The Offshore Voyaging Reference Site

Thinking About Better Offshore Motorboats

Now that I have set the Adventure 40 free, I have some more mind share to think about other things. And one of those other things is making offshore motorboats better.

I started writing about this three years ago and to really understand the sailor’s motorboat concept you will need to read the original post, but here’s the short version.

A motorboat that is:

  • Able to cruise offshore at 8 knots or better with a top cruise speed of 10 knots.
  • Fuel efficient at that speed—two to four times better than trawlers currently available.
  • As safe offshore as a well-found sailboat.

A quick look at the trawlers available when I wrote the original post made it pretty clear that such a boat did not exist.

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Great to hear about this activity, something I am keen to know more about.

Late to this sailing lark, I had committed quite early on to the Adventure 40. However, being tied to the desk over the years has not allowed the opportunity to get the sea miles I need to feel even half competent with her. I’m looking to untie the lines in a couple of years so there is no time to get the experience I would feel adequate to sail seriously and safely so, reluctantly, had to look elsewhere to fulfill the dream.

The early LRC58 posts however got me thinking that the dream could become a reality. Having a bit of an engineering background the mechanics of the boat appeal to me. Not having to deal with sails makes me think I could venture more safely (for me) and enjoy the experience.

Many thanks in advance to all the sage advice that will follow from you and the broader Morgans Cloud community. A further thanks for all the wisdom Steve Dashew has available and shares freely. I’m learning a lot whilst desk bound.



Dick Stevenson

Hi John,
Exciting stuff.
Those of us around our age statistically only have a handful of years left where the rigors of wandering widely by sailboat are in the cards. I do mean statistically as many will go much longer, especially with all the aids possible these days, but we also know many who have already fallen by the wayside.
I suspect I will not need an “offshore passage maker” level power vessel, but I certainly would want one that could stand up to ugly waters and winds that coastal cruising sometimes throws one’s way.
I look forward to your continuing thoughts.
My best, Dick Stevenson, s/v Alchemy

Peter Mannerstråle

Off shore motorboat for ocean passage, why mono hull?
Would it not be better with a catamaran for fuel efficency, stability and space?
Price for berth may be the only negativ.

Catherine Hammond

We have just spent 4 months cruising through Indonesia and Malaysia in a rally which included 4 motorboats. We are the only powercat – a Chamberlin 12m. The others are a FPB64, a Selene 53 and Bond 80, all monos. We were by far the smallest of the 4, and in fact almost the smallest of the entire fleet, but our average cruising speed is 10 or 11 knots, with fast cruising at 13-14 knots. At our normal speed we are very fuel efficient at 1 to 1.1 litres per mile, total, and we also had the fastest cruising speed of the 4 boats. We very much appreciated our speed and being able to pick our weather opportunities. Admittedly this area of the world is fairly benign when talking about crossing oceans (except for the thunderstorms), but I feel a well designed powercat in a larger size, up to 50 foot would be suitable for passages in the usual “milk run”, and no, probably not the higher latitudes. The vast majority of powercats we see, both production and custom, are not well designed for the ocean, and are more of a house and entertainment platform, but this is certainly an area of boat design that has opportunities for the future.


Hi John,
Before you and Phyllis become totally committed to the concept of a ULDB aluminum motorboat I highly encourage you to hop on a plane for a week in Hawaii. (Looking out my window at the snow blowing sideways, the timing is definitely right!)

I can provide you with a short list of catamarans in the 52-60 foot range to ride on that will provide a definitive answer to the question of whether the platform is suitable for a sailor’s motorboat. Operationally most are motorsailors or motor boats with masts. They represent literally hundreds of thousands of hours of testing and development. I’m thinking of boats like Andy Evans’ Gold Coast 52 powered by a pair of 230hp Cummins that was delivered on it’s bottom from St. Croix and has been working in Hawaii for nearly 20 years.

If you like the concept then talk to me about a build technique that can enable a 50′ x 25′ power cat to be built for the same or less cost than an Artnautica type design. (And of course be unsinkable, faster, and equally fuel efficient)



Hi John,
Without going into details, the project (code name Cat Tracks) that I have in mind is uniquely suited to economical construction.

1- No accommodations in the hulls. Only machinery, storage and flotation foam. Freed from the necessity of designing around queen berths and the like, the hulls can be optimized to move through the water with maximum efficiency. And no labor intensive building an interior in the hulls and fitting it into small, curved spaces.
2- Because the hulls aren’t filled with accommodations they can be filled with foam– giving a whole new meaning to the concept of unsinkable. (see the history of Rainmaker — the Gunboat that just won’t go away in spite of not being designed with the intention of patrolling the Atlantic for years after being abandoned.)
3- Most of the boat will be built on a large flat surface vacuum table using resin infusion to produce a finished exterior surface with minimal fairing.
4- Twin engine get-home redundancy

There is nothing experimental about this kind of vessel as millions of drunken passengers can attest! Certainly not in comparison to a small engined, flat bottom 58′ ULDB long range motorboat where two or three examples have accumulated a few thousand miles.



Hi John,

As you say, there are a lot of ways to get the job done– and a boat designed for the ice is certainly different than one designed for the Bahamas.

re the Artnautica– I’m no motoryacht designer and have no direct experience with the boat so am in no position to pass final judgement on anything other than the fact that I like the styling. I did motor from San Diego to Panama at 8 knots on a 55′ sport fisherman with a flat bottom configuration, which left me with the opinion that that crossing oceans on that boat at that speed was not something I wanted to repeat! And I’m no fan of ULDB sailboats as cruisers. As a boat builder I understand that you can have ultralight, ultra strong, or ultra cheap— pick any one! The idea that boats are priced by the pound is only true if the materials design and technology required meet the structural demands is held constant.

Pointing out that the Artnautica design is a new and relatively unproven approach to long range cruising is simply factual. It bears little resemblance (apart from styling) to Steve Dashew’s proven LRC 65’s or to conventional trawlers. And pointing out that displacement catamaran hulls have millions of hours of development and service is equally factual.

Far from being negative about the Artnautica concept, I hope that it proves itself over time and that my reservations are unfounded. New alternatives are always welcome, especially when they are pleasing to the eye and fill a niche not currently well served.

Catherine Hammond

I did not mention in my previous comment that our 12 metre power cat has 2 x 110hp motors only. It has been designed for liveaboard, and not charter. Between the bows is filled in with light weight foam and there are no nets, and so potentially there could be a large number of people on the foredeck. Our particular design is affected by the weight and the distribution of the fuel load, and also because our total weight is only about 7 tons. The fuel tanks are fairly centrally located, and water tanks are at the cockpit area. Two “ballast” water tanks which are usually empty, are in the forepeaks, and can be used to balance the boat. Robin Chamberlin the designer has decades of designing multihulls, and his powercats are definitely not designed as sailing cats with the mast removed, they are a whole new shape underwater.

Catherine Hammond

Yes John, my husband built Catchcry I, every part and system except s/s welding and also one of the 10m versions, which looks very similar. Robin was continually consulted during the building process and worked closely with John. He became a fan of Robin Chamberlin after we built and sailed our 13.5 sailing cat Catchcry, a fantastic family live aboard cruising cat. Robin has had no boats built as a production” since the Stratus cats of his design about 20-30 years ago. We are from Australia where the market is much more tolerant of custom and home built boats. Robin learnt all about boats and sailing by numerous Tasman Sea crossings and thousands of miles of sailing and deliveries, sailed his (open bridedeck) cat Excess the furthest south to Antarctia and his son Kim is a qualified naval architect and is now involved with new designs.

Danny Blake

Hi John
Well I don’t think I’ve commented on your site since the last time you wrote about the LRC 58 although I have read just about everything you posted and comments since however I have been kept informed by Dennis of a boat being built in Europe to his design so I believe that will be 3 LRC 58 roaming around now, am really looking forward to the next instalment of offshore motorboats info.

Richard Dykiel

I like the design of the LRC59, except for the single engine. IMO a motor vessel cannot claim to be “long range” with just one engine. On the other hand, I guess the “self-righting” property may come in handy when the boat is dead in the water in a storm 🙂


Hi John,

This is a very interesting topic, which led me to further googling/reading. While doing this I came across the “diesel duck” series of boats, which on face value seem to meet some of the philosophical criteria that you have been discussing, and was wondering if you have any analysis on them. While I agree with you that twin engines provides the best redundancy and get-home options, the “sail assist” concept could be workable. I have often pondered the use of junk rigs for this type of application. Facinated by the Artnautica, looks like a great boat!


Thanks for the reply John, and I agree with your arguments regarding get home back-up! Regards, Tim

Carl Linley

Hi John,
As a boating adventurer, I have looked for the right tool for the job. I enjoy sailing but for a working stiff with limited time the range of a slow boat was a big problem. A fast powerboat proved to be the answer. We have been pushing the boundaries of our boats but have traveled from Maryland to Briar island NS. Every boat has its pluses and minuses. The jet boat was great in lobster floats but not great on durability. Now with Volvo Pod drives (3) lobster pot toggles are a thing of terror. I made the mistake of answering a questionnaire about Volvo drives thinking it came from Volvo. I said some engineer in Sweden should get a huge dope slap upside the head for putting the props out front. Turns out Bob Johnstone was the originator. I found that out during a meeting in NW harbor ME. Maybe that’s why MJM is building outboard boats now? The answer seems to be Canada for the time being. No pots. Looking ahead to more time for cruising, I find slowing down a possibility but not to 8 kts. A few years ago Soundings did an article about a very light, very long and narrow semi displacement boat. I am interested in learning if this type of boat could be used for coastal cruising beyond NS. I have followed the development of the FPB “unsailboat” and admire the design.
I do like to go fast though. Therein lies the rub.

Ray Chapman

I think the boats you are describing and possibly entertaining have been extensively discussed by the late George Beuhler. Many of his Diesel Ducks have proved his ideas and Idlewild a boat of his design completed the longest non-stop power voyage of a small yacht and is listed in Guiness Book. You could check out his book the Troller Yacht Book and his website (still up and plans are avaiable)
just throwing it out there.
Ray C.

Chris Leigh-Jones

I joined this form a few days back after exhausting about everything I could find on My wife and I are building a 78 foot long narrow design by Dennis of Artnautica. Machinery and internals are our own spec, twin diesel parallel hybrid (for fast battery charging mainly). The attraction was extreme range coming from an efficient hull and rugged build. My age likely precludes sailing for more years. An ex sea going engineer I should be ok with maintenance. Anyone considering such is welcome to visit the build in Antalya Turkey. Regards, Chris

Chris Leigh-Jones

Forgot the image, the “Christmas Elf” is a shipyard staffer:

xPM78 hull in frame.jpeg