A little help needed

Im working on a project hull right now and im wondering if i should continue with it. this 23' steury hull is a 1979 center console ex marine assist boat from the west coast. The glass hull looks in great shape...But.. on the transom which held a o/b had 3 ss 3/4 skrews in a line verticaly which were not holding anything. as i tapped the transom to listen for blisters in the glass, i found a dead spot. Its about 10" around. The transom has three boxes ahead of it with scuppers and and an box for infont of the o/b for controls and wiring. The marine grade ply that the skews where skewed into from the outside looked dry after dilling out the holes left by the skrews but the fiberglass was delaminated and holding water which drained out after removing the skrews. The transom is strong, i can bounce on a 4x4 wedged into the center box the center box to replicate a bouncing 200 hp without any separations at the seams or flex in the transom. i guess my question is can i inject epoxy into the void after drying it out, press it together and not have to worry about redoing the transom from inside. Any ideas would be appreciated

 

The proper solution is to take the damaged wood core out. Usually you cut from the inside of the boat. However, if you can determine that the core is good, it can be epoxied together. The problem is to be able to dry the plywood. A tent with a heater and dehumidifier would help. Use a moisture meter after to make sure.

 

thanks, I probably should take out the core but the deck and stingers seem solid. With the wood that came out of the core in each skrew hole, it was dry. with a compressor and a blowgun air goes through the blister, i was thinking of a heat gun and time to dry out the blister. and epoxy in a syringe in the bottom hole till it comes out the top hole, massage it around then clamp it together for 48 hours then glass the holes and finish. do you think the heat would cause damage to the rest of skin? sorry to sound like an amature. this is my first project boat, im not to sure what you can do and not do to fiberglass. these forums are probably for the more experienced boat builders and restorers.

 

No no, you are right here. Just be patient, more members will chime in and advise you.

Meanwhile use the forum search function and look for "transom repair" you will have some reading for several days.

Regards
Richard

 

It is difficult to tell without seeing the boat. It may just be a void or delamination that can be repaired. However, drying all the water off the plywood is hard. If you leave it there, the core will eventually rot. Can you cut the laminate and then repair it? If there is an outboard installed, it will cover the repair.

 

The first thing is to determine the extent of the damage, if any. From what you said above you know about tapping the hull. So get a small hammer and start tapping in a grid patern on the transom. Draw the transom on a piece of paper and put a grid over it. Then start tapping. mark on the grid where it sounds solid and where it doesn't. Then go borrow or rent a moisture meter and do the same thing. Be aware, two differwnt meters will give you different readings so mark down the readings and compare them only to each other.

Hopefully this will give you some idea of the amount of water in the transom. If it is a small area, cut it out and repair it. If it is a large area then you will need to replace the entire core.

 

If you have an area as large as you mentioned, it's pretty likely that the entire core is at least overly damp and a good portion is too far gone to dry out.
It's easy to do a map by drilling test holes on a grid of 4x4 inches or so. Light wood color and wet or damp is usually going to be okay after drying but any dark wood should be replaced.
Another thing is once half (or even less) of the transom is found to be in need of replacement, it's a no-brainer that it would be more cost effective to remove and replace the whole thing.

 

Thanks everyone, much appreciated. i will let you know how it goes.

 

Every transom I've repaired (lots) the owner has always said they don't think it's that bad. Then I exposed the core and ask them to come over for an inspection. In almost every case the core is soaking wet, delaminated and badly discolored from mold, rot and moisture damage. Once the core gets damaged, you can't dry it out and pump it full of plastic, it just doesn't work that way. You can kid yourself and dry the surface of the core and hope for the best, but it's still weak and likely to fail.

The core can be remove three ways; from the outside, which requires an external repair and finish; from the inside, which usually means hacking away other things like the sole and stringers in the process, but the external skin remains intact; or lastly from above, between the inner and outer skins, which is a lot more difficult to do, unless using a pour in type of repair.

As you can see each repair approach has draw backs and issues. The "from above" approach can leave the hull shell and the liner intact, but the deck cap might need to be cut and you'll have to remove the core though a 1.5" or so slot, which needless to say is painful to say the least. Also the pour in repair isn't cheap and frankly I don't trust it.

The "from the outside" approach is simple, you literally cut the face of the transom off the boat (leaving a flange of course), exposing the core. I use this method more then any other. This is because the boat that needs this type of repair, is usually in need of a paint job anyway and the hull shell at the transom is often chipped, full of spider cracks, oxidized, etc., so a paint job isn't unreasonable. This method eliminates the need to rip up the aft portion of the sole or screw with the stringers. On the other hand you have to bond the transom skin back onto the boat, fair it in and match a paint job to the gel coat.

Lastly, "the inside repair" is one that is used when you can't convince the customer it's okay to cut the outer transom or the sole and stringers also need attention. There's a lot more cutting and hacking with this approach. You have to work around things and you have to remove more stuff from the boat. There's more 'glass work to make this repair work, but when you're done, you have the same faded gel coat on the transom, that was there before the repair. To some people this is important.

In my way of thinking the fastest means to the end is the way to go, so I usually talk them into a paint job on their transom and hack the outer transom skin off, which usually takes about a half hour with a reciprocating saw.

The simple test to determine if the core needs to be replaced is lock the outboard in the down position, then grab the lower unit and lift, while you look at the through bolts and engine clamp, where they hit the transom. If you see movement, denting, puckers or here noises, etc. you need a new core.