Formula 27PC Transom Work

[tpenfield]

I cannot get to the other side of the stringer at the back. Formula boxed the very end and installed the hatch lift on one side and the power steering pump on the other. Would a straight butt joint be the way to go or do a 45 degree or something else?

You may want to remove and then rebuild the boxed ends of the engine mount stringers. That will require some additional 1/2" plywood and some 2-part foam (4 lb density).

The key thing at this point would be to determine the extent of the repair area, based on what you find in terms of moisture and rot. It may take you past the engine mount stringers and to a point before you reach the outer stringers. Some of the wood that shows in the pictures is still dark, so you could rationalize going further outward until you reach blonde wood.

A judgement call on what you replace versus what you chemically treat. In my repairs, I have done a bit of both.

 

[Woodonglass]

You might want to consider investing in a multi function oscillating tool. It seems to me it would come in Might Handy for what you are doing. Harbor Freight sells one for under $20 bucks and has all the various blade attachments and it works really well. Cuts thru glass stringers like butter. I think you'd find it mighty useful.

http://www.harborfreight.com/oscilla...8861-8493.html

 

[jc55]

Yes, I'm with these guys. All dodge, that rear layer, the black, is there a chance that it might seem kind of dry but be really "pithy"? I ended up using an electric chainsaw where my boxed fiberglass stringers ran into the transom on my build.

 

[alldodge]

Thanks guys, just had another idea and this way I can get at the wood behind the stringers. In the pic below I marked the stringers and a box to each side of it. What do you think if I cut the outside over this area to get at the wood? Pros Cons??

 

[tpenfield]

I would not cut the outside of the hull. Too many things could go wrong with the repair and related bonding of new to old material, and any failure of the bond would result in a leaking boat. Better to do a little more work from the inside than it is to cut the outside.

Perhaps a creative way to get more of the wood out while avoiding structural cuts would be to get an 'end mill' bit and use a high speed drill and go into the wood from the existing access points until you hit good wood.

When I had to re-do the back-end of my F-242SS (yea, I had to replace a bulkhead on that too, as well as some stringer work), I made some custom cutting tools by grinding down the points on some long reach drill bits. Combine that with a high speed drill and it was like a Dremel tool on steroids :thumb:

If you are able to use a mill bit approach, then a high density pour-in foam maybe a better solution for filling the endpoints of the repair area, using wood in the center for the keyhole area.

Just my thinking 'out loud' . . .

 

[alldodge]

Sounds like some good info. My thread on OSO has Tommy is in agreement with you in no cutting of the skin. States all I need to handle the stress is just to the stringers. Says the total load is taken by the stringers and the bottom of the hull, rest just keeps water out. The big question is how much rot is behind the stringer on the port side. Knock on wood, but I think the starboard side will come out OK. Like the end mill idea, I'll see what I can get done.

 

[tpenfield]

Yup, I checked out your thread over on OSO. Good to get multiple sources of input and ideas.

 

[alldodge]

Just cut about another inch above on both port and starboard sides with my 18V skill saw. Pried the wood off and sure enough it's black behind is also. I'm now half way up to about the top of the stringers. Getting that sinking feeling that a partial replacement is not going to work. I could cut out clear to the top and replace it from the stringers in, not sure that would work either. Thinking there could still be black on either side. Going to sleep on it and think about what it would take to get the whole thing out. :facepalm: :facepalm: :facepalm: :facepalm:

 

[zool]

Mine started out with a small black spot on the port keyhole, I later found rot in areas I wouldn't have though it was, like behind the boxed in outer stringers...its a condensation area, that seems to promote rot. The main thing you need to do is make sure you replace the wood all the way around the keyhole, and a safe distance past the cutout, to maintain integrity. I left the upper portion of the original transom wood, and overlapped(scabbed) the lower portion about 8 inches...if your stringers are good, you can cut them back slightly from the transom, to slide the new piece in...or remove a section of the stringers, and scab new lengths back to the new transom bottom.....its a lot of work, but rewarding in piece of mind....its early enough in the fall to be ready by spring, imo..

 

[Woodonglass]

After all I'm hearing and seeing I'm going to have to refer you back to post #3

 

[bigdirty]

Having some really terrible internet connection issues the last week, first time I've been able to actually log on in a while, but i've been following this thread.. (can view pages, but thats about it) All I an say, is look up my crownline thread, you will be amazed how far the rot can travel.. even thought it may 'feel' like good solid/tough wood, it may just be in the early stages of rotting. My .02$ is in agreement with tpenfield, knock out the boxed in sections in the engine bay for better access, and I'd also plan on redoing the whole transom, as it does look quite soft..

 

[jc55]

Dig in, man. You're going through the 5 stages of transom grief like we all do I would still like to see a bird's eye view of the entire inside of the transom. You'll have this thing knocked out and done in two weeks of spare evenings if you're up to it.

 

[tpenfield]

Yea, the digging stage. . .

The Formula 27PC has over a 9 foot beam IIRC. Access from above is restricted by the upper half of the boat (cockpit/deck assembly). So, if it ends up being a full width replacement, it would probably have to be installed in several pieces of wood. It would be nice if just the center section had to be replaced, as that would be a order of magnitude easier, but not actually easy in any regard.

 

[tpenfield]

Having some really terrible internet connection issues the last week, first time I've been able to actually log on in a while, but i've been following this thread.. (can view pages, but thats about it) All I an say, is look up my crownline thread, you will be amazed how far the rot can travel.. even thought it may 'feel' like good solid/tough wood, it may just be in the early stages of rotting. My .02$ is in agreement with tpenfield, knock out the boxed in sections in the engine bay for better access, and I'd also plan on redoing the whole transom, as it does look quite soft..

Yea, your thread would be a good resource. Did you sell the boat, like you were thinking of doing at one point?

 

[alldodge]

Was having some real issues thinking about all the work, but I also have all winter, (burr) recon I can get it done. The wood is 2 inches think and real solid. The rot is showing on the back side layer only against the outer skin. Just a thin layer but means it is delaminating from the hull. Need to get a multitool so I can have an easier time cutting some of this out. While I haven't done much fiber glass work before, I'll be looking to you guys to steer me along. One good thing is this old guy is retired and has a bit more time to spend. So long as other things don't get in the way. Going to take a trip today to go find some more tools.

Thanks much, and I'll get some more pics for a birds eye view

 

[tpenfield]

I noticed that you have your boat in a building, at least you did when you took the engine out.

Is that going to be available and where you will do the work? You will probably want to get as close to 70 degrees F as possible during the winter, if you will be glassing then.

I am thinking that this will be one of the largest, if not the largest, boat in recent memory to have a transom done.

 

[bigdirty]

Yea, your thread would be a good resource. Did you sell the boat, like you were thinking of doing at one point?

No, didn't sell it in the end, I've decided to keep her, and redo all the seating and 're-engineer' the layout of the helm and back deck area over the winter, and possibly build a custom swim platform extention. And yes, My friend with the 31PC was looking at a 'newer' 27PC a few months ago, I believe they are actually a 9'6" beam..

 

[alldodge]

I noticed that you have your boat in a building, at least you did when you took the engine out.

Is that going to be available and where you will do the work? You will probably want to get as close to 70 degrees F as possible during the winter, if you will be glassing then.

I am thinking that this will be one of the largest, if not the largest, boat in recent memory to have a transom done.

Well got a multitool and a couple extra blades, but late this evening to start up. will hit it tomorrow. This is my pole barn on property but it's un-insulated. I'll work something out, and just like a marriage (better or worst) I guess I'm going to fix it my self.

Bigdirty, yes the beam is 9'6" but this is at midship. The transom area is right at 9'

 

[zool]

My transom was over 9'6 wide, if you cant source 10' marine ply, it can be done with 8' ext ply, by lapping...



To get it in without removing the cap, you also need to shiplap the top....making it the full width and tabbing both sides, hull bottom, and over the top shiplap will give the proper strength you need, been there, done that.





all in all, not that bad a job, but the engine should come out.

 

[Woodonglass]

Hey Larry, I thought You would use one of those East Coast Plywood Stretchers!!!!