Heres the question. I have an older Maycraft 17 skiff. There are a few soft spots in the floor. I dont want to do a rebuild on this as of yet but I dont want the soft spots either. Can I get a spay structural closed cell foam and shoot it under the floor after drilling a small hole. I know its not permanent But may get rid of the soft spot. I use this boat in a creek mainly so its not beat up on too much.
Jeff
Yes you can do that, but you better be careful…too much foam and not enough places for its pressure to escape and it could lift the floor off of the boat. It’s some seriously strong stuff.
If I were you, and going to try it, I’d use a 1.5" hole saw or similar and take out where you want to fill and another spot where you want it to escape…save the plugs from the hole saw and use them to patch your holes.
Just remember if you put expanding foam in, it has to have somewhere to expand to…or it will expand your parts.
Wadmalaw native
16’ Bentz-Craft Flats Boat
I’m no expert on this but perhaps Sean or Larry will chime in. I don’t think it will hold up. If the glass has already failed, it will still flex some even if you get the foam up underneath it. It might start flexing a little, then a little more, then more, until the foam is compressed to where you were before you shot the foam underneath. At that point when you do decide to do it right, you probably have now created a bigger mess under the floor that if you had “done it right” the first time. Not trying t “burst your bubble”… but I think we all have seen enough “band aids” not work the way we thought they would and regretted the outcome later.
“Ships and Sailors Rot in Port”- Admiral Nelson
As for the fix. it may work or not! Depends on the foam you use! I once replaced a house door and used the wrong foam. There is a foam that keeps expanding and a foam that stops expanding when it reaches resistance. I used the wrong kind and bowed the door frame. Make sure you check it out:smiley:
You need to fix the core, as that is what failed. Cut the top glass around the soft area and expose the wood. Grind all wood out until you hit the bottom layer of glass. Bond new material to bottom glass. Tab top layer of glass. Put a layer of 1708 on top. Fair. Non-skid.
Tall Sail Marine
X2 on what Loop said.
Fix it right now and no worries later.
218WA Sailfish
200 Verado
The "Penn"sion Plan
If you don’t fix the core it will only get worse
Tall Sail Marine
i am sure it will just not ready to do a rebuild on it. its really not bad and hasnt changed over the last couple of years .
Depends on the value of the boat and expected life span you want for it but there are a lot of options from 20$ to $$$$ but a ghetto cheap fix is just put a few layers of new fiber glass. If its structural parts like a stringer or transom you need to do a real repair but if its just a soft spot no biggie to me. Check for structural things like deep stress cracks unusual hull flex. I’ve known people who had soft spots in there boats for over a decade that never changed. Most of the time a soft spot has a source like a leaky mount or screw of some sort. If your boat seems slower or heavier you should drill and drain before you fix the floor as well as the source of leak or you will be back in this situation. If you got bumps, blisters or warping on the bottom of your hull you are far along and have entered the danger zone and should likely look into a new hull. What hull is it? Older hulls had foam that looses its integrity after years and get spongie as they break down.
Pics might help.
If you’re not going to do a quality fix - and -
if the boat is generally safe and usable - then -
I’d just use the boat.
If it needs repair soon, I would think hard before blindly shooting foam in holes. You may block drainage passages or glue wires and such in chase ways that you may need to pull out at some point. Hard to know where the foam goes and what it glues together or shut. As others have said, if you inject more foam than will fit in the cavity you can do some real damage. It can create a LOT of pressure and can generate a LOT of heat when it expands. I’ve monitored 2 lb / 2 part foam while expanding and seen it go well over 150 degrees F. If you do that around a fuel tank, you could have some unexpected results.
17’ Henry O Hornet w/ Johnson 88 spl
26’ Palmer Scott project hull
14’ Bentz-Craft w/ Yamaha 25
1994 May craft 1700 skiff, so its not worth a bunch but a pretty good little boat… Its pretty much been that way for rthe last 5 years when I got it. No change was just looking for slight improvement. maybe I should loose a few pounds and I wont notice it…HAHA. No cracks, blisters. seems as fast as always 30 mph on a 48 evinrude.
I’m certainly no expert, but I’m in the process of rebuilding my boat, and in my opinion there’s no patch job that’d be worth the trouble.
Again I can only speak of the experience I have with my boat, and with it there were a few soft spots, which I thought I could patch by cutting out and replacing wood and glassing over. I was wrong.
After drilling a few holes I found that the foam was soaked, which caused it to swell like a sponge. The floor was attached to the stringers with nails, so when the foam swelled it pulled the nails loose, letting water into the stringers and causing the spongy feeling in the floor. So the stringers were rotten, but the glass around them was still pretty solid.
The boat probably could’ve lasted a lot longer the way it was, but I just couldn’t stand not knowing how structurely sound it was.
So my suggestion is, if you don’t wanna rebuild it or pay someone to rebuild it, use it as is and save up for another hull.