Aluminum transom beef up

Discussion in 'Metal Boat Building' started by Ry Scott, Apr 29, 2020.

  1. Ry Scott
    Joined: Apr 2020
    Posts: 11
    Likes: 3, Points: 3
    Location: Kansas

    Ry Scott Junior Member

    If I was to go with another foam like sheet foam what would be the best to use? Does it work as good? Should I start saving up 2 liter bottles? Lol
     
  2. Ry Scott
    Joined: Apr 2020
    Posts: 11
    Likes: 3, Points: 3
    Location: Kansas

    Ry Scott Junior Member

    Ping pong balls? I kid
     
  3. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,868
    Likes: 878, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Polystyrene blocks work, provided you use enough of it. Of course any petrol spill will turn it into gunk.
     
    Ry Scott likes this.
  4. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,868
    Likes: 878, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Popular remedy in some places, beats having nothing in there, and watching the boat sink, a prospect too horrible to contemplate, I know an old fella who struck a log in a glass boat, it was badly holed, and would have sunk without the polystyrene foam he had installed, saved his life for sure.
     
    Ry Scott likes this.
  5. fallguy
    Joined: Dec 2016
    Posts: 4,451
    Likes: 782, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Lund builds thousands of aluminum boats for the US market, generally.

    My old 1988 Predator has pour foam in the bilge.

    she has only been in saltwater for a week and many flushes since then

    they avoided foaming down the center I noticed to allow for drainage

    Buoyancy foam and enough of it are a way to save lives and must not be minimized. Your boat is a beauty. Make it safe.
     
    Ry Scott likes this.
  6. DCockey
    Joined: Oct 2009
    Posts: 4,930
    Likes: 456, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    Not simple but the methods used for USCG ratings for boats to 20 feet are described in the USCG Boat Builder's Handbook Boatbuilder's Handbook https://www.uscgboating.org/regulations/boatbuilders-handbook.php
    ABYC standards for capacity of boats under 26 feet are very similar to the USCG standards for boats under 20 feet.
     
    Ry Scott likes this.
  7. fallguy
    Joined: Dec 2016
    Posts: 4,451
    Likes: 782, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I don't profess expertise on capacity ratings, but it is all weight based; not based on the number of seats Ry.

    If you remove more weight than you add back; you gain capacity. The boat appears to be built a bit heavy to me. I would venture a guess that if you took a collective review of many other 20' aluminum boats; you would find most of them rated for 7-9 persons...and I would sort of assume you fall on the low end. I would say if you go no rating plate; you would probably get away with 7.

    If, on the other hand, you added weight in excess of original; then 4 is right.

    Things like the deck are big. If you install a 3/4" ply deck; that is super heavy and reduces headcount.
     
    Ry Scott likes this.
  8. Ry Scott
    Joined: Apr 2020
    Posts: 11
    Likes: 3, Points: 3
    Location: Kansas

    Ry Scott Junior Member

    Based on coast guard formula an 8' wide by 20' long boat has a capacity of 10 people at 160 lbs. But all I need seating for is 6 people so either way we should be good.
    As far as the pour foam...it sounds like the way to go but WILL NOT DO IT if it causes problems. It sounds like there are more possible negatives than positives. So I guess I'll go with a sheet foam. I do feel like I wong get the buoyancy factor that I would have with the poor foam tho. Bummer
     
  9. fallguy
    Joined: Dec 2016
    Posts: 4,451
    Likes: 782, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I think you are required to get a rating plate...not sure how...
     
    Ry Scott likes this.
  10. ondarvr
    Joined: Dec 2005
    Posts: 2,611
    Likes: 372, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    I really like what pour foam did for my boat, but would do it different next time.

    You can still use pour foam, use plastic garbage bags, lay them down in the hull and fill them with foam. Put a board on top so the height is right. You could use a sheet of plastic too.

    This gets most of the good aspects of pour foam, but it can be pulled out at any time. Also the foam can be raised up slightly off the hull for an air space.

    Many other foams aren't fuel and oil resistant, so they don't work well in the bilge


    .
     
    Ry Scott and fallguy like this.

  11. Ry Scott
    Joined: Apr 2020
    Posts: 11
    Likes: 3, Points: 3
    Location: Kansas

    Ry Scott Junior Member

    That's a great idea
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.