19-1 transom rebuild

[Xjbob99]

Well. Its time. i pulled a little section of my transom cap off and sure enough its really rotted and the fact that it flexes like crazy told me its junk. Im going to start tearing into it tonight. going to try to get the whole gunwale cap off to save me time in fiberglassing the cut sections back in.

here is a picture of the boat. ive had it out once fishing and i love it so far.



and here is a picture of the transom cap ripped off



hopefully i can get everything ripped out this weekend and get a material list for Monday and get some stuff on order.

[Xjbob99]

Here is the layup schedule i have in mind so far.

get it all down to the old skin and cleaned from there it will go as follows

1-lay down 2 layers of 1708 and 1 layer of 3/4 CSM
2- make the new core, 3/4 marine ply- 3/4 CSM -3/4 ply lay on flat cement floor and put a bunch on cinder blocks on it and let it cure for 2 days.
3- dry fit new core in and come up with a clamping plan, thinking 4x4's and all thread, then lay a fillet of cabosil around the skin. then use a 1/4 notched trowel and spread the cabosil evenly on the old skin and set the new core and clamp. let that cure for 2 days.
4- fill in any gaps around new core with fillets and then tab in the new core with 1708
5- layer of 1708
6- tab in more 1708
7- final layer of 1708.


let me know if you would adjust any of this? also anyone have a rough estimate on how much resin this would take.

here is a rough list of what i will be ordering:

2 gallons of us composites Epoxy with 3:1 Ratio Medium Epoxy Hardener (not sure if this is too much or not enough yet)
1 set of 3:1 ratio pumps
1708 biaxial need to measure to come up with an exact amount
3/4 chopped strand mat
cabosil
2x 4x8 marine plywood
misc brushes and rollers.

please let me know if you think i would need anything else or if forgot anything!

[Xjbob99]

I ran into a huge snag. It looks some replaced the middle part of the transom. Just the middle and it's a pain in the ass to remove from the outer skin. What are my options here. Should I just cut the whole thing out?

[Levi]

See if you can dam it off and pour boiling water on it that should loosen it up enough to be able to chisel it off relatively easily. I had to do that on the deck of my mako where the plywood was because the balsa was MUSH but the plywood was either dry or mostly dry and WELL adhered. It was easier on a flat surface but I'd imagine if you dammed it off put some rags over it and kept it hot for a couple hours would help loosen the wood up. Chisel crossways to the grain and it will peel off easier and in bigger chunks especially if it's wet.
Clean off what's left with a tigerpaw and a 4" grinder. The $10 harbor freight one works fine and will be your best friend throughout this project they also have the tigerpaws pretty cheap too. This SHOULD go without saying but WEAR SAFTY GLASSES when you use the grinder. I also use a half faced respirator but I'll leave it to you to make that call

[RickK]

Hey xj, I think your layup schedule looks fine 'cept you don't need to tab in the transom core.  Just laminate 3 layers of 1708 in increasingly bigger overlaps onto the hull bottom and hull sides - 4", 8" and 12".  That gives you built in tabs.
Also consider gluing in a foot long piece of 1 1/4" - 1 1/2" ID pvc pipe to the hull bottom aligned with the drain plug.  With all the lams you're adding of 1708 you're changing the low point in the hull to about a foot forward of the transom and you'll always have water pooling there.  With the pipe, you're keeping the low point at the transom so all water will drain out. (Wish I had learned this prior to doing my rebuild)  Follow this rebuild to learn also. http://classicaquasport.com/smf/index.php?topic=13717.msg137297#msg137297

As for your transom core removal, do you have, or have access to an air chisel and a skill saw?  Use the saw to cut the transom core into small strips (make sure not to lower your blade into the skin) and then use the air chisel to peel it off the skin - works great.  Then use the grinder Levi recommends to clean it up to bare glass.  If you don't have an air chisel, try Levi's approach.

BTW, you're going to need to cut the stringers back 18" to give you room to work and do the lams you need.

[Xjbob99]

I tried and tried and tried getting that center piece out that someone put in. I couldn't do it. There was 1/4 piece of metal in there too... I think they cut the transom down and just put in that center piece. There was no outside skin there where that center piece was so I just ended up cutting it out all together and saveinget as much as the regular skin as possible. Is this going to be a problem? Also now that the transom skin is so short so I still go along with my planned schedule and just add some layers to the back????

[Xjbob99]

Alright sanding is going pretty well. Got most of what's left of the outside skin flat and smooth. The side of the hull in the pictures below the inside skin seems to be unattached to the outside of the hull. Should I cut those skins back so when I glass in the core it bonds to the hull then the next layers glass it into that inside skin?
Here's the inside skin Where's it's not attached to the hull


The other side


And does this look good so far

[RickK]

I saw what I thought was metal plate and said to my self - "naw, couldn't be".  Guess I was wrong.


Did you get good measurements of where the notch was?  Should be 20" up from the bottom of the hull.
There are plenty of examples of using some formica covering some plywood to make a nice flat mold to build your transom skin.  Look at Hawgleg's rebuild - he documented that pretty well.

[Xjbob99]

Yeah I measured everything. I believe I have a 25 inch shaft motor. From the drain plug to the top of the transom measured 25 inches

[RickK]

Ahhh, that explains why the transom had been reworked. I think the original was 20".

[Xjbob99]

Yeah. Wish they hadn't. Would of been way easier to remove that rotted stuff

[Xjbob99]

well. materials are on order. should be here for memorial day weekend. found a local lumber yard that has the marine ply. should have the outside skin on next weekend.

[Xjbob99]

Took memorial day weekend off from the boat. Finally made some progress tonight after work.

Set the dam up


Then laid the fillets in and was running out of steam. Hopefully lay the outer skin tomorrow

[RickK]

Nice clean work 
Couple things I would do:
1) cut the dam way down to 6" higher than the finished transom skin height - you want to be able to spring clamp the layers of cloth at the top of the dam and flip the cloth into the boat as you need them.  Clamp the pieces of cloth onto the dam and make sure they are long enough to give you 4", 8" and 12" of overlap on the hull bottom and sides.  Once you have the proper lengths flip all out of the boat and then flip the first one in and trim/pleat it.  Then flip the 2nd one in and repeat, etc.  Then to actually lam them in, flip all out of the boat, roll resin onto the areas, flip the first one in and hard roll, repeat adding more resin as you go.
2) I would glue (using thickened resin like you did the fillets) a 1" ID/1 foot long piece of PVC onto the hull bottom aligned with the drain hole.  Reason for this is that as you build up your new skin lams and then add the core and lam that in, you're actually moving the low spot in the boat out ahead of the transom and now the boat won't drain all the water out (like in mine and others after our rebuild  ).  With the pipe installed, you'll have a way to plumb the water out of the new low spot.  There are a couple examples of following this advice on the site.  I see that you have already filleted over the drain hole - I would drill a hole through that the size of the OD of the pipe and glue the pipe in.

[Xjbob99]

Thanks for the advice rickk i was planing on putting the pipe in. would now the be the correct time? i was going to put it in after i got my 3 layers of biaxial down.