One Tough Old Aluminum Boat

Line drawing of “Carina”, kindness of Ian McCurdy.

It is amazing how often people look surprised, and even mildly alarmed, when I tell them that we own an aluminum boat. The next tentative question(s) is almost always about electrolysis and the general longevity of the material.

For some reason there seems to be many stories of disaster, particularly on this side of the Atlantic, around aluminum as a boat building material. These stories normally go like this: “I have a friend, who knows a guy, who has a cousin, that bought an aluminum boat, and after a week in the marina the bottom fell out of her”.

The funny thing is that after 20 years of aluminum boat ownership and ten years of being a fairly high profile proponent of the material, I have yet to meet one of these mythical aluminum boat victims.

The fact is that as long as the boat is built out of the right aluminum alloys, and the right welding wire is used (all well documented), aluminum boats last longer and stay stronger and more stiff than boats built of any other material you can think of.

Which brings me to Carina, a McCurdy and Rhodes Custom 48—same designer as our own Morgan’s Cloud—that has just won the Newport Bermuda Race for the third time. Thing is, the first time Carina won, the leisure suit was in fashion…the year was 1970.

Carina won again in 2010, exactly forty years after her first win. And then again this year. And you know what Carina was doing between her second and third win? She sailed around the world clocking up 42,000 miles. And while she was at it, she did a few races…like The Trans-Atlantic, The Sydney Hobart and The Fastnet—not exactly known as walks in the park.

One tough old bird that aluminum boat…fast too.

I spoke with Rives Potts, who is not only Carina’s owner and skipper, but also runs Pilots Point Marine. Rives has been involved in building and repairing many aluminum boats over the years. He had this to say:

    • If an aluminum boat is built of the right alloys and the right welding wire is used, she will last essentially forever.
    • The great thing about aluminum is that what you see is what you get—if you have a problem, you can see it.
    • He has not had to make any structural repairs to Carina. And she shows no significant corrosion.
    • She is still incredibly stiff and strong after 43 years of hard voyaging and racing.
    • And because Carina is stiff, she is still fast and it is much easier to keep the deck fittings and hatches watertight than it would be on a boat that flexes more.
    • When he has seen corrosion damage on aluminum boats—usually the result of a wiring problem or an inaccessible area where debris has lain for years—it is confined to a small area and is easy to repair as good as new by cutting out the plate with a skill saw and welding in new plate. Just make sure you use the right alloy plate and the right welding rod.
    • Repairs and modifications to an aluminum boat are easier [that means cheaper too] than they are on boats built of most other materials.
    • The only real drawback of aluminum is keeping paint on it. But if the paint job is done right even that issue can be overcome.

So if you are looking for a boat to take you offshore safely and comfortably, don’t look past that old aluminum boat. She might have a few years and miles left in her…or a few decades and a few circumnavigations.

And if you are crazy enough to embark on a major refit, at least if  you are restoring a well built aluminum boat, you will know that you are investing in a good hull, unlike poor stupid Bob.


We are cruising the south coast of Newfoundland, where internet availability is scarce, so it may be some time before we can respond to comments.

Further Reading

{ 54 comments… add one }

  • Michael Shea July 3, 2012, 9:49 am

    Very true. As a fellow 40-year old McC&R (Luke-built) aluminum sailboat owner, I couldn’t be happier. There is simply nothing as secure, quiet or comforting as racing through the ocean in a metal. No flex, no squeaks, no leaks, no oil canning…just pure power and smooth sea motion. Mine ws refit with a ‘wooden boat interior’ for the best of both worlds. Of course, most of this credit is due to her designer but there is no question that aluminum is a terrific material from which to craft a boat. Commom sense prevents all the rumors.

  • C. Dan July 3, 2012, 10:41 am

    And yet… not for the Adventure 40?

    • John July 7, 2012, 2:39 pm

      Hi C. Dan,

      If we could do aluminum at the price point, then maybe. However remember that the Adventure 40 is not going to be the ultimate offshore boat. Rather she will be the ultimate value in an offshore boat. Just painting the decks and bottom properly of an aluminum Adventure 40 would, I estimate, add US$10,000-15,000 to the price in comparison to a fiberglass version. And realistically, how many people in the mass market will buy an unpainted aluminum boat, particularly in North America? So add in painting the hull, and we are up over $20,000, just for painting.

      • Jean-François July 9, 2012, 5:55 am

        Dear John,

        I confirm your figure for deck and bottom for a Adventure 40 with a simple deck shape and if the welding job is done correctly so you don’t have layers and layers of filler to applicate.

        But for a hull you would need to add much more than the additional 5000 you mention…. Mostly to the get the hull ready to paint.

        I understand what you say about the willingness to have an unpainted hull but at the same time painting the hull would be – in my eyes – against the philospohy of the Adventure 40 and the idea of low maintenance

        And the first scratch is a very expensive one…


        • Bruno July 9, 2012, 7:34 am

          i have actually a question on that one, and more specificaly on painted decks, as i have to remove the many layers of different ugly paints and the antislip on good old “Moscatel”,
          i will sandblast it first, and i’m actually considering leaving those decks blank, or at least where it does not need antislip,
          what would be yr feelings abt that ?
          next question is of course which antislip to apply after that …
          The hull would remain as it is, as it was originaly faired by epoxi resins and painted, and repainted epoxi,
          the result should something like that :

          • John July 9, 2012, 5:48 pm

            Hi Bruno,

            If it were me, I would use Treadmaster. See this post for some tips.

            Also, type “Treadmaster” into the site search box next to the menu for many more articles on this material and our experience with it.

          • Jean-François July 11, 2012, 12:24 pm

            Hey Bruno,

            It seems like you have a Romanée…

            One thing : You don’t know what you will discover under your paint. There might quite some filler… If you sandblast you have to remove everything.

            On our first boat, we sandblast the deck to remove everyhting. It took us much more time and sand than we tought. At some place we had several cm of filler…
            As the paint was ugly but ok when we had removed the 20 year old treadmaster, we would have been better of with just a new layer of paint and new Treadmaster or a (Sicomin) anti slip paint…

            After sanding we did ourselves a complete cycle of paint on some part of the saloon (and the hull) because of ethetics. 12 years later the paint is still perfect.

        • John July 9, 2012, 5:46 pm

          Hi Jean-François,

          Great to have your confirmation and correction of my cost guess, thank you.

          If it were my boat I would not even paint the deck, just Treadmaster. But can the Adventure 40 be like that and sell enough hulls? I fear not, although I don’t know for sure.

          I note that you made the decision to paint the decks and cabin of your Boreal boats. Was that driven by marketing and sales or another reason?

          I think that this may be the crux of the hull material decision: if we have to paint even just the deck, then that is probably a killer for aluminum, if not…

          • Jean-François July 11, 2012, 11:58 am

            Hi John,

            There are different answers to your question. Some elements which contributed to our choice :
            – esthetics : general look of the boat. We did not want an all “grey” boat.
            (But note that at the same time, we did not want any paint on the hull. This has determined the way we build the hull)
            – esthetics : we wanted the look of the deck and the saloon to be tight and tidy. Said in another : we wanted way to hide the imperfections of the boilerwork. Therefor we wanted filler, therefor we have paint…
            – antislip : we do not discuss the effectiveness and the qualities of Treadmastesr, but esthetics is another question. Moreover the day you have to remove it, it is a very very hard hard job (Bruno will confirm). You can also say that walking barefoot on it is not very pleasant. We use as anti-slip paint made by Sicomin Deck Line (bi component). The constitution of the paint makes it is “elastic”. It is either sprayed or applied with a roller. The way you apply it will determine its final aspect.
            So under the antislip we apply the whole cycle of paint all over deck and deckhouse.

            Note that the traditional paints are mechanilly bonded on the aluminium.
            Now there are paints coming up which are bonding chemically tothe aluminium. This does make the process “lighter” because the surface oxide is not a problem.
            There is a Swedish boatyard which is doing some tests with it. It is (at least here in Europe) pretty new and there is no feedback yet.

            I hope this helps…

          • bruno July 11, 2012, 5:47 pm

            many thks for yr feedback on antislip and deckpaint, and yes, the good old Romanée needs some efficient cosmetics, foreseen for next winter, you are both right, and a choice will have to be made, after blasting,
            i’m also really convinced by antislip paints, as i use them since 25 years on my (job) oceangoing steelships, we just mix antislip slints during our epoxi-polyurethane cyclus, and this work great and easy, nice surfaces, good holding,
            But as you say, the chemical bonding is usually a bit of a problem on aluminum, and i hate to re-do things too fast …
            I have now no choice but to sandblast, i’m quite confident on the surface condition, as she is a 1979 (they started to build them in 1973), and hopefully used less filler 6 years later (i might check with builder G.Fillon), some even sandblasted the hull after years and left it blank,
            After that, i’ll have to make a (fast) choice, as for so many (good) things in life …
            thanks again !

  • Abel van Staveren July 3, 2012, 11:32 am

    Great post and reassuring comments from you experts for greenhorn Alu owners like us. We acquired a 23 year old alu Koopmans 48 last year and so far have nothing to complain about. Amazed at the speed considering her weight. We carry 8 tons of lead due to the lifting keel having no ballast so she weighs twice as much as the tupperware equivalent. Hull lines look fairly similar to the Carina

    • Petter July 3, 2012, 7:23 pm

      hello Abel,
      it appears that we sail very similar vessels. might be both fun and useful to connect. I see that you plan to enjoy Norway – and my Koopmans is one of two currently based there. Feel free to reach me at
      rgds, Petter

  • Colin Speedie July 3, 2012, 2:48 pm

    Not only a great material, but a great looking boat too – lovely sheerline.

    A boat to gladden the heart of any owner – no wonder he’s hung on to her!

    Best wishes


  • Bill July 4, 2012, 7:32 am

    What is the correct aluminum alloy and rod?

    • Matt Marsh July 5, 2012, 11:04 pm

      Hull plating is usually done in strain hardened alloys 5083 or 5086 (also common are 5456 and the slightly weaker 5054).

      Framing could be 5000-series but is more commonly of 6061-T6.

      I’ve never seen anyone stick-weld aluminum; it is usually welded by MIG (with a 5000-series electrode) or TIG techniques, with an argon or helium/argon shielding gas.

      Aluminum is tricky to weld correctly and is very prone to fatigue around bad welds. When you combine a knowledgeable designer and a skilled welder, you can end up with aluminum hulls that will last almost indefinitely. If you give incorrect detail drawings to someone who isn’t quite so good with a MIG torch, you’ll get stress risers, poor returns and poor penetration, and you’ll find yourself wondering why the boat’s full of fatigue cracks in her second season. If you want to use aluminum, it’s really important that everyone involved takes the time to learn how to use it correctly- this means a lot of reading, and a lot of practice on bits of scrap.

      • John July 7, 2012, 2:17 pm

        Hi Matt,

        All good information, thank you. Also, thanks for the correction on stick welding. When I said “rod” I was speaking generically, but, of course, it is wire that is used.

      • Bill Stine July 10, 2012, 8:19 am

        Great info, this is the first I have seen this list of aluminum types, Is there a way to find which aluminum types were/are used by the companies that build aluminum sailboats?

      • Jean-François July 11, 2012, 12:13 pm

        Hi Matt,

        Absolutely perfect information. I’m happy I had not to answer this one as you express things in a much clearer way than I can do.

        Note that theoretically all alumiunium with the same denomination (5083 or 5086) should be exactly the same.

        According to our insurance they have on regular base claims from non conform aluminium coming from some countries.
        In our contract we commint our Aluminium is coming from Norway, Holland or France.
        Each plate is marked and you can track the origin…

        Bill : the constructor should mention in his technical description which aluminium he uses for what. During the construction you should be able to see it on the plates…

      • Andrew Troup April 3, 2013, 4:45 pm

        The preferred electrode/filler wire grade for MIG and TIG is 5356: this *can* be used to weld 6061 as well as the 50xx alloys for the plating.
        (Incidentally, it *should* be used for 6061 for any weldment which will be anodised.)
        Opinions differ on whether there’s any electrochemical issues when combining 6061 framing or welded thru-hulls etc vs 50xx plating
        If there are problems, it seems likely they’re either very subtle, or only arise under highly unusual circumstances.
        Some builders hedge their bets by preferring to avoid this combination below (heeled) waterlines for thru-hulls, or in the bilge-water zone for interior framing.

  • Viv and Mireille July 4, 2012, 8:14 am

    Thanks for the reassurance on aluminum! (UK spelling now!) I really think it is the best material to date for ocean sailing.

  • Bruno July 4, 2012, 11:26 am

    definitely what i think, but good to share the same feelings on our old sweet lines strong and light hulls …
    i would say the same, especially for Europe, whay not the A40 …,
    had a look at those : ?

  • Jean-François July 4, 2012, 11:46 am

    Dear John,

    All very true.

    One additional reality at least in Europe – it might not be true in the US – is that the second value of an aluminum boat stays longer high.

    Most probably, we would all be amazed to hear what Abel has paid for his 23 old year boat… And I believe that, correctly maintained, she will keep her nominal value through the years…

    Best regards,


    • Abel van Staveren July 5, 2012, 5:59 am


      You’re spot on, after insurance survey it is insured for EUR 2ooK and the surveyor said that if properly maintained, it will not depreciate. Lets see ;-))

  • Viv and Mireille July 9, 2012, 7:22 am

    I personally would be happy with a bare hull/deck in aluminum. Functionality is to me the essence of the Adventure 40 but As you said yourself John, maybe North America is not ready for the sight of a naked hull! In Europe going topless is the norm so a hull without topside paint is not considered garish at all.

    I like the purposefulness that an unpainted aluminum hull presents, like driving a Land Rover Defender instead of a Range Rover, one is to do and the other is to show. The point of the Adventure 40 is to get people into sailing that is more than marina hopping but is a build-up to ocean sailing and world travel. I can see that a composite hull at an attractive price would maybe attract more people to the way of life, but would it not just become another plastic boat? There are many really good boats out there and a lot of floating condos as well, all in plastic. By being different, cutting edge and innovative, then the Adventure 40 could be a winner.

    I understand that lots of us writing on this great site have a fair amount of sailing under our belts and maybe we are not the market for the A40. So, personally I would go for aluminum, but is that good for the A40 concept – that I don’t know.

    • John July 9, 2012, 5:39 pm

      Hi Viv,

      What a great comment, thank you. Sums up the conflict that I feel too on this point exactly.

      • Ann July 11, 2012, 6:32 am

        I agree with Viv about the ‘purposefulness of an unpainted aluminum hull’. I see the A40 as being a no-nonsense, functional and purpose-built boat. When I signed-up to express an interest in purchasing one, I misunderstood and had assumed that it would be a metal boat. If it’s just going to be another plastic boat, albeit a well-designed one, I’m not so sure there would be enough difference to set it apart from all the other ones out there. I know it’s impossible to design by committee, but, maybe a poll of your potential buyers would provide valuable feedback on the aluminum painted/unpainted question?


        • John July 11, 2012, 7:49 am

          Hi Ann,

          I think that at some point a poll of sign-ups on this and other design decisions might be a very good idea.

          However, I can’t agree that just because the hull material ends up being composite, rather than aluminum, that this would make the Adventure 40 “just another plastic boat”.

          Whatever material the boat is built from, the Adventure-40 will be stronger, faster, more comfortable at sea, more reliable and significantly less expensive to buy and own than anything else on the market. That is anything but a “me too boat”.

          • Nelson Raines July 16, 2012, 8:18 pm

            John, Viv and Mireille I agree completely.
            Your analysis is spot on. Some cleverly expressed idea’s and philosophy’s. (personally I loved my old series three landie)

            I think the 1st A40 should be grp given the target market. That target market needs only to dockside walk to hear all those “horror” stories about electrolysis!
            Perhaps a model II (grp OR aluminium high lat. version) could be slated for future production depending on buyer interest.

            I would prefer the ali boat myself but your target market won’t as they r either new to voyaging or not into the specialised high latitude voyaging yet..
            Give them time to voyage. Some will be happy on the trade wind/low latitude route and they have the perfect tool for it.
            But some will retain the philosophy that sent them to sea in the first place.. the desire to seek new experiences.
            These will be your repeat customers and some will want a new tool for the job of high latitude sailing.

            As I understand it the initial brief was for a seagoing VW beetle ie. a low cost entry level tool that does it’s intended task very well. A great design through a well engineered (strong AND eficient to build) great sailing easy to maintain product.

          • John July 17, 2012, 7:51 am

            Hi Nelson,

            Thanks for the great and very clear comment. Much as I am a big fan of aluminum, I think you are probably correct in your reasoning.

  • Bruno July 9, 2012, 7:42 am

    exactly …
    kind of a light(er) Peter Smith’s “Kiwi Roa” ???

    • Victor Raymond July 20, 2012, 2:07 am

      Peter Smith did the fitting out interior and exterior of my boat but the hull is from Meta in Tarare, FRANCE. Built in Stongall. Big job to all the paint off that Peter put on. He did a good job, too good in my opinion. Now it is time to leave raw.

  • Michael Shea July 9, 2012, 7:32 pm

    My 40-year old aluminum deck was painted and covered with Treadmaster before I bought her. The epoxy holding the Treadmaster to the deck is a tight a bond. Fantastic grip. Very acceptable aesthetic. The decks will need to be redone within the next few years and I do debate how best to address this. Bare aluminum would be fine if the boat were new but I wonder how it will look after all these years of minor corrosion, faring, dents and dings. No question, if you remove paint from the equation, aluminum has few complaints.

    • Victor Raymond July 20, 2012, 2:11 am

      I have rolls and rolls of Treadmaster which I will NOT be putting on my aluminum deck once all the paint is removed. I will sell at a very fair price. I am presently in the Seattle area. I have both textures in light beige color. Interested?

      • RDE (Richard Elder) July 20, 2012, 6:10 pm

        Hi Victor,
        I may have a repair job coming up that will require Treadmaster. Keep me in mind and contact me through John if you haven’t sold it in a week or so.

        Congratulations on your long delivery up from Panama, and welcome back to the land of cool rain!

        • Victor Raymond July 20, 2012, 8:47 pm

          Hello Richard
          Thank you. You have been on my call list for a while and I will do so when back in Jackson (assuming I get there.) As you may have gathered I have started the refit here in Port Townsend with Carol Hasse and Brion Toss as my primary support team for sails and rigging respectively. I hope to also have a removable hard dodger welded up. I have a nice naval architect from Portland helping me with the design.
          If you decide you want the Treadmaster I could bring it back to Wyoming or ship to wherever it is needed. I have both textures and would have inventory how much of each but certainly enough for a 45-50 foot boat.
          I have decided to paint on what the local alloy fishing trawlers use here. It is easy to touch up abused areas rather than matching up sections of Treadmaster. It won’t ever look as nice but my boat will never look nice so why bother? I am more concerned with the esthetics of function rather than the esthetics of lookin pretty.
          Hope to catch up with soon. I have Steve Strand coming down from Canada to look at Rajah Laut this Sunday. He sold Ocean Watch their steel boat a few years back. He is also doing a big aluminum project in the Philippines.
          Anyhow more later..

          • bruno July 21, 2012, 4:09 am

            Hi Victor,
            what do the local alu trawlers use then ?
            usual epoxi paints with antislip slints ?

  • Nelson Raines July 17, 2012, 12:29 pm

    Cheers John,
    Although the a40’s not my next yacht I’ll keep following the development as I feel you have something here.

    Anyone know if a cruising yacht has ever gone through this sort of development.. I would think not which indicates you have something unique.

    On a different note and speaking as a parsimonious cruising sailor even I would be happy to send AAC some of our well hoarded funds for the value of ideas, experience and content contained herein.

    Keep it up as AAC is appreciated and has real value..

  • willy November 27, 2013, 6:18 pm

    Listen guys , I am going to order my new Garcia 55 exploration under Jimmy Cornell´s supervision and collaboration. I guess will be one of the best blue cruisiers actually in the world.

    • John November 28, 2013, 10:47 am

      Hi Willy,

      Note that the boat Jimmy Cornell is having built is 45 not 55. I also have some severe reservations about the boat, particularly the twin rudders which are, in my opinion, not a good idea, particularly around ice.

      Before you pull the trigger on that boat, I would suggest you at least look at the Boreal and talk to the people at Boreal for a different view.

      Disclosure: Boreal is a corporate member and supporter of this site.

  • bruno November 28, 2013, 2:35 pm

    any idea of the price tag for the exploration 45 ?
    i could not find much tech details so far,

    just read that Boreal has a two years full order book, seems they found their market ! great ! and this without counting all the ones dreaming of it …

  • Laurent November 29, 2013, 9:21 am

    I found a selling price info on a copy of a Yachting World report at adress: .

    According to this report, October 2013 price tag should be 425k€ + VAT.

    Looking at all Allure/Garcia/Outremer/Alumarine current production, Garcia Exploration 45 seems to have some similarities with Allure-Yachting Allure 45 (same: length, architects, workshops etc…).
    I wonder if a ruggerised Allure 45 might not be not very different from a Garcia Exploration 45 with a lower price tag….

  • Steve Stucko January 9, 2014, 9:51 am

    Great piece, thank you for sharing it.
    We just purchased a an aluminum Rumba 41 which has two areas of the hull that are corroded because of the failure of the resin encapsulating the steel ballast. We are receiving conflicting advice on the preferred repair method. Some argue for drilling our each small crater (there are many) welding in a small backer and filling the hole with weld from the outside. The other camp suggests simply cutting out the two sections and welding in new plate (each about 12″x 42″). Can you lend any insight or thoughts about these options?
    Thank you,

    • John January 9, 2014, 3:13 pm

      Hi Steve,

      Hum, this is a tricky repair. The problem is welding aluminium in the presence of the ballast without contaminating the welds and also heat conduction by the ballast making for cold welds. If it were me, I think I would simply weld a patch over the existing area without cutting anything out, and then fair it in with epoxy putty.

      Make sure you get a top grade welder to do this, because getting the heat right is going to be tricky.

      By the way, anyone who tells you to fill a hole with weld bead is not a competent person to work on an aluminum boat and should be ignored. There is no way to get a proper and reliable repair with this wrong, but all too popular, approach.

      One other thing. I’m concerned about steel ballast in an aluminium boat. I have never seen that before. I would want to investigate what exactly the situation is and be very sure that no water can get into the weld cavity.

      • Jean-François EEMAN January 9, 2014, 6:22 pm

        Hi Steve,

        I do share John’s vision.
        I just want to overstress the importance of getting rid of the cause of the problem.
        How is the ballast insulated from the hull ? You know ?
        Don’t take the risk to melt that insulation…

        Why would you cut out the plate ?

        Note that it is always very very difficult to judge a situation and give advice without having seen the reality.

    • bruno January 9, 2014, 9:43 pm

      Hi Steve, nice boat !
      isn’t it a swinging keel or a fixed keel ?
      anyhow, this is a well known problem on those early aluminium designs, with leaking encapsulation,
      Harlé got the same on some of our Romanée (fix keel) where the resin seal in the bilges was cracking after a few years by her lack of elasticity. and bilge water leaking through to the lead, making a great battery of the keel, with corrosion as a consequence,
      Most owners of the affected boat keels have indeed cut the bad plates and made a new insert taking care of inserting another aluminium flat bar behing the new weld in order to avoid a smelting lead contamination of the new weld, it worked well !
      If your ballast is steel, you might not have that problem of melting ballast, unless the ballast itself has been encapsulated in some resin which might melt as well !.

      but indeed as Jean-François underlined, the main thing is to solve the original problem first, which usually is a leak in bilges well to the keel, or water the keel in the keel in some way,

      so after cutting this bad area which was usually juster under the bilge, they inserted and welded an horizontal plate in the keel to seal the bilge well hermeticaly instead of the resin.

      The other solution of drilling and filling by welding the craters from outside is indeed bad on a lead ballast because the lead will melt when welding and in the welding seem …

      What others also did, is drill the craters and just fill them with modern epoxi resins !! it works also … but you then first have to find a way to drain the liquid which is still inside and dry, or you’ll get more holes later on !

      To solve the bilge problem on healthy boats (like mine) where the water did not reach the ballast yet, most of us poured modern “flexible” epoxi resins on the bottom of the bilge well, like International Watertite, e.g.

      Good luck and fair winds !
      PS : i did not hear of any of those surty boat loosing their keel for that reason !

    • John January 10, 2014, 12:36 pm

      Hi Steve,

      You have got some great advice here from people who really know: Jean-François is a boat builder and Bruno clearly knows your boat.

      The key take away, as far as I can see, it to be careful of weld contamination and make sure you get the the bottom of what caused the problem in the first place and make sure that the keel cavity is dry and watertight after the repair.

  • M Eliason January 10, 2014, 2:00 am

    Thanks for your site I too have been on the lol out for the mythical elecrosis boat:…… I have a 35 year old koopmans it has some corrosion on stanching bases not same type al and a bit where toenail is bolted on basically I am certain that I could let it go 35 more years and it would not be a problem I am baffled by the volume of cynics who have zero experience in short al is in my limited exp the toughest inch to inch most maintenance free easy to repeat material I have seen it’s really easy to put on a sloppy mig weld with argon shield then tug to clean up id desired also grinds out way easier than steel

  • rene September 9, 2014, 10:01 pm

    Thank you for very interesting info on aluminum boats.
    Recently purchased a dutch built 60ft aluminum motorboat in seattle.
    The teak deck is fastened with self tappers thru the alu deck and after 30 years, it may be time to look for something else. Have been told to cover the teak with the kiwi product, but don’t like the looks of it. another; just put the tread-master over the teak deck?? I prefer a low maintenance ( alu) deck and if need be with a tread-master finish.
    Look forward to any suggestions.

    • John September 10, 2014, 9:02 am

      Hi Rene,

      I’m afraid there is only one right way to do this: remove the old teak deck, plug the holes and then coat deck with non-skid paint or Treadmaster. This issue is one of the biggest, maybe the biggest, drawbacks of old aluminium boats. If you cover the teak you are sealing in water and since the screws are probably stainless steel, creating a big corrosion problem.

      Within this job, the biggest challenge is how to plug the holes. Welding is an option, but is usually not practical because the boat is probably insulated with foam, which will burn. Probably the best option is to drill the holes out, tap them, and thread in an aluminium flat head countersunk machine screw to seal it. Some, maybe many, of the screw holes will probably be severally corroded through dissimilar metal corrosion, so you may need quite large machine screws.

  • rene September 10, 2014, 3:13 pm

    Thank you John for your advice.
    By sending an email to your website, I hoped to learn of any new short-cut on the market. You confirmed there is none, at least none that keeps the boat seaworthy longterm. First thought of covering the old deck and holes with a new alu plate, but the insulation prevents welding. I see maintenance as part of the hobby, so no problem.
    Thanks again.

  • Ren September 25, 2014, 2:06 pm

    What would cause the plating of an aluminum boat to get thinner ? Is it electrolysis ? What can be done to prevent it?
    I know a boat for sale that had plates replaced due to thinning. Would like to know why it happened and how to prevent it from happening again.
    Thinning happened in bow area and under the engine area.

    • John September 25, 2014, 4:17 pm

      Hi Ren,

      There is no intrinsic reason that aluminium plate should thin over time. Or to put it another way, there is something wrong with that boat that caused the problem. Look for: no isolation transformer; non-floating DC system, or one that is supposed to be, but isn’t; wrong paint (copper content) copper or iron salts dripping off fittings, or the engine, that were left for very long periods; dissimilar metals that are supposed to be isolated from the hull, but aren’t; not enough zincs, or poor quality ones.


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