions (above) are areas of improvement.

        Do you disagree with these areas of improvement?

        I do a lot of cruising along the British Columbia coastline in the summer – and the weather is considerable better than for you out on the East Coast. Because of this – I want bigger windows and a good flying bridge. Also – generally I see these factors as being very beneficial on global cruising – and don’t seem to negatively impact the “simple is better” model of the design.

        • John Jan 14, 2015, 11:56 am

          Hi Brian,

          On volume, no the volume would not be the same as the FPB 64 if you made the Artnautica 64-feet, I would guess the latter would be about half the weight and volume as the former if both were the same length.

          The reasons for this are complex, but basically if you increase volume, you also increase wetted surface and displacement, which then requires a bigger engine to make the same speed…which needs more fuel to make the same range…which makes the boat heavier with more wetted surface…which requires a bigger engine…and on it goes. And of course, if you add volume then you are going to fill that volume with stuff, which makes the problem even worse.

          The bottom line is that the Artnautica is about 1/3 the size of the FPB 64, and nothing can change that fact. Make the boat bigger to get more volume and the price will go up, at least by the same proportion as the increase in displacement, probably more.

          As to your suggestions. I can certainly see why you would want those features, although I would not. But you can’t just add such things to an existing boat, design is holistic. Let’s look at the flying bridge:

          Adding it, will adversely affect stability, so the boat will need to be made heavier and/or wider to compensate. But wait, wider will adversely affect self righting capability. Oh yes, and the added weight of the flying bridge will require a stronger wheelhouse structure to support it. But wait, you want bigger windows, that means a higher wheelhouse…oops, stability goes down again. Bigger windows…oops, we need more wheelhouse structure. Now the boat is a lot heavier…and we need a bigger engine…and on it goes.

  • Svein Lamark Jan 13, 2015, 3:57 pm

    Hi John!
    The weight of a Grenaa 3F24 165 hp is around 5000 kg. I do not know if that is too much for the 58 ft Artnautica?
    I do agree with your comment to Ron, but of course we should all of us try to reduce pollution to a minimum. That is way I advocate slow speed diesels. A slow speed diesel uses less fuel than high speed engines and the outlet of nitrogen oxides and hydro-carbones are low. In some countries this is rewarded by the right to buy fuel excl. pollution related taxes. The manual of my Callesen diesel (same HP but 10 000 kg) says : “If you see any smoke in the exhaust, stop immediately. Your engine has a serious problem”. However my modern high speed diesel is always smoking.
    And with a slow speed engine, you can leave the maintenance to the next generation of owners. My Callesen has passed 120 000 hours and we have done almost nothing. A fresh compression test says it is still young.

    • BrianC Jan 13, 2015, 4:15 pm

      IS that a typo / mistake – does the the Grenaa 3F24 really weigh 5000Kg?

      The engine that Dennis has chosen for the Artnautica 58 LRC is the 400 Kg Beta Marin 75 – details here:

      Does anyone have an opinion on this engine?

    • Eric Klem Jan 13, 2015, 4:45 pm

      Hi Svein,

      My apologies if I missed this somewhere else. Is your boat recreational only or does it do any commercial work? 120,000 hours is a really impressive number of hours (~14 years continuous!) even for an older boat. I wish I was underway that much.


  • Svein Lamark Jan 13, 2015, 7:23 pm

    Hi Brian, yes you are reading correct. A slow speed diesel is heavy, but the Grenaa is the light weight version of the slow speeders.
    Hi Eric, you are also reading correct. My Callesen boat has mostly been fishing professional from Poland to Greenland, but most of the time in The North Sea without me aboard. Because it is so old and charming it is now a nice museum as a yacht. I have had three other small fishing boats that all passed 500 000 nautical miles, but mostly I was ashore in the office. I have also sailed many large fishing boats world wide. My little sailboat has though made 240 000 miles with me.
    The only problem with a very old engine like the Callesen is that spare parts are getting rare. On the other hand Grenaa has plenty of spare parts and because of their windmill production they are doing well. If my old Callesen stops I will get a Grenaa. I think modern diesels are crap and making too much pollution.
    For your information: I have no economic interest neither in Callesen nor in Grenaa.

    • Eric Klem Jan 13, 2015, 11:02 pm

      Hi Svein,

      Very interesting. That certainly explains the high hours. Those old fishing boats can be really neat. When I was designing industrial machinery (compressors and steam expanders), we tried to design for a 40,000 hour overhaul. Depending on the application, it was sometimes acceptable to do a ring type service every 8,000 hours but we generally tried to just go for 40,000 (5 years). Designing the housings and rotating parts was easy, bearings took some thought but weren’t too bad but the trick was always the seals. In certain applications where controlled leakage was allowed, we could labrynth seals which effectively have an infinite life but if we had to design a tight machine with lip seals or even carbon rings, that was tough.

      I hope that I haven’t taken the comments too far off track.


      • John Jan 14, 2015, 12:00 pm

        Hi Eric,

        No worries on going off track, I, for one, am finding the discussion fascinating.

  • BrianC Jan 14, 2015, 2:40 am


    Just a few more comments and questions about the LRC 58 and your understanding if it.

    How comfortable are you with the designed-in safety features of the boat for higher latitudes cruising? How does it compare to the Adventure 40 in terms of designed-in safety? Does it have water-tight bulkheads fore and aft? How does the design compare to the Ovni class of boats in terms of safety features and suitability for higher latitude cruising?

    Also, I would feel a lot more comfortable with the boat if it was being manufactured by a company experienced with building off-shore long range boats – for example if the boat was built in the same yard as the Alubat boats.

    Given that these boats are never going to be produced in a mass scale – (and given my experience in manufacturing) I think that if you want to get down the learning curve at all (so that these boats are not just a series of customs boats built by a lot of different independent aluminum fabrication companies) you really need to have the manufacturing concentrated in 1 or two companies – ideally ones with a lot of experience in building off-shore boats, so that the production team isn’t learning all the issues on Your boat.

    Do you feel that this is likely to happen?

    • John Jan 14, 2015, 11:40 am

      Hi Brian,

      All good points, and valid worries that I share. The 1000 lb gorilla in the room is: (as you say) is she seaworthy in extreme conditions? And if so, how would one handle a survival storm offshore in the boat? I have some ideas on both counts, but still have a lot of analysis and discussion with the designer (Denis) to do before I can come up with any sort of opinion on these issues.

      Phyllis and I are considering a trip to NZ next winter (my mother was a Kiwi and I love the country). If so, we will investigate these points, and others, exhaustively.

      In the meantime Dennis is being very open with us about the results of sea trials, so as we get more data we will report.

      And I agree completely about what needs to happen in manufacturing. Having said that the company building the second boat seems to be experienced with aluminium and well regarded.

  • BrianC Jan 16, 2015, 7:22 pm

    Just to add a little more commentary / discussion around what might be some improvements in the Artnautica Design…

    When you look at the FPB 64 design from the side (here):

    you can see that the fly bridge that Dashew has implemented is very minimal in terms of mass – so I believe that something like this could be accommodated in the LRC 58 design without much impact on the over-all design.

    I also question the decision to design the rear of the boat with that large open space that has the floor at close to sea level. Many other boats have the rear deck area at the same level as the fore-deck area – and with the benefit of additional space below decks. I’m not sure what the design of the LRC 58 is below the floor of the aft-deck, and the cabin, but perhaps a raised aft deck would provide some valuable storage space for longer trips.

    Like you – I would also like a larger cabin area – at least another set of windows/cabin area that would extend back towards the stern of the boat.

    The FPB series is also leveraging a newly designed bolt-on rear swim step that doesn’t “officially” add into the length of the boat for regulation purposes. So – something like that would dovetail well with a raised rear deck design. From what Dennis has described in terms of refrigeration space, etc. – it seems like the design might be limited in its ability to store food for a longer range trip.

    Dennis has mentioned using the dual poles for “flopper stoppers” – which is fine when at a standstill, but its not entirely clear to me if he’s also thinking of using the polls for Paravanes (for stability during travel). Do you know the answer to this?

    I hope you can provide some influence in Dennis’ plans regarding manufacturing – because if this boat design is to hold its value and not just be plans for a series of custom boats – then he really needs to leverage the experience of an aluminum boat manufacturer that has some significant experience with long range boats in the 40 to 80 foot range. I know I would feel much more comfortable buying a boat made by Alubat than by one of the hundreds of aluminum boat building shops that do a lot of custom boats and industrial boats. I have to believe that some of these shops that build the leading sailboats might be interested in working with a powerboat designer to help fill up their capacity in their shops.

    Also – if a boat was built in the same shop as, say the Ovni boats, it would definitely help in resale value.

    Lastly – what do you think of the current length of 58 feet for the LRC? I’ve read in Dashew’s blog that a natural cut-off point for these types of boats is 65 feet because longer than that the rules change. Why wouldn’t Dennis just design it for 65 feet.

    Do you think he’s just optimizing the design for a traveling couple – and so if you go for a longer design, you’re really talking about another use case (e.g. two couples long term, or a larger family of 4 to 6 people longer term?

  • John Jan 17, 2015, 1:06 pm

    Hi Brian,

    As I have said before, I don’t think couching the discussion by comparing the two boats is constructive, they are just too different. If you want a Dashew 64, the best thing to do is buy a Dashew 64, not try and turn the Artnautica into said boat.

    The Artnautica excels speed, economy, and price wise because it is a light simple boat. If you try to turn it into something else, it just will not work well at anything. Good boat design in holistic, it simply does not work well to take a bit from here and a bit from there, and stick them together.

    Having said that, the second boat has the cabin extended back one more frame and I agree that it would be interesting to look at dispensing with the cockpit in favour of flush deck. However, you would not be able to fill all that additional space with accommodation and stuff without wrecking the trim and making the boat pound. Also, this will leave you with the problem of what to do about a dinghy. I have some ideas about that, but will save them for the next article on the boat.

    Also, the boat, as designed, has an integral swim platform already.

    I will be writing more about the boat in the future and will look forward to discussing it in more detail then. In the mean time I think we should leave it there.

  • RDE Jan 17, 2015, 11:17 pm

    I must say that the concept of a narrow 58′ ULDB motorboat weighing only 12 tons with very narrow entry transitioning into broad flat stern sections doesn’t strike me as correct for a long distance ocean cruiser. I’ll reserve judgement for now, but bear in mind that this is a radically different hull form from Steve Dashew’s designs which have proven themselves over hundreds of thousands of sea miles. And that is apart from the issue of what it would cost to manufacture such a boat in series production, and whether it would find any buyers at all at that price.

    As to the wake generation touted in the video, my old Cape Gorge 36 with a hull form designed in 1942, with a 32′ waterline and weighing 23,000# (nearly as much as the Artnautica) produced absolutely no wake when driven to the same percentage of theoretical hull speed. It was powered by a little 18 hp BHUK with an inefficient 2 blade fixed prop hidden behind a massive amount of keel deadwood. I doubt if the delivered thrust was over 10HP when motoring at a speed scale equivalent to Artnautica as shown in the video.

    • John Jan 18, 2015, 12:29 pm

      Hi Richard,

      Good points, and I too wonder if the boat will end up being ocean capable. Having said that, the early indications that I’m getting from Denis do seem to be encouraging.

      Also, even if the boat does not turn out to be ocean capable, I still think it would make a fun coastal cruiser and that 10 knot speed on substantially less than a litre a mile is compelling.

      As you say, Steve’s hull form is proven, but as Steve himself has told me, that hull form requires a certain minimum size and weight to work, and weight=money.

      • RDE Jan 18, 2015, 1:15 pm

        Hi John,
        It is a mistake to conclude that weight=money in any linear sense. More correctly, ultralight + durable = expensive!

        The Artnautica hull form is narrow and light, but I wouldn’t consider it particularly efficient at moving 12 tons through the water— not in comparison to the 1942 Atkins design I described.

        For the coastal cruiser mission the 50′ Hughes catamaran power boat we have discussed is far more efficient, with equal low speed fuel economy, substantially higher speed at economical fuel burn rates, unsinkable floatation, and and twice the accommodation in a much more user friendly layout. And it is based upon literally hundreds of thousands of hours of daily use by predecessors.

        Because of its design attention to efficient build techniques, I believe it can be built either as a custom or production boat for less than the 58′ aluminum Artnautica design.

        • John Jan 18, 2015, 1:37 pm

          Hi Richard,

          I hear you on the cat, but as we have discussed before, the problem is that that boat simply does not exist in a form that the average person can buy. If it ever does, I will be happy to give it big time exposure here…there you go, stop skiing and start building!

  • RDE Jan 18, 2015, 4:16 pm

    Hi John,
    The reason I live on rice and beans (with an occasional elk steak) is because I spent too many years as a boatbuilder so I’ll pass on your suggestion! Neither the Artnautica or Cat Tracks are mass produced boats nor are they likely to become such because they deviate so far from the accepted fashions. Both have only two or three examples under construction. How well they fulfill their quite different design missions remains to be seen, but I would point out that the narrow hulled pure displacement catamaran has a far greater proven design and service history behind it.

    If someone wants a new production powerboat they will have to settle for one of the wallowing trawler tubs, a fuel gobbling planing motor yacht, or one of the worst-of-all-possible-worlds catamaran trawlers. But she will be great fun while partying at the dock.

  • Wilson Fitt Jan 28, 2015, 6:19 pm

    I admire the new class of vessels like Artnautica and the Dashew examples for their uncompromising pursuit of the assigned mission, but as Hervey Garrett Smith said so eloquently:

    “It is not enough that a yacht should be weatherly, smart, and efficient. She should be beautiful and appealing, not to the eye alone but to the heart as well.”

    I find the ruler straight sheerlines, brutally upright deckhouses and the anchor handling probosci hard to look at, let alone admire for their undisputed functionality. Anyone who knows my boat would be quick to say that I strayed too far in the other direction and significantly compromised function for looks, but it takes all kinds …

  • RDE Jan 30, 2015, 11:57 pm

    re easily driven hull forms:
    This video provides an interesting comparison to the video clip in he article about Artnautica.

    Holo Holo has about the same waterline length and over twice the displacement (she carries up to 70 passengers) but is a round bottomed pure displacement hull form only about 5’6″‘ on the waterline beam. Half as wide for a similar displacement per hull.

    Two hulls instead of one, but focus upon the comparative wake propagation of a single hull. Artnautica produces a moderate stern wave cresting about ten feet aft of the full beam flat stern hull section. Holo Holo leaves a long trail of white water behind each hull but the total wake height is about the same as Artnautica.

    One small detail—– Holo Holo is running at close to 30 knots starting at 52 seconds in the video— three times as fast as Artnautica and approximately 2.5 X theoretical hull speed! That is efficiency! And even more so when you slow down to 12-15 knots.

  • sailortodd Mar 4, 2015, 3:32 pm

    Hi John,

    I wanted to point out that the Artnautica 58 is much more akin to Kelly Archer’s “Ripple” than to the Dashew FPB. Take a look at the following link, a design concept that Kelly came up with over 10 years ago:

    I won’t wade into the pro’s/con’s, but both designs above vary significantly the Dashew FPB’s.

    Todd Rickard
    FPB Yachts

    • John Mar 5, 2015, 8:24 am

      Hi Todd,

      Yes, very good point that the resemblance between the FPBs and the Artnautica are purely superficial. I was email-chatting with Dennis (Artnatica designer) and he said that maybe people would not make the mistake of assuming that the two boats were similar if he just painted his!

      Interesting link to Kelly’s boat, thank you.

  • Henry Oct 1, 2015, 3:27 pm

    Second LRC58 has been launched by Dickey.
    Looking forward to more information and photos.

  • Henry Oct 7, 2015, 6:26 am

    Stern and interior pics of the LRC58 are now available (click on LHS arrowhead to scroll thru):

    • John Oct 7, 2015, 7:07 am

      Hi Henry,

      Thanks, exciting stuff! I will be writing more about the LRC58 later in the year.

      • Henry Oct 7, 2015, 4:51 pm

        It would be interesting to see pics of the engine room and the build along with sea testing data.

        • John Oct 8, 2015, 6:36 pm

          Hi Henry,

          Me too. I will see what I can get from Dennis. He has been incredible forthcoming to date, so I’m sure we will be able to get some good information to publish later in the year.

  • Henry Oct 7, 2015, 6:35 am

    Sorry link in previous post did not work as expected.
    Try this one:

    Click on images as required.

    Also try this one:

    Click on images as required.

  • Henry Oct 18, 2015, 7:04 pm
  • Henry Oct 28, 2015, 8:49 am

    Dennis Harjamaa has provided the following link on his Facebook page:

  • Henry Jun 20, 2016, 7:10 am
  • Henry Jun 23, 2016, 8:50 am

    Dennis has linked to the Domino website which provides some comments on the LRC58:

    • Graeme Dickey Jul 17, 2016, 10:16 pm

      Hi Henry – If you go to the Dickey Boats website – and find the LRC58 you can scroll through for some more photos and quite a good video too. There is also a link to a review by a local magazine. I understand hull number 3 is underway as well.

  • Jim R Oct 26, 2016, 1:35 pm

    Any updates on this? The second boat is launched.
    Jim R.

    • Graeme Dickey Oct 26, 2016, 11:46 pm

      Hi Jim. The first boat belonging to Dennis (the designer) is in Auckland. Hull number two is in Tahiti shortly bound for the Marquesas Islands then on to Panama and the Caribbean. Hull number 3 is still in build at Dickey Boats for a Scandinavian couple, completion not until 2017. Apparently still a lot of interest in this boat design. Not sure if there are any others sold

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