Aluminum Row Boat

Discussion in 'Boat Design' started by fritzdfk, May 21, 2015.

  1. fritzdfk
    Joined: Jul 2004
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    fritzdfk Junior Member

    I am researching designs for a 10-12 foot row boat. The boat will be used as a courtesy dinghy for anyone to use to row out/back to their anchored boats. The current boat is a 12' standard riveted planing aluminum hull. I often watch people struggling to row it both from lack of experience and it being not designed for rowing. I think most plywood stitch and glue designs could be built in aluminum but what is the minimum size for welded aluminum? Do you know of any welded aluminum rowing designs that would be appropriate? I know that a stitch and glue plywood boat would work great but my higher ups can't be convinced that a wood boat would be serviceable and long lasting.
     
  2. gonzo
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    gonzo Senior Member

    In principle, any stitch and glue design can be made of welded metal. They are developable plates. There are all kinds of skiffs that would lend themselves to be built in aluminum. It probably won't be any heavier than a similar work boat in wood. However, a longer boat with less beam will be as stable, carry the same load, but row much easier. Is it possible to go to 15 feet?
     
  3. philSweet
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    philSweet Senior Member

    Depends on who you are, I guess. When I was 13, my next door neighbor in Detroit was a retired NASA guy named Mr Hill. He fabricated much of the instrumentation for the Voyager space craft. He could weld Reynolds Wrap back together. That was his warmup exercise when reworking a Smithsonian diorama or restoring a Faberge, which he did in his basement while I goofed around with old NASA junk and moon rocks. (Think Mr Wilson and Dennis the Menace.)
     
  4. Kevin Morin
    Joined: May 2013
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    Kevin Morin Junior Member

    small welded aluminum row boats

    Fritzdfk,
    those are some good questions so I'll make a stab at some (hopefully good) answers. First, I agree mostly with gonzo's remarks as regard stitch-n-glue requires developed panels layout as does sheet metal. Aluminum, generally, requires the same flat sheet panel outlines that will curve into flats & cones & cylindrical development from the flat sheet metal origins.

    what is not addressed (2nd) is the welding part of the concept. Unfortunately for welding smaller thinner metal boats- welding aluminum comes in three groups; < .100" (#1); 0.125" < 0.50" (#2) ; 1.0"<THICKER (#3).

    Welding ease (skill level) = #1 is 10 to 100 times more difficult than #2. # 3 is not important for the boats in question. Welding equipment is ten to a hundred times more critical for category #1 welding.

    Therefore, while I agree that any ply stitch and glue row boat design or kit would convert to welded aluminum that implies case #1 welding; (so) it would make a world of difference who tried to weld and with what exact equipment in that category.

    So what can we use to compare and help understand this circumstance? Let's refer to what is done by the thin scantling small aluminum builders; they don't weld. And the reason is that the cost of that skill level and equipment is not as cheap as press forming and riveting those thinner materials.

    That is why you see a riveted planing skiff being used now as the tender. IN order to handle thin aluminum cost effectively they choose one or two simple widely appealing designs (your row boat in question) and make millions of them to afford exotically expensive tooling needed to make the boat affordable.

    What can be done, well- if you already have good welding skills (I'd have to say that a minimum of 1,000 hours of welding begins 'good skills') and you have the needed TIG or MIG welding equipment and can spend time graduating decent or good skills to a higher level? (I'd have to say that was another 500 t0 1,000 hours in thinner work and exercises) THEN.... I'd say you can follow gonzo's concept of getting a successful stitch and glue boat and make it from sheet aluminum- welding it together.

    I'd like to make some further examples of some hurdles thin material presents. Willy-Boat on this Coast and many other builders build thin wall welded boats using 0.080" and other thin aluminum and they weld their boats.

    BUTTT... (you knew this was coming) this group of builders own a series of extrusions (own their own dies and control the sales of those shapes) that allow the sheet edges to be inserted into the heavy wall extrusion at the chine and the sheer so the open dories are welded in lap welds. Those extrusions are not generally for sale as they are proprietary to each welded drift dory maker (welder) so copying their design or build is very difficult when a newer/low hour welded is presented with two sheet edges that are 0.080" or even 0.100" thick.

    I'm reporting facts of life regarding aluminum welding both MIG and TIG, as I know them, of course always willing to learn how to work in thin stuff better but here's my efforts.

    [​IMG]

    This 1"=1'-0" model of 0.040", 0.060" and 0.080" is a seascape of welded aluminum I built as a memorial for a friend's son's passing. I welded for plural decades before I welded this and it was still pretty taxing to weld this little boat.

    For any welders reading, and for others I did the project using a cold wire feed TIG Gun that made it possible for me to do this work, I could not and don't personally know anyone who could have done this work with free hand/two hand TIG.

    I'm not saying all small boats of the class you're proposing to discuss are this thin, but the scantlings of that boat would be in this class unless the boat were to end up being quite heavy. This is category #1 welding required.

    [​IMG]

    Let's go back to gonzo's statement a bit? this gunning dory came from the lines of John Gardener's Dory Book (Chamberlain gunning dory) and I took the planked design and converted to 'stitch and glue'. The defining term is developed surfaces (or developable surfaces) for each panel.

    Its 17' LOA and about 4' wide will haul five people and row from three stations but... its all 0.100" or thinner and weighs about 175. lbs dry without rowing machines or oars. It has a 3" to 6" deep false bottom end flotation chambers and is all air tested and will remain afloat when filled to her gunwales with two people standing or sitting in her.

    [​IMG]

    She's fun in surf and salt water and although her high ends means she can't be kept bow to a stiff wind, she's a very nice and reliable row boat for the gravel beaches of South Central Alaska.

    Hinged oar locks to get added beam to the sweeps' geometry are all turned in here.

    Trouble is, being thin she is more work to build than an 18' planing skiff. Part of that work is the increased requirements for welding thinner aluminum.

    So... you've asked about thin small rowing boats, I'm very interested in working in this end of welded aluminum boats. I've shown a few examples of my work to help you weigh my 'credentials' pointing to the welding critical path going forward with your project.

    Gonzo's totally correct, as regards the idea you can pick ANY stitch and glue project you like, cut it from aluminum and weld it together. The last few steps in that sentence are far bigger steps than the words imply.

    The issue is aluminum welding scalability or weld proportionality to the parent metal's cross section. If anyone welds depositing cross sections much larger than the parent metals' (very common in aluminum) the resulting boat can be distorted, beyond homely and potentially dangerous depending on the lack of skills and knowledge of the welder.

    I'm not trying to say, or imply, or hint, or remotely infer..... that you can't build what I've shown here- yourself. I'm providing caution that the team you assemble for the build is critical. And high in that critical skills list is the welding experience and what equipment will be used to weld at category #1 small welded aluminum row boats.

    Hope to have helped as you learn more about small welded aluminum boats?

    Cheers,
    Kevin Morin
    Kenai, AK
     
  5. peterAustralia
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    peterAustralia Senior Member

  6. fritzdfk
    Joined: Jul 2004
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    fritzdfk Junior Member

    Thanks everyone for the very informative replies. it looks like it is possible if the builder has the required skill level. I have imagined a traditional flat bottom skiff designed for rowing. There are quite a few designs on the web. This is just one:

    [​IMG]

    This boat is 12' and there is a need to keep the length down as the area where it is kept is crowded. The location is Glacier Bay National Park in Southeast Alaska.
     
  7. fritzdfk
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    Location: Alaska

    fritzdfk Junior Member

  8. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I've always wanted to join two small aluminum runabouts at the stern to make a quick and easy faux longboat or mega-canoe.

    Sure, it wouldn't row or paddle 1/2 as well as a real purpose designed boat, but could be created without thousands of dollars of custom design and months in a real boat builder's shop. Might be OK for casual tourist use in calm waters, just so everyone can try rowing or paddling without worrying about boat handling.

    I figure a very short center coupler would be constructed to grab both boat at the gunnels and keel bulbs, so it would require butchering both boats, so they could still be returned to normal use.

    However, this would still be over 20' and probably not ideal for rowing out to other boats.


    For a quick and dirty, how about adding a streamlined stern extension to the existing alum row boat?

    Me personally, I think I'd take one gander at the costs of providing a suitable row boat, then I'd spend about 1/5 of that buying the best brand new deluxe low power outboard set up I could.:D I'm talking fully environmentally certified, cage on the prop to protect whales, probably 4stroke with dual electric/manual start, but if required a nice all electric would be fine since its all about the short trips. Run charging station down to dock. I'd guess one low powered boat would equal 3 row boats for your clients, and actually quite a bit safer.

    Any big restrictions against even 4stroke or elec boats in your venue? You mentioned Glacier National Park.
     

  9. Kevin Morin
    Joined: May 2013
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    Kevin Morin Junior Member

    SKiff build

    Fritzdfk,

    thanks for the offer but I'm not building at right now, I'm between shops and don't have my last business fully wrapped up so I have no space in which to work.

    For my money, the ply skiff you showed above was a more functional design than the pram for rowing or taxi to moorings?

    thanks again for the offer,

    Cheers,
    Kevin Morin
    Kenai, AK
     
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