Tear into swim platform or not?

Rick K

Rick K

Member
Aug 4, 2010
398
Niagara River, Tonawanda, NY
Boat Info
'81 SR245 - '87 Antigua
Engines
260 Merc
Well, it's that time of year, when the shrinkwrap comes off, and I begin whispering sweet nothings at my boat! Noticed my swim platform brackets were cracked, so I pulled the platform. Then I noticed that I blew my back out lifing this thing!

I knocked out the bolts and saw that there was rotted wood and am now wondering if the entire wood core is rotted. Cut a small sample out around the holes, and the wood is wet, but not rotted.

Trying to figure out if the wood core is saturated just by the weight of this thing. It's 84"Wx20" deep, fiberglass. Anyone know how much this thing shoudl weigh?

Repairing the core is no big deal, just wondering if I should seal it up and go, or tear into it now while it's early in the season...

Thanks!
 
No idea what it should weigh but it most likely has plywood for strength with fiberglass outside. If the wood is wet you must dry it out then seal any holes properly. If the wood rots you'll have to throw it away as it will not be safe to use.
 
Thanks for the reply Ken. Was thinking that if it was soaked - it'd obviously weigh a ton. If just wet, it wouldn't weigh as much.

Seems like there's a wood core on the front and rear, where all the brackets mount. I could cut the glass out, pull out the rotted wood, replace it and glass it back in. There's a thread in here somewhere showing how someone did it, but I can't find it for the life of me.
 
That was me that rebuilt the platform on an '89 300DA. There are some pics in my album. I don't know what they should weigh, but they are heavy even after you install dry wood. Mine was wet and some parts were rotting due to unsealed holes drilled by previous owner. The outer skin (underside) was pulling away from the core due to freeze damage I think. I cut of the back skin and found the entire core soaked. I was able to remove all the wood with a putty knife, hammer and my bare hands. If you know the wood is wet, now would be the time to do the recore. A word of caution, while I was grinding the leftover wood and uneven glass from inside the platform shell, I noticed there were some voids in the factory layup and only gelcoat was covering the core. I found this out the hard way when I looked down and could see the ground thru the platform. I wound up regelcoating the entire upper surface of the thing including new nonskid. I have some threads running on this as well as pics of my finished platform. We are going to reinstall it this weekend. It will be a two person job due to it weighing about 150 lbs. I probablly went overboard with the biaxial glass and epoxy, but the back skin was really thin before. Its much stronger now than when it was new. Feel free to ask me any questions you may have.
 
Scorpio, nice boat! My platform is roughly 75-80lbs, but doesn't have a solid plywood core like yours - just wood along the lengths of the front and back. Mine isn't the original either. I spoke with the P.O. last nite, who owned the boat for 25 years before I came along. It was on there when he got it. There were cuts made along the back edge, so that it would mount properly to the brackets. But, whomever did it forgot to seal those gaps, and now we have a problem. I guess after lasting 25+ years, I can't complain!

After doing some more research, I think this will be an easy repair. I'm going to use a 2 part adhesive along with mat, etc., to make the repair. I can't see this taking much more than a day plus layup time. I'll have the admiral snap some pics as I go.

Thanks again
 
:smt038We love pictures !
 

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Well, got into it pretty good, got all the rotted wood out, all cleaned up, etc. Got a lot of pics but have to coax my computer into reading my camera. More to come...
 
That looks like a whole box of bodymans tools! The project looks good, I'd put a heater on the damp wood you don't remove. Are you going to biscut join the new plywood to the old?
 
Well today I took my first step to rebuilding my swim platform, I weighted it....it weighs 110 lbs. I wanted to start this a week ago since the weather has been so nice but..... We tore the floor out in the kitchen and the main entrance and we are putting porcelain tiles down. Another 3 days and the house should be back to normal. Tuesday, I start cutting the swim platform, should only take me a week or so to do this project.

Not sure if the weight will help you but now we know what they weigh on a 300.

Ken
 
88dancer300 said:
That looks like a whole box of bodymans tools! The project looks good, I'd put a heater on the damp wood you don't remove. Are you going to biscut join the new plywood to the old?
Click to expand...

Nah, no bodyman's tools... I couldn't figure out how to put captions on the pics, but I just wanted to show which tools I used to tear into the job. I cut back a bit farther than necessary, so that I can overlap the top piece into the existing wood. The rear edge is double stacked, so I'll glue those together with a product called GL-15 Marine Epoxy Adhesive that I've been using for 10 years or so. It's indestructable once cured. After that, I'll mat/epoxy resin everything, finish, then reinstall. The platform was MUCH lighter, just after removing that little bit of wood.

I'm pondering what to use for replacement wood: Mahogany, Oak, Plywood, etc. Once it's encapsulated in that adhesive and epoxy resin, water intrusion won't ever be an issue.

All this, because whomever installed it way back when didn't have the insight to pop a little 5200 in each hole. They did on the transom, but not on the platform. Go figure...
 
I think plywood is the most economical option, strong also.
 
That's what it was made out of, so I'll probably go with that. I don't know who manufactured this one, but it's constructed poorly. The plywood core consists of pieces that appear to just be laid in shell, then fiberglassed in. Why wouldn't they just use one solid piece, unless they were trying to keep mfg costs down.
 
Mine was pieced also. I was going to try a single piece or even two pieces but the shell is so irregular I had to use several small pieces to get it to fit in and lay flat. I used so much glass on the rear skin those pieces will never go anyhwere. I used over two 12'x38" rolls of the biaxial cloth backed with mat done in a single wet layup with epoxy. My platform had a slight warp when I started so I clamped it to large wooden pallets and then made a stiff back skin so it wouldn't twist when unclamped. Worked great, straight and flat, but heavy.
 
So you used bi-axial? I was pondering what to use. The exposed wood is drying nice and quick, but I'm going to give it till next weekend then complete the repair. I gotta get this done; I opened the boat and had to go up and down a step ladder and with no platform on the back, it was a huge pain! Lugging 3 batteries up and getting them on the boat was terrible...:grin:
 
Well, platform is 99.9% done, just have to do a clean up and it'll be ready to go back on. Will post up some pics of the completed project. In the meantime, I'm looking for some new braces for the bottom. The attached pic is pretty much what I'm looking for, only mine are 26" long, and have 2 holes drilled on either end - and of course bent at the angles to match my boat.

Mine are cracked from wear 'n tear, right where the tubing flattens out, and apparently welding stainless is a project (or so I'm told) and it'd be easier to just buy new ones.

I'm going out of my mind trying to find these with the 26" length. Anyone have any ideas?

Thanks
Rick
 
Just get some stainless rail tubing of the appropriate size you need and cut to length and then flatten in a large vise or hammer flat with a BFH on an anvil or suitable surface. Then bend the angles you need in a vise, it won't take much to bend it once flattened.
 
I was thinking about that, but tried it with aluminum tubing first. When I flattened it in my vice, it ended up cracking. Figured that the stainless tubing would do the same thing (maybe not though?) and before I dropped the dough on that, I'd just try to find ones with the right length. Do you think that the stainless would crack?
 
I going to buy the stainless tube get the angle I want grind the ends of the tube to the angle of the transom and swim platform and then take the tubes to a SS welding shop and have them tig weld 2 small plates on to the ends of the tube. There is a SS welding shop not far from me the guy said $10.00 a tube.

Ken
 
A little heat on the ends of the tubing will maek it more malleable but will turn it blue. You would have to buff that hard to get it out. I've done it in the past with smaller 1/2" SS tube and it worked OK. If you have a weld shop nearby, what Iprof suggested would be a good idea, its not a big job for a shop with some tools and basic skills. I would be careful with fixed ridigid angles welded to the ends, if they don't have enough flexibility they won't line up right, you need a bit of wiggle room to get the platform lined up when installing. Once the tubeing is bolted to the platform and screwed to the hull, the resulting triangular shape of the two pieces unitized is amazingly strong.
 
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