voids in the transom

[andgott]

Re: voids in the transom

It's hard to tell from the photos if the original stringer job was 'factory' or if it was later... Though if I had to make a guess, I'd say it looks like it was probably built that way.

I've seen a number of boats that came from the factory just like that- stringers laid in to the hull, then glassed over, nothing between the hull and the stringers. It seems fairly common in older boats... By 'older' I'm talking 40-50 year old boats. Probably had a lot to do with the 'newness' of FRP construction, people were still experimenting.

I've also seen it in newer boats like yours- Especially in tri-hull boats that had relatively shallow areas under the floor like yours does. It seems that the stringers are there more to support the floor than to add stiffness to the hull, inevitably they had foam filled bottoms like yours does (or did?), and the rigid foam was providing thee structural support for the bottom of the hull, not so much the stringers... When I've torn in to some boats, I have been absolutely amazed at what was done in the factory, especially below decks. I guess it's a case of 'out of sight, out of mind'.

If that is a factory stringer job, and you replaced it in the same way, it could be fine... HOWEVER, I don't see any indication of having replaced that foam down there. In many designs, the foam does more than provide floatation, it is also an integral part of the structure, providing support for the hull.

You can be glad that you ripped that transom out. The fact that you were ABLE to get it out shows that it was not installed even close to correctly- And it shows in the pics! Take some time to read over the transom install threads and info on this site- there is a TON of it... A transom is one of the most critical parts of the boats structure, and MUST be done right!

-Andrew

 

[Toad64]

Re: voids in the transom

Thanks guys. I put the foam back in because it seamed like it would at least help with the stiffness of the boat as well a floatation.

The back outer skin of the boat has a slight bow outward it in when you look down it from the top with the wood out should that concern me to much or do you think the clamping will take care of that.

 

[Yacht Dr.]

Re: voids in the transom

Hello Toad64 ..

I dont think everyone is on the same page as you in describing what your doing/did.

It looks to me that the stringers were built that way.

So just to expand a bit in the dialog ..

1. You removed the stringers out of fiberglass 'sleeves' ? Was the wood capped with fiberglass when you took it out ?
2. You slipped some 2Xs back into the stringers without glue or resin ?
3. Did you cap the wood stringers with fiberglass ? ( Did you encapsulate the stringers/bulkheads with fiberglass and how much )

Just to let you know that I have seen builds that the wooden stringers are just for 'form' for the fiberglass. Yes the stringers were tied into the sole/deck of the boat which was tabbed into the hull.

Not to say the build is wrong or right.. but I see nothing Catastrophic in a boat that only does 30 knots with an OB moving it.

Now if the boat had an I/O .. yea.. WAY wrong to build it this way. But if your transom is built/installed correctly I think your ok to do a fiberglass encapsulated stringer system.

You might want to give a little more information of How you did things other then What you used to build it with.

I could be reading the thread wrong..but I think you Might be in the ok on the stringers as long as you glassed them over.

Let us know ....

YD.

 

[Toad64]

Re: voids in the transom

When i bought the boat the PO had just put treated ply wood in over the rotted out floor and i did not know that. so i was going to replace the carpet and found this out. when i pulled the wood up i found the floor was so far gone that i could use the shop vac to suck up the wood. it had some fiberglass on the floor but it was just laying on top of it. so i started pulling the foam out and got to the point where i had to take the top off because i could not get to any more of the floor with the top on. the area up front where the seating is is a part of the top as is the floor in that section. so i went to a buddies of mine we took off the rub rail, pulled the rivets, then had to cut the top off because they fiberglassed it on at the seam. i finished pulling the foam and the transom and let it sit for a couple of weeks to let the wood dry so i could use the stringers and the bulk heads as templates. the transom came out in 2 pieces. one piece of plywood that was stapled to the one connected to the boat. the other i ground out. so i then got in to pull the bulk heads and they had little nails holding them in so when i pulled they came out. then i grabbed the stringer pulled and it slid out of the sleeve. i thought to myself cool. so i then got the 2x4's, the stringers appeared to made from 2x4's, and traced the old stringers on to the new 2x4 and cut and sanded them like the old ones coated them with epoxy did the same with the bulk heads and slid the stringers back into the sleaves fitted the bulk heads back in they all lined up so it looked good to me. i will say that the bulk heads are sitting off of the hull on what looks like built up PB. the stringers do not appear to be sitting directly on the hull i don't understand exactly how they are sitting but it looks like not on the hull but i considered it luck or design but called it good. then i cut the plywood for the floor fitted it in filled in the gaps with bondo for fiberglass that has the fibers in it. then cored the deck and filled with foam.
now as for the transom i know i messed that up but i PL two pieces ply together and used the piece that came out whole as a template cut it out coated it with resign put fiberglass on it then tried to just resign it in and that was a major failure.
there where other little things i did if you need to know anything else just ask and i will try to answer. I am not a good speller or typest so sorry for all the mistakes.

 

[Toad64]

Re: voids in the transom

let me say this the reason i did what i did was that the stringers and eveything did not look like they where doing anything but holding the floor and all i could find at the time was thing that had to do with plywood stringers.
o and there was no sign of any old restore on the boat, the floor was nailled the stringers and the stringers where not fiberglassed on the top so i did not think they needed to be. just looked like a floating floor.

 

[Woodonglass]

Re: voids in the transom

So you did not glass the stringers back in and or glue them back into the sleeves? What kind of foam did you use under the deck and how did you install it?

 

[andgott]

Re: voids in the transom

Looking at your 'before' pictures of the stringers, they don't appear to be 'stringers' in the sense that we'd usually refer to them on here, more like floor supports. Were they continuous pieces of wood, or are they just short sections? It looks to me that they are butted together where the plywood cross members are.

If this is the case, I tend to think that they are not intended to be 'Stringers', that would provide longitudinal strength to the hull bottom, because of how they are butted... They'd be one continuos length of solid lumber for strength reasons. I've seen it done like that, in trihulls for the most part. The wood is there to provide something to attach the floor to so it's not relying 100% on the foam.

Of course, if that's how it was done, It's CRITICAL that you used the correct foam, it is going to need to provide strength, so it needs to have some rigidity to it. You'd have to use a multi part poured/ sprayed foam, like the builder did.

-Andrew

 

[Toad64]

Re: voids in the transom

AeroMarine 4# Density polyurethane foam
I know it is aeromarine but i think it is #4. i drilled holes and filled the voids.
the stringers run the hole floor but are notched where the bulk heads are.
looking back i know the second order of foam was the #2 which is what i put in the back of the boat i still think there #4 went up front.

 

[Woodonglass]

Re: voids in the transom

In this picture, it appears that these two stringers are one continuous piece of wood. Is this correct?

I will concede to the more knowledgeable Andgott and Yacht Doctor that the stringers may not have been capped at the factory, but I am almost certain that they were glassed and tabbed to the hull due to the "Channels" you found. Due to the rot and the water they were no longer attached when you found them but IMHO the ones you put back in Should have been glassed to the hull and not just left loose in the channels. The only thing holding the deck down will be the tabbing to the sides of the hull on top and I suppose that will be sufficient. The Foam you used is exactly right and if you poured it in until it came out of the holes to ensure all the voids below were filled, you should have as strong of a hull as before. I would have liked to have seen the stringers epoxied to the channels and bedded to the hull and capped off with epoxy and cloth but you did coat them with epoxy so they should last for several years. I apologize for "Freaking Out" just a bit but I had never heard nor seen uncapped stringers but I guess they did exist in the past from the MFG's. What a shame. Glad my name was not associated with building a boat like that from that factory. But maybe they didn't know any better back then.

 

[Toad64]

Re: voids in the transom

Thank you wood (may i call you wood) if i ever have to redo the floor i will do them that way.

 

[andgott]

Re: voids in the transom

I was looking at this view-

And it appears that they are butted up... But It's hard to tell for sure.

I just read this in your earlier post-

The back outer skin of the boat has a slight bow outward it in when you look down it from the top with the wood out should that concern me to much or do you think the clamping will take care of that.

Was the transom curved before you removed the old plywood? Some are built that way, It is "Pre stressed". If that is the case, you want to re-do it with a curve. If it was flat before, it should be flat. If it's only a small curve, you will probably see it disappear when you clamp the new one in.

 

[Woodonglass]

Re: voids in the transom

Ok, I see what you mean. They do appear to be 3 pieces. WOW! Toad, I have to say you have a boat like none I have seen but I have not seen all that many, like Andgott has. He is correct about the bow in the transom, if it was there before it should stay there. You would need to use mulitiple layers of 3/8" ply and bend and laminate them to the shape of the outer skin. If it is a very minor curve then no problem. Best way to tell is to look at the bottom along the hull and the skin. If you lay a straight edge across there and it's curved then you may need to rethink how you are going to build your transom.

Oh and Wood, Woodie, WOG, or Old Dumb Okie, I answer to just about anything.

 

[Toad64]

Re: voids in the transom

The bottom is not curved it starts in the middle and just slightly bows, if i pull on it and the top it comes out. Just thought i would ask and see if it might interfere with the clamping process?

 

[Woodonglass]

Re: voids in the transom

Peanut butter the skin and the wood and clamp her flat!!!

 

[Toad64]

Re: voids in the transom

I have the clamps built. How much PB should i make up the transom is about 64" by 21".

 

[Woodonglass]

Re: voids in the transom

You've got just under 20 sq. ft. counting the transom and the skin. 1/4 to 3/8 inch thick on both. I'd say 2 -3 qts. Use a notched trowel just like they use to lay ceramic tile. Make sure and do a dry run first. You will not have much time (15 - 20 mins.) so you gotta know how everything fits and how the clamps work. don't clamp to hard and squeeze all the PB out. when it starts to ooze out at the top and bottom and aroun the edges Stop and let her set up. Tightening the top bolt put pressure on the bottom of the transom, bottom bolt puts pressure on the top. Hopefully you have 5 or 6 of em to get good clamping distribution. Have a large plastic spoon available to use to create a concave fillet around the edges and along the bottom when the squeeze out occurs.

 

[Toad64]

Re: voids in the transom

I Have 6 of them been messing with them to see how they work. I have not had time to get the transom in yet with spring coming been turning my attention to getting mowers and tractor ready for all the grass that will be growing. then i hurt my knee and pulled a muscle in my shoulder. maybe this weekend but i have Drill so probable not. I will post some picks when i can get back to this project.

 

[Toad64]

Re: voids in the transom

I was wondering if anyone thought these would be a good battery for a boat?

http://oklahomacity.craigslist.org/boa/2838981601.html

when i talked to the guy about them he said they where for back up power for big companies and they cycled them out every 2 years to keep them fresh. they have 550 cca, weight 70 lbs, are VRLA glass mat, and are good for 260 cycles so they are designed for 10 yrs of service. he said he as alot of calls from people wanting them for boats. he could not tell me what the AH would be. When I looked up the specs i could not make heads or tales of what the AH would be.


CONSTANT POWER DISCHARGE CHARACTERISTICS: WATTS/CELL (77?F, 25?C)
End point volts/cell 5 min 10 min 15 min 20 min 30 min 40 min 45 min 50 min 60 min 90 min
1.85V 336 276 235 202 156 127 116 106 92 67
1.80V 388 300 249 212 163 134 123 113 97 70
1.75V 436 326 263 221 171 139 130 117 100 73
1.70V 480 350 274 231 177 144 132 121 103 76
1.67V 506 361 283 236 180 146 134 123 106 78
1.60V 559 384 298 246 185 148 137 127 108 81
All mentioned values are average values per battery per cell.
Tolerance: X <6 min (+15% ~ -15%), 6 min X < 10 min (+12%~ -12%), 10 min X < 60 min (+8% ~ -8%), X 60 min (+5% ~ -5%)

I thought they could not be that bad of a battery?

 

[Toad64]

Re: voids in the transom

I was over tring to set up my clamps and to get out the little bow thats in the transmo skin i have to clamp pretty hard and i am afraid of squeeze out to much PB. I am just wondering if anyone thinks that i will squeeze to much PB or will it even it self out. Also do i need cover the existing hole in the transom skin somehow like put tape over them?

 

[Woodonglass]

Re: voids in the transom

Are you sure the original transom was not bowed? and yes, cover the holes with wax paper and tape. Post some pics.