Page 1 of 2 12 LastLast
Results 1 to 20 of 23

Thread: Adding flotation to a 14' aluminum skiff

  1. #1

    Default Adding flotation to a 14' aluminum skiff

    recently I bought a 14' skiff (listed as a 16' but that was mistaken, no big deal I looked at it and it was the size I wanted). It is a 1961 Arkansas Traveler with 0 built-in flotation; no foam anywhere, the seat bench base is not even boxed but a single sheet of aluminum on the front and a piece of wood in the middle of the back to hold them in place. This is the thing; I enjoy pushing the limits of his equipment but I'm still not stupid about it. I'm not about to push a boat that can't float swamped.

    This is what I'm thinking about doing, please let me know what you think. For starters I'll put a floor (1/2" marine plywood floor with added support, Rhino lined both sides or similar if that's too expensive) and fill the cavity with foam. That won't get me anywhere near the flotation that I need. Rather than stuffing foam under the seats and nose I'm thinking about welding the walls with aluminum and making waterproof(ish) compartments topped with marine plywood and hatches. That way they won't swamp and should give me time to deal with too much water inside the boat. I would keep a channel on the center line so water can flow to the currently non existent bilge pump. On the back compartment I figure I could put in a hose higher up, sticking out, pointing back, so there is no vacuum starving the engine of gas. I don't think I can make that compartment that tight, but better safe than sorry.

    I don't expect the compartments to be 100% water proof but I'm aiming to buy me a lot more time than them not there followed by a combo of swamped-sunk. I'll do the framing for the walls with aluminum (I have some nice C-channels) to save weight and for lifespan. Also, will adding the walls as thick sheets of aluminum, thus making the boat more stiff, affects anything?

  2. #2
    Sponsor potbuilder's Avatar
    Join Date
    Apr 2006
    Location
    Palmer
    Posts
    4,360

    Default

    unless you can make the foam on the bottom of the boat totally waterproof the foam will be water soaked(and very heavy) in a short time. In my opinion all the extra metal you'll be adding will just add a lot of weight to a small boat. Buy yourself a good exposure/float suit to wear while running around and have a survival suit stashed on board for when your " pushing the limits of his equipment" in a 57 year old tin boat.

    Alaska Shrimp Pots

    Rigid & Folding Shrimp & Crab Pots
    Electra Dyne Pot Haulers
    Ropes, Buoys, Bait
    alaskashrimppots.com
    akshrimppots@mtaonline.net
    907 775 1692

  3. #3
    Member sayak's Avatar
    Join Date
    Jun 2006
    Location
    Central peninsula, between the K-rivers
    Posts
    5,915

    Default

    I believe I read that Howard Hughes filled the wings of his Lockheed Electra with thousands of pingpong balls for his over-water flight. Believe it was him, or some other old time pilot. Not a bad idea.

  4. #4

    Default

    Quote Originally Posted by potbuilder View Post
    unless you can make the foam on the bottom of the boat totally waterproof the foam will be water soaked(and very heavy) in a short time. In my opinion all the extra metal you'll be adding will just add a lot of weight to a small boat. Buy yourself a good exposure/float suit to wear while running around and have a survival suit stashed on board for when your " pushing the limits of his equipment" in a 57 year old tin boat.
    It doesn't sound like you are getting where I'm coming from.

    I just measured a 7' length of the C channel aluminum I plan on using, it came at 4 ounces per linear foot. If i went crazy with the reinforcing that would be around 8~10 pounds. The aluminum panels would not add that much more. The marine plywood would add a significant amount, but then again people modify these boats with 2x4 and an ungodly amount of 3/4" decking and they don't seem to be having much problems with their boats. Adding 60~75 pounds to the boat (It already has 3/4" plywood seating which I'll make lighter) seems a very fair trade-off in exchange for not sinking.

    Also when I say pushing the limit I'm not talking abusing the living **** out of the poor boat (riding it full speed smacking the waves and such). You could say I push the limits on my backcountry gear snowboarding, or my bicycles when I do a century unsupported and need to deal with whatever breaks 40 miles out (coincidentally a 1967 Schwinn Paramount). I'm on a bay on a supposedly nice day that just turned nasty I just rather be on a boat that floats even if swamped.

  5. #5
    Sponsor potbuilder's Avatar
    Join Date
    Apr 2006
    Location
    Palmer
    Posts
    4,360

    Default

    do a search of the problem Hewescraft's have with foam soaking up water.

    Alaska Shrimp Pots

    Rigid & Folding Shrimp & Crab Pots
    Electra Dyne Pot Haulers
    Ropes, Buoys, Bait
    alaskashrimppots.com
    akshrimppots@mtaonline.net
    907 775 1692

  6. #6

    Default

    I looked for a while but could not find the specific post. Do you happen to remember what they were using? It would be appreciated. The specifications for marine flotation foam are quite stringent but some folks out there are using whatever they find at the hardware store that foams. Polyurethanes are tough materials, they stick like glue to surfaces (a reason why they are used as glues) and on a skiff I would think that any standing water would dry before it gets a chance to do much of anything.

    These are the standards for products marketed for flotation: http://newboatbuilders.com/pages/33CFR_Flotation.html

  7. #7

    Default

    I appreciate your enthusiam for modifying an old boat but it sounds like a tremendous amount of effort for a marginal result. Remember that any floatation you have has to withstand all the upward force when forced under water, that can rip out poorly atttached floor boards and such. Also for the best floatation of a swamped boat you want the floatation higher around the edges instead of in the floor where it may want to capsize the boat. Maybe consider attaching tiedown points along the gunwales and strapping the calulated number of pool noodles to that. They are cheap, replaceable, and visible if deteriorating. Floatation is a nice thought to improve safety but if you are in conditions rough enough to swamp the boat the chances of you being able to bail it out and continue on your way are minimal, you'll be cold, wet and exhausted, but still floating. So that leaves you with adding and stowing a survival suit aboard in addition to all the floatation work and expense.

    For a boat that size, I'd stay close to shore and wear a drysuit and good lifejacket, with an Inreach, flares, and firestarter in the pockets.

  8. #8
    Member KenaiFly's Avatar
    Join Date
    Aug 2008
    Location
    Girdwood, AK
    Posts
    59

    Default

    You might try cutting blue board insulation to fit in sections under the bench seats. Think 'vertical'. Try to keep it off of the hull so things drain away to the bilge and you avoid corrosion. All you are trying to do is displace water with encapsulated air. Problem with ping pong balls is that the space between them is about as much as space in them, so it takes many of them. So, if you are super concerned with displacing the full weight of the boat with flotation, you can also add some blue board around the sidewalls and cover with your new plates of AL material.

    On a boat of that vintage, I would be more concerned with the rivets leaking and just wear a mustang suit with good boots. If you really want to push it, get a dry suit and take a mask with snorkel. That's always good for small craft advisory fun. Good Luck!
    PolarMarine.net

  9. #9
    Member 4merguide's Avatar
    Join Date
    Feb 2012
    Location
    Kenai Peninsula, Alaska
    Posts
    10,557

    Default

    Last summer I bought an older 18' StarCraft. I still have an 18' Valco Bayrunner that I ended up stripping because I needed to replace the the transom wood. When I stripped the Bayrunner I found a few large pieces of foam that were totally waterlogged and weighed more than I could believe. While I was deciding to work on the Bayrunner, I found the StarCraft and bought it basically just for the near new yamy 50. When I was talking to the old boy that sold the boat to me he told me that the original owner had spray foamed the hull. Of course I didn't like hearing that, but like I said, just the motor was worth the price of the whole boat. The StarCraft is a riveted boat, in good shape, and hardly leaks, BUT the first time I put it in the water I noticed how heavy it was compared to the Bayrunner. I'm pretty sure that foam is soaked. Waterlogged foam does not dry out like you think it would. This spring, if I have time, I have every intention of pulling the floor boards and removing every bit of foam from that boat. I recommend you listen to what has been said about foam in boats. If you do a search there is another thread here on the forum about aluminum boats and foam...
    Sheep hunting...... the pain goes away, but the stupidity remains...!!!

  10. #10
    Member 4merguide's Avatar
    Join Date
    Feb 2012
    Location
    Kenai Peninsula, Alaska
    Posts
    10,557

    Default

    Quote Originally Posted by KenaiFly View Post
    You might try cutting blue board insulation to fit in sections under the bench seats. Think 'vertical'.
    I know they "say" that blue board won't absorb water but I wonder if it's ever been proven....I mean over time?
    Sheep hunting...... the pain goes away, but the stupidity remains...!!!

  11. #11

    Default

    Quote Originally Posted by 4merguide View Post
    I know they "say" that blue board won't absorb water but I wonder if it's ever been proven....I mean over time?
    I just weighed and sunk a chunk of blue board in a bucket of water...will re-weigh and report back in April. My Porta-bote has closed cell foam sheet on the side walls...its only about an inch thick x about 8" wide but will hold the boat level fully swamped. Something like that could give the op some added security with only a minimum weight penalty.

  12. #12
    Supporting Member iofthetaiga's Avatar
    Join Date
    Oct 2009
    Location
    Tanana Valley AK
    Posts
    7,701

    Default

    Quote Originally Posted by 4merguide View Post
    I know they "say" that blue board won't absorb water...
    That's absolutely false. I can guarantee it.
    ...he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. ~Thomas Jefferson
    I would rather have a mind opened by wonder than one closed by belief. ~Gerry Spence
    The last thing Alaska needs is another bigot. ~member Catch It

  13. #13
    Member
    Join Date
    Sep 2014
    Location
    Alaska
    Posts
    502

    Default

    I think, since you asked, that both of those operations are a bad idea. The below deck foam will soak and welding on 1961 aluminum skiff is a dubious task at best. You've been given the best advice which is wear a good work suit while at sea in your new pride and joy.

    No offense meant. Been around boats quite a bit. That water is real cold around here.

  14. #14
    Member 4merguide's Avatar
    Join Date
    Feb 2012
    Location
    Kenai Peninsula, Alaska
    Posts
    10,557

    Default

    Quote Originally Posted by iofthetaiga View Post
    That's absolutely false.
    What....that it won't absorb water, or that they say it won't absorb water...??? Is the pink stuff different than the blue?
    Sheep hunting...... the pain goes away, but the stupidity remains...!!!

  15. #15

    Default

    Quote Originally Posted by 4merguide View Post
    What....that it won't absorb water, or that they say it won't absorb water...??? Is the pink stuff different than the blue?
    Just about every 'rigid' foam that man has created will absorb water, over time. For sometime, it was popular to build houses with a pink or blue or white polystyrene apron placed horizontally around the foundation to get around having a proper footer in frost zones. It's quite remarkable how much it weighs when dug up twenty years later! The least absorbent is expanded polyethylene (pool noodles).

  16. #16

    Default

    Quote Originally Posted by dbcooper View Post
    recently I bought a 14' skiff (listed as a 16' but that was mistaken, no big deal I looked at it and it was the size I wanted). It is a 1961 Arkansas Traveler with 0 built-in flotation; no foam anywhere, the seat bench base is not even boxed but a single sheet of aluminum on the front and a piece of wood in the middle of the back to hold them in place. This is the thing; I enjoy pushing the limits of his equipment but I'm still not stupid about it. I'm not about to push a boat that can't float swamped.

    This is what I'm thinking about doing, please let me know what you think. For starters I'll put a floor (1/2" marine plywood floor with added support, Rhino lined both sides or similar if that's too expensive) and fill the cavity with foam. That won't get me anywhere near the flotation that I need. Rather than stuffing foam under the seats and nose I'm thinking about welding the walls with aluminum and making waterproof(ish) compartments topped with marine plywood and hatches. That way they won't swamp and should give me time to deal with too much water inside the boat. I would keep a channel on the center line so water can flow to the currently non existent bilge pump. On the back compartment I figure I could put in a hose higher up, sticking out, pointing back, so there is no vacuum starving the engine of gas. I don't think I can make that compartment that tight, but better safe than sorry.

    I don't expect the compartments to be 100% water proof but I'm aiming to buy me a lot more time than them not there followed by a combo of swamped-sunk. I'll do the framing for the walls with aluminum (I have some nice C-channels) to save weight and for lifespan. Also, will adding the walls as thick sheets of aluminum, thus making the boat more stiff, affects anything?
    If I was you, I'd abandon whatever it is (frankly, I don't understand exactly what the heck you are aiming at) that you are try to do and just reconfigure it to original condition; gauge material containers for ANY flavor foam under seats - done! Unless its submerged 24/7 you don't have to worry about the foam as it normally 'should' be above water. You just can't make your dreamliner out of this thing:
    Attached Images Attached Images

  17. #17
    Member sayak's Avatar
    Join Date
    Jun 2006
    Location
    Central peninsula, between the K-rivers
    Posts
    5,915

    Default

    Quote Originally Posted by copperlake View Post
    Just about every 'rigid' foam that man has created will absorb water, over time. For sometime, it was popular to build houses with a pink or blue or white polystyrene apron placed horizontally around the foundation to get around having a proper footer in frost zones. It's quite remarkable how much it weighs when dug up twenty years later! The least absorbent is expanded polyethylene (pool noodles).
    Makes me wonder what the weight would be for the foam on all these trailers and other structures that have been coated with spray urethane as an "after the fact" insulation measure.

  18. #18
    Supporting Member iofthetaiga's Avatar
    Join Date
    Oct 2009
    Location
    Tanana Valley AK
    Posts
    7,701

    Default

    Quote Originally Posted by 4merguide View Post
    What....that it won't absorb water, or that they say it won't absorb water...??? Is the pink stuff different than the blue?
    The pink stuff and the blue stuff will both absorb water, just like the white stuff.
    ...he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. ~Thomas Jefferson
    I would rather have a mind opened by wonder than one closed by belief. ~Gerry Spence
    The last thing Alaska needs is another bigot. ~member Catch It

  19. #19

    Default

    Box the seats and install pool noodles to fill the cavity. Bow also if possible. Nothing under floor except open cell foam.


    Heavy Hitter Fishing
    https://www.facebook.com/pages/Heavy...54441957966186

    Kodiak Custom Fishing Tackle Pro-Staff


  20. #20

    Default

    I just gutted the below deck and bench foam out of my 16' G3. Totally waterlogged and it was only 7-8 years old. Ended up lightening the boat by 250lbs. It will now sink nice and proper if I swamp it...

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •