Deep V Fiberglass hull: Replace plywood floor with aluminum

Discussion in 'Fiberglass and Composite Boat Building' started by tkcamsoil, Aug 5, 2013.

  1. tkcamsoil
    Joined: Aug 2013
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    Location: Newberg, OR

    tkcamsoil New Member

    I have a 1968 Larson Volero 197, that I found in a farm field...and it used to belong to my grandfather. So I bought it, and I want to not only resurrect it, but to make it better that it was when it was new.

    Has anyone ever done this? I want to tear out the badly decayed plywood floor, stringers, etc. and replace with aluminum stringers, design in-floor storage compartments and live-wells, install a 1/4" aluminum diamond plate floor and then coat it with a spray-in bed liner product. So my question is... Has it been done before? What are the suggestions for fastening the new stringers to the fiberglass hull?

    Thanks,
    Toney
     

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  2. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    Sounds monsterous.

    WHY ?

    Plywood is lightweight, strong, cheap, easy to work with, easy to bond to Fiberglass and when correctly sealed with epoxy , with all fittings set in bedding coumpound, its very long lasting.
     
  3. tkcamsoil
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    tkcamsoil New Member

    I tend to over-build just about everything I've ever built...only want to do it once. This boat has a dry weight of 2600lbs as it is. I figured I could actually lighten it up a bit by implementing an aluminum floor system. I've not done fiberglass work before, but I have a lot of fabrication and carpentry experience in my diverse background. I'm not totally opposed to plywood and fiberglass, but either way I do want in-floor storage, live wells, as well as easy access to bilges and pumps to keep them clean and functioning well.
     
  4. tkcamsoil
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    tkcamsoil New Member

    This boat also uses pedestal mounted captains chairs at the helm and co-pilot positions. I want to make sure it's nearly impossible for them to rip out of the floor if conditions get a little rough when I have it out in the bay or going across the bar in and out of the bay. My goal is durable, well-designed, and looks good when I'm done.
     
  5. missinginaction
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    missinginaction Senior Member

    While I give you credit for wanting to do a good job, I think that you are contemplating a complex job that will be far more expensive and time consuming than is necessary. There are techniques (called composite construction) that utilize epoxy, fiberglass, modern adhesive/sealants, appropriate hardwoods with marine plywood that will produce extremely strong structures.

    I can understand your horror looking at that old rotted out stringer/floor assembly. The building techniques and materials available when your boat was originally built are vastly inferior to the products/techniques available today. Do your homework and don't be afraid of wood. Wood can be a disaster, as you know. Done right though wood can and is a lightweight and extremely strong material, pound for pound much stronger than metals. The key is "done right".
     
  6. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    I'm a wood man and ditto the above. Save yourself some heart ache and a lot of money
    and add some flotation for those Oregon waters and bars.
     
  7. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    So what is this mysterious wood that is "much stronger than metals " ? The boats that I see smashed to bits after hitting rocks etc or going aground in storm conditions aren't the steel ones !
     
  8. tkcamsoil
    Joined: Aug 2013
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    tkcamsoil New Member

    Perhaps one way to go would be a combination of the two. I could use marine plywood encapsulated in marine epoxy for all of the under floor structure and compartments and then install 3/16 or 1/4" 2 x 2 aluminum angle flush to the tops of all the stringers to be able to have a suitable material drill and tap to secure the aluminum diamond plate floor. This in my mind would greatly simplify the dilemma of trying to graft aluminum stringers and under floor structure to the hull of the boat. Based on other threads I have read on the subject of floor replacement, the most important thing to remember is to over-size any holes for fasteners to coat the inside of the holes with the epoxy to ensure that the plywood is completely impervious to moisture. I could then reinforce the under side of the aluminum deck with aluminum angle or aluminum flat bar in the spots where my captains chairs are mounted. It's a lot of work no matter what method I choose, and as long I can ensure I get another 30 to 40 years out of the boat, which will take me into my retirement years, then I know I did a good job.
    It may not be as bad as I think under that floor right now, I have yet to tear into it. All I know is that the whole floor is quite soft almost to the point of not being able to stand on it.
    I appreciate all the valuable input and advice from everyone. I plan to start the tear-out of the floor in the next couple months.
     
  9. missinginaction
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    missinginaction Senior Member

    That's a fair question Mr. E, but you need to read my post again. I said pound for pound wood can be and often is much stronger than metals . That is a true statement, pound for pound.
     
  10. gonzo
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    gonzo Senior Member

    If you were to replaced the floors and stringers the same as the originals, they would last many years. They rotted because many of the edges and holes were not sealed. If you seal the plywood, even with paint, the boat will last longer than you. Expensive repairs, which also add weight, are not better but worse.
     
  11. RufNutt
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    RufNutt Junior Member

    Also I noticed , the design in my boat was not good .I think what most manufactures did was build a hull with drainage holes below deck leading back to the bilge. Then they kept using this design after adding flotation foam to these areas. They left the drainage holes there half plugged with foam so when water got into these areas over the years the water never really gets to fully drain out and the inevitable rot begins. If you live in a freeze thaw climate it makes for other problems if your hull holds any moisture. Then comes the redesign to keep these areas filled with foam dry. Some say add drainage some say keep it dry . I just don't think water and foam work good together.
     
  12. missinginaction
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    missinginaction Senior Member

    How many boats have you seen, especially smaller boats, that are filled with flotation but have a cheap, tiny bilge pump installed in a location that makes maintenance next to impossible? Most folks don't like the idea of paying hundreds of dollars to install good quality decent capacity bilge pumps. I've installed three pumps in our small 27' cruiser. Two electric and an attachment to the seacock that enables the boats engine to act as a bilge pump in an emergency by pumping flooding bilge water through the engine cooling system. I hope I never need it but it's there if I do. There is no foam flotation anywhere. The spaces below the cabin sole are open so that fans can move air around to keep internal areas dry and as free as possible from any accumulating water. Condensation is an issue that doesn't get nearly the attention it deserves.
     
  13. SamSam
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    SamSam Senior Member

    The connection all around between the edge of the floor and the sides of the boat, and the transom etc are very important. Without it the boat will be very flexible, the hull will twist and shift independently of the floor. It softens the ride but wrecks the boat. I don't see how you can make a connection between an aluminum floor and fiberglass hull that would work.
     
  14. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I see no advantage using a soft, quite flexible material as the sole (like aluminum) on a boat like this. To do so successfully, you'll need a considerable amount of support under the plate, to pick up longitudinal and athwart loads. The supports would need a positive fastening system (hard fastening or welding). Ring frames or extruded shapes could be used for the supports, but you'll rival the weight of plywood, with a lot more filldlyness.
     

  15. tunnels

    tunnels Previous Member

    One of the biggest problems using dissimilar materials is there attach-ability to one another nothing sticks to aluminium particularly well in the way of laminating epoxy resins it will simply part company after while and all will come loose !.Even of you screw , bolt , rivet or what every the chances of it coming apart are pretty high so I would wipe it off the list
    Attaching wooden stringers to the glass hull is not a problem !
    attaching a wooden floor onto the stringers is not a problem !
    Making lift outs to be able to access under the floors not a problem !
    Live bait wells could be plastic bins as drop in's again not a problem !

    the floor made from 12 mm ply fitted and shaped then resin coated all sides especially the edges and any end grain !!, a light glass on the underside and when fixed in place glassed over and flo coat would be your best options .

    Like has already been said the floor makes the hull ridged and so it i doesn't twist !!, raking can cause all kinds of problems with cracking in the corners of the deck etc etc and things coming loose ,so a solid ply floor well glassed into the hull is really important not only for standing on but structural as well :p!!
     
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