transom rot repair

[anchorout]

Just bought a used cd22 and, in drilling to install trim tabs, I found water in the top 6 inches of the transom core. I have read everything in the forum on transom repair (very informative). My question is on the SEACAST repair system. I have seen their repair site and it looks like a good system. HAVE ANY OF YOU ACTUALLY USED THIS SYSTEM? ARE YOU SATISFIED? HOW MUCH MORE WEIGHT DOES THE REPAIR PUT ON AN ALREADY STEARN HEAVY BOAT?

[thataway]

The Seacast will be 31 lbs for 5 gallon bucket--about 3 buckets for a C Dory 22 repair.

Is the moisture only in the upper 6"--have you drilled holes and taken cored samples below this level? Have you pulled the motor and inspected the mounting holes--and under the black plastic cap where the hull to deck joint is joined--and where an upper transom core leak would occur.

Seacast says not to do a partial repair--there will be a hard place between the wood and Seacast. You have to use a chain saw to get all of the old wood out of the transom.

I did replace the transom in a 20 foot Grady White. We used 3/4" marine ply, soaked in epoxy. Epxoy in place--had cut out the old outer transom and saved the glass--bolted it back in place with epoxy for the repair (details if you are interested)--today I might use Coosa board.

To test the intregrity of the transom, put the motor in trailer position and put your fool body weight on the lower unit. If the engine flexes the transom, you need to replace the entire transom.

Sorry to hear about the issue--especially in a boat you have just purchased Maybe the seller will help out. Was there a survey? Moisture meter?

[journey on]

Bob,

Didn't you also rebuild the transom of Frequent Sea, your trip through the C-25 world?

Boris

[thataway]

The frequent sea Transom had a good core, except three small areas in the very bottom. Both sides the screws of the trim tabs and the transom drain has wet wood around the fittings. The amount of wet wood was limited, and we routed it out, and filled with solid fiberglass. The top did not have any moisture, despite the fact it was not finished properly. We re-did the hull to deck joint with a glass wrap and put the cap back on.

The major "transom" problem was the way the splash well supported the forward thrust. We found there was only one layer of matt which was carrying that load. There were "stress cracks--which were significant. We redid the top of the splash well in the way of the transom and then layered several layers of try-axial cloth and epoxy under both sides making it over 3/8" of solid glass.

[jkswor]

I repaired a water soaked transom with products from rotdoctor.com.
Had to completely dry out the wood, drill holes in the transom and fill with a syringe until full , then use fiberglass risen.
Bottom line, did not have to replace the transom, was hard as a new.
Bad news, cost was $500 or more, for the product and equipment, and shipping to Alaska. Had to use a ventilator due to vapors.
Was a major winter project any how, just another option. Would never want to do again.

[Sunbeam]

I haven't used or studied the Seacast system, so I realize I'm replying when you requested those with experience with Seacast. But, that said, I don't think I've read of anyone using it here on the forum, and I'm thinking you would rather have some replies on the general topic even if not from Seacast veterans.

[anchorout]

The latest on my NEW purchase: I don't see the SEACAST as being necessary. Yes, the saturation seems to be in the top 8 inches of the stbd transom. As described on this forum, the black transom cap had separated from the transom about an inch crack, just enough to let water in. The top of the transom was not sealed. Water had penetrated the grey board and turned a 6 inch section into mud. Surprisingly, the core looked like new balsa, but was completely saturated. I have removed core down to 6 inches and am still finding wet wood.

Someone please tell me again how balsa, still bonded to the glass on both end grain sides, won't absorb water into the grain.

Will injecting alcohol into the core speed the drying process, or is that an old wive's tale as well?

As for tilting the motor up and sitting on the foot to test the integrity of the transom, I'll give it a try, but you are scaring me to death.

My next move will be to remove the motor and check that area as well.

Thank you all for the quick replies and I will keep you posted

[thataway]

Looks like we have two related threads--no easy way to delete one and combine. I have offered a dehumidifier in the other thread, and sent a phone # since I will be in LA in a few days.

If there is just moisture, and the core of wood is not badly rotten or splintered, then the liquid epoxy injection method is probably going to be the best way to repair it, after drying out the transom. This is why I asked about the rest of the core and condition. I have tried the alcohol method of drying and was not happy with the end results. (Long story, but involved a Taiwan built boat with teak decks, and multiple deck leaks into the substrate.)

The drying process is not easy--it involves both heat and dehumidification-drilling multiple holes in the transom.

The balsa is placed on a scrim, and the scrim bonds to the resin saturated mat which is the layer of lamination next to the balsa. Balsa is a HARDWOOD--seems paradoxical--but it is based on the cell structure. I am not a botanist. Basically the cells in balsa have very light walls, and are going to be more lighter because of the structure. However there are channels which allow passage of water between the cells. Cells are cut with the manufacture process of the blocks of Balsa. Remember that Kon Tiki which was made of balsa logs became water logged at the end of the trip. So some absorption of water does occur with time. The good thing is that you don't seem to have any rot.

In your boat, it sounds as if there were foam on the top, which has disintegrated, and then the balsa. Transoms of C Dory's were plywood, balsa, combination of balsa, plywood and foam or all foam....

Depending on how the drying was going, I might be tempted to remove the outer layer; take out all of the wood/foam and go with Coosa board, then put the transom back together. This will take the least time...

[Sunbeam]

[thataway]

Sunbeam,
If the structure of the balsa core is intact, infusion with thin epoxy resin would provide the strength needed for the sandwich effect which gives the effect. Even the wet core has the strength--the danger is rot, and delamination.

[Sunbeam]

[anchorout]

Once I moved the motor out of the way, and removed the cap, and took core samples throughout the core, I found that the wet wood was present at the top stbd area, from the bad cap joint, and near the port lower motor mount (new motor 6 mos ago) poorly installed at the marina. (personally, I would NEVER let a marina near any core area of my boat.)

I drilled vertical holes through the wet areas, ran small diameter tubing to the bottom of each hole, all attached to a small vacuum. I placed heat lamps on both sides of the transom. After two days the holes have enlarged, signifying dampness is being drawn from the wood and it is shrinking.

I have found only a small area of rot around the bolt hole. all other wood looks like new. I plan to dry out for a few weeks, saturate with penetrant epoxy, regular epoxy, then glass in the top of the transom.

Thanks for all the advise and personal experiences given. Wish me luck.

[thataway]

Sounds like a reasonable plan. Be sure and use the proper thined epoxy, and then after it has set up, do the proper drill out, under cut of the other areas where holes were in the epoxy.

I would still use a moisture meter on the transom to follow the trying process. I think in this case of the relitatiely in-expensive Ryobi meters would be adequate, since you have the motor off, and you are looking at relitative values.

[anchorout]

Where can I get the dampness meter you mentioned? I do need to check the rest of the transom, though core samples indicate all is well.

[Sunbeam]