Transom replacement on 1987 Wellcraft center console

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Old 07-10-20, 08:37 AM
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Transom replacement on 1987 Wellcraft center console

Iím replacing the transom on a 1987 Wellcraft 18 foot and I was able to remove the old without cutting the outer fiberglass on both sides. I have the new one cut but Iím looking for a way to glue the new transom to the existing fiberglass. Any suggestions on doing this right?
 
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Old 07-10-20, 08:54 AM
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Welcome to the forums.

I moved you to your own thread.

I'm thinking you're going to need fiberglass resin, hardner and possibly fiberglass cloth.
Is it possible to post a picture or two of what you are working on ?
How-to-insert-pictures.
 
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Old 07-10-20, 09:38 AM
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NO, it is not a simple glue your new piece in place. You need to fiberglass. Transom repair or replacement is a pretty important and critical structural repair. You need to watch some videos and do some learning about proper fiberglass work before attempting and don't try to get smart and cut corners.

If you've never worked with fiberglass be very mindful of the temperature and sun when working. Also beware of your pot of mixed resin and mind your hardener amount if using polyester. I usually use West System expoxies and you can get different "speed" hardeners to give you more working time in hot conditions.

And, if you are working and feel your pot of resin getting warm or jelling. Just stop and set that pot aside and mix a new batch.
 
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Old 07-10-20, 04:37 PM
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Thank you for the reply.
Itís raining here today but Iíll post pics as soon as it clears up.
I have checked out YouTube and Iím definitely not looking to cut any corners on this project thus, posting here for suggestions and ideas.
So far, two 3/4 marine plywood has glued and I was thinking of rapping the transom with new fiberglass and then somehow attach it to the existing fiberglass. This is whatís throwing me off because all the videos I watched have one side of the fiberglass cut out with old transom. I have inner and outer fiberglass in place.
 
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Old 07-11-20, 04:31 AM
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So you dug the old plywood out between the inner and outer fiberglass layers? I really think at least one if not both sides of fiberglass should go. If you have both sides of fiberglass remaining there is no way you can clean and prep the narrow slot to properly bond replacement wood.
 
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Old 07-11-20, 05:19 AM
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Outside transom


Inside transom

 

Last edited by PJmax; 07-11-20 at 09:50 AM. Reason: reoriented/enlarged/enhanced pics
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Old 07-11-20, 05:22 AM
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Hopefully this gives you a better idea of what Iím facing but let me know if you want to see any others.
 
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Old 07-11-20, 09:39 AM
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So, it does look like you are trying to slide new wood down between the two sides of old fiberglass.

The best way would be to cut off one side of the fiberglass, either the inner or outer. Then you have clear access to properly clean the other side. Then you at least have a chance of getting a good bond. I'd remove the outer since it's a simple flat piece where the inner gets into your bait wells/storage. You can use multiple screws from the inside into your new wood to help pull everything together well while the epoxy cures. Then you can do a traditional fiberglass job on the outside where you have easy access.

The next best way might be to try to drop the wood in like your picture. Do your best to get the inside of pocket clean. At the very bottom of the pocket drill a series of holes. These will be vents to let air and excess epoxy out so you can insert the wood. Drop the wood in place and drill a series of holes all the way through everything and get stainless steel flat head or carriage bolts, washers & nuts for each hole (don't put bolts where it will interfere with the engine mounting). Pull the wood out and clean everything. Get some helpers to hold the wood while you coat all sides liberally with resin and get it in the bolt holes. Try to coat the inside of both sides of fiberglass with resin. Then push the wood into place. You should get excess resin squirting out the bottom vent holes when you get the wood in position. Then insert your bolts from the outside ( you want the smooth flat heads on the outside where they are visible) so the nuts are on the inside of the boat and tighten them to hold everything together while the resin cures. The bolt will be left in place so make sure you resin them good to prevent leaks.

With the last method you are totally screwed if the resin kicks before you are done with everything (if it does start to kick you may want to pull the wood out while you still can). So, get a quality, predictable resin and do a test batch to verify your pot/working time before it starts to jell. Slower is better. This is where the higher quality resins are better. They are used for larger projects so they have the slow cure down to a science. Cheap polyester resin with drops of hardener can be quite hard to dial down to a slow cure while still getting a complete cure eventually. If you want to buy yourself even more pot time refrigerate the resin and hardener. Then float your pot of resin in a bucket of ice water to keep it cold which will slow the curing. And don't try to cheat and do less mixing. For a job like this you'll probably need a drill with a mixing paddle to do a thorough job.
 
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Old 07-11-20, 09:56 AM
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Some good advice from Dane.

Does that wood slide in easily ?
Like mentioned.... if the resin starts to set and the wood is not in place... it's game over.
Common sense would tell you to remove the inside fiberglass but it appears there won't be enough access to the ends which means removing the outside may be best.
 
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Old 07-11-20, 11:20 AM
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You guys are great! This does give me a boost of confidence, Thank you.
I pulled the wood out today and believe it or not, the inner fiberglass is white clean. Iím going to wash it a few times with acetone before I attempt the resin. I havenít bought any materials yet so let me know if you have any suggestions on resin that will take longer to dry. The temperature here is in the 80s so will use ice around the container that I mix it in and cool it down before I start.
 
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Old 07-12-20, 04:39 AM
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How can I treat the holes that I make under the transom? Will I have to fiberglass them or will the resin fill them in?
 
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Old 07-12-20, 05:09 AM
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I like West System epoxies and would use 206 or even 209 hardener. Notice that they list 100g for the pot size which is pretty small and the instructions will even caution you about mixing large batches in one container. When the resin and hardener touch it starts a chemical reaction that produces heat. The hotter it gets the faster the reaction occurs. When spread out in a thin layer on your boat the resin can cool and the hardening time is very predictable. In the pot the resin can't cool very well so it is dangerously easy in summer to get a "run away" reaction in the pot. Even when under control you can easily have a 20į temp rise if mixing a large batch.

Keeping the temperature of your pot of resin under control is critical. Too cool is OK as it will quickly warm back up when you spread it on the boat. An easy way to keep the temp down is to make smaller batches. For that you might need a helper doing nothing but mixing small batches for you to spread. You can also refrigerate the resins so they start out cool. You can keep your pot in a bucket of ice water while you mix & work. And of course work in the shade.

Below is the hardening chart for West System epoxy resin listing the working and cure time depending on temperature. It's important to note that the timer starts the instant the two components touch so your mixing time cuts into your pot & working time.



If you go with something like West System it's a good idea to also buy the metering pumps. They are sized to make measuring out the resin easy. Or, if you have a good digital scale you can weigh out the appropriate ratio of resin and hardener.

---
If you want to save some money you can use polyester resin which is probably what your boat was built with. It can work just as well as the more expensive epoxy resin. I would mix a practice batch of resin so you can work out the number of drops of hardener to use. You will need to accurately count the drops. Do NOT go "squirt" with the hardener.
 
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Old 07-12-20, 08:09 AM
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Sounds like West system may be worth the extra cost if they simplify the mixing with the pumps. Most YouTube videos use West system so hopefully itís within reach and itís worth it. I Can have my son mixing while I apply. Iím thinking I can use a thin roller to get into the cavity walls but this will take time. In addition, do you think I should apply the resin to the wood also?
Iím thinking this will make up for anything I may miss while rolling it on the fiberglass.
the one thing thatís scaring me is making the holes at the bottom like you suggested, not sure how to close them up.
 
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Old 07-12-20, 10:18 AM
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You close them back using the resin you are using for repair.
If the resin runs out the holes..... you'll just need to cut it off and sand once dried.
 
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Old 07-12-20, 01:48 PM
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I would coat the board. It will help insure it is sealed against water and with resin on the board and inside the pocket you'll have a better chance of avoiding dry spots or areas that don't bond.

If you've done it right filling the drain/vent holes at the bottom won't be a problem. Be ready for resin to be oozing and dripping out of the vent holes. You can cover the area around the holes with painters tape and make sure you have something to catch the runoff. Because of the resin's slow cure rate it will continue to slump & drip for a while. Don't be surprised if you wiped off a hole and have it nice and clean looking only to come back an hour later and see resin oozing out. Then after the resin is all cured you can come back and fill in any holes or voids with resin and micro balloons or a body putty to your liking.
 
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Old 07-13-20, 06:20 AM
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Finally no rain so today looking to clean up the entire boat with bleach and remove all the leaves that are in the boat. Iím also shopping for materials this week and will continue to cut and dry fit the transom.
 
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Old 07-13-20, 07:47 AM
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I pulled the wood out today and believe it or not, the inner fiberglass is white clean.
You know after reading this I got to wondering if the fiberglass was ever attached to the wood or how long the boat was used without knowing one way or the other. I'm thinking to myself that I wouldn't even try to glue the replacement wood in place and just get several stainless bolts to run completely through the transom at several locations above and below the water line and properly sealed. It seems that the strength and integrity of the transom would still remain. I don't see a down side to trying this though others will have differing opinions I'm sure.
 
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Old 07-15-20, 01:36 PM
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Well, dry fitting it is difficult to say the least. I stopped pushing it in because itís so tight that Iíll never get it back out. Iím thinking of drilling two holes one on each side so I can use a motor jack to get it out.
Any thoughts on the holes and should I be worried that Iíll compromise the strength of the transom?
 
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Old 07-15-20, 02:14 PM
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I really don't think you are going to compromise the transom with a few holes or bolts with fender washers since they will in effect make it a single unit. And if it fits that tight I again would not bother with trying to use any glue it could turn into a nightmare, I sure wouldn't try to glue if it were my boat and would not question it's integrity. Have you ever seen any of those old foldable boats? They used two layers of 3/8'' plywood with a rubber membrane in between with no glue and they worked just fine with outboards on them, I had one when I was a broke kid.
 
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Old 07-15-20, 02:59 PM
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Ok, Iím going to try it. If all fails, Iíll cutout the inner fiberglass. I do have a 150 hp for the boat and Iím trying to consider the 450 pounds that will be sitting on it.

thanks for the input.
 
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Old 07-15-20, 03:06 PM
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Understand the weight concern but that is shear weight and gluing it won't change that either way, just strategic placement of the through bolts should be sufficient. I would be most concerned with trailering but if you already use a transom saver you should be good to go.
 

Last edited by Ron53; 07-15-20 at 03:12 PM. Reason: spelling
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Old 07-15-20, 04:07 PM
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Proper bonding of the structure is important. It is especially important in high load areas like where the engine will be mounted. After all, it is why all the layers in a fiberglass boat are bonded together in the first place.

Take several sheets of fiberglass cloth and bolt them together. Yes, the pieces might be securely bolted together but the strength and stiffness of the structure is VERY different than if those same layers of cloth are bonded together by resin.

In this transom application any bolts are likely much stronger what they are holding together. Put a load on it and the bolt heads will pull through the fiberglass skins or wallow out the holes and leak. Unreinforced fiberglass simply cannot handle the point loading of doing all the work via bolts. More bolts would be better because the load is divided over more fasteners. It's why airplanes have so many closely spaced rivets. But best is if you could have the load spread smoothly throughout the structure. That is best done by gluing everything together into one structural mass.
 
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Old 07-17-20, 09:51 AM
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This is not working out the way I envisioned and it looks like I may have to cut either the outside or inner fiberglass. The pocket isnít the same width at the top and bottom, making it difficult to insert the plywood transom I have and I canít tell if itís cut correctly. So, looks like Iím starting over. Iím including a few more pics, let me know what you guys think


 
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Old 07-17-20, 10:28 AM
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Yea, transom repair can be a big job. For an outboard powered boat it's about the highest stressed part of the boat.

The inner skin will be a bugger to cut out and a lot more work to fiberglass back because you'll be into the storage boxes, floor and gunnels. The work will be in awkward and difficult locations but, it will be on the inside where imperfections will be harder to see and you could do a partial paint job. The difference between new and old will be visible unless you repaint the whole interior.

Removing the outer would be much easier. It's out in the open so you have easy access to work and it's a nice big flat thing so it's easy to glass. You'll have to feather the fiberglass around the sides of the boat for about 18" so you'll have to repaint the hull, or do a paint scheme where you only paint the transom and part way on the sides.
 
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Old 07-17-20, 12:03 PM
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Are you saying to rap the fiberglass around to the sides 18Ē from where I cut?
The YouTube videos I have watched leave about 2Ē on the back sides and bottom and I havenít seen anyone rap around to the sides with new fiberglass. The meet up to the cut and the 2Ē left of old fiberglass.
if you feel I would need to rap around to the sides, I think I would rather deal with the storage boxes and cut the inside.
 
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Old 07-17-20, 12:12 PM
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I still think you are going to have structure problems if you go cutting that glass, especially if you don't have much or any experience in laying glass maybe you could find someone to help with it. One thing I forgot to ask is did you get the old wood out in one piece?
 
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Old 07-17-20, 12:57 PM
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The old wood was removed by the other person that was redoing the transom. The wood you saw in the picture was new plywood that he gave me from when he was redoing it.
i have been trying to dry fit it but I canít get it in without getting it stuck so, I donít even know if itís a good fit. For this reason, Iím thinking of cutting glass so I can insure the new plywood fits in as close as possible to the sides and bottom
 
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Old 07-17-20, 02:29 PM
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It's not particularly difficult to repair fiberglass but you really should do some reading to learn how to do it properly. If you remove the outer skin you probably will have to extend your repair around to the sides and bottom of the hull. While you can get away with little/steep scarfing for non-structural repairs you should be closer to 20 to 1 or more for structural areas.. This means if the fiberglass you are repairing is 1" thick then you need to sand back at an angle 20" to provide enough surface area for bonding the new to the old.
 
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Old 07-17-20, 02:58 PM
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Your other and maybe the best overall option would be to convince the wife that it isn't repairable and you need to buy another boat.
 
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Old 07-17-20, 04:50 PM
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Thanks Dane, that does make sense. The outer and inner fiberglass are about 1/4 inch thick and if I have to rap it, so be it.
This is a learning project for me and Iím not giving up yet, I just have to figure out how to properly connect the transom to the rest of the boat.
 
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Old 07-17-20, 05:02 PM
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Just reading your initial suggestion on removing possibly both sides. This may be the only way to properly attach the transom so I believe Iíll start with cutting the outer fiberglass and work my way in.
thanks again
 
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Old 07-18-20, 04:05 AM
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I would NOT remove both sides. That could be done it's a whole mountain of work you might need to jig the sides of the boat to hold them in position. My vote is to remove the outer skin only.
 
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