please help transom leak

[marlin92]

hi and thank you for reading.
ok this it what I have:
1992 28 marlin twin yamaha f225. owned the boat for about 1 year.

well this is what my problem is:
3 months ago i noticed water getting into my bildge (only while I was moving). so after trying alot of things and not finding where its comming from. :hmm A freind of mine and my self went to sea test the boat with all hatches removed to inspect. well we found the leak. we did not even need to get it off the trailer.
how we found the leak. we backed the trailer into the water untill the boat was at a angel where it is when almost on a plane. I looked in the bildge. water was poring in from the transom :jaw (ok a little over the top but still) from many areas. the main area is where the motors are mounted.
What I think the cause is: where the motors are mounted there is a, whats seems to be a fiberglass cap over the transom. this cap has pulled away from the transom and created spots for water to enter. almost big enugh to put my finger in. also I took off the rub rail and where the cap and hull meet it seams the sealant has failed.
whats my fix? :huh
pull both motors, remove fiber glass cap, clean, place new aluminum cap, re-seal and remount motors and re-seal cap under rub rail.
Or
clean it up, remove old sealant and 5200 the heck out of it?

any words of wisdom would be great. thank you.

 

[VeroWing]

Some pics of separated transom cap would help a lot. Why would water be at top cap of transom when boat is in water? Seems it would only let water in when backing boat up. Are you certain thats where water is coming in? Check outboard bolt holes. Water can get in through seam on transom top, but it is usually not from water boat is floating in, more from rain and wash water seeping in. When your boat is under way and moving forward, water should be well below transom top. Possible it will splash up some on sudden stops.

Some model Grady's have brass tubes going through transom for cockpit drains that can get old and leak water into bilge. Have you checked those? Any other penetrations into transom or hull bottom are possible leak locations also and should be checked. Rub rail is possibility for some water entering, but unless you're consistently running hard through rough stuff, most water isn't hitting up there too much. You can pull it and reseal joint though.

 

[Fishtales]

need pics...
If I understand you right, it may be time to pull the motors and check the transom completely. At a minimum you need to address that water entry, likely new glass and sealing up fully. If this just started, you want to address it before it turns into a big problem.

 

[onoahimahi]

I had what sounds like the same gap with that fiberglass piece at the top of the transom and posted some photos here:

viewtopic.php?f=2&t=20095

I also just bought the boat this year and ended up trying to seal everything with 4200 including under the rub rail. Don't use 5200 or you will never get it apart when the time comes. My wood core is solid at the moment - the transom was rebuilt (for $5K) in 2006 when the E-TECs when on. The original transom only lasted 12 years.

Good luck,
-Scott

 

[VeroWing]

I had what sounds like the same gap with that fiberglass piece at the top of the transom and posted some photos here:

viewtopic.php?f=2&t=20095

I also just bought the boat this year and ended up trying to seal everything with 4200 including under the rub rail. Don't use 5200 or you will never get it apart when the time comes. My wood core is solid at the moment - the transom was rebuilt (for $5K) in 2006 when the E-TECs when on. The original transom only lasted 12 years.

Good luck,
-Scott

Scott, does that cap also wrap around the outside edge of the transom, or does it end under the outer edge aluminum molding? I'm not understanding how that open seam on the bottom of cap in splash area would allow water to get in bilge. Otherwise, the water would have to splash up between cap and transom, then up and over transom top to seam of hull and liner, then under aluminum molding to get down into bilge area. That may happen on launch and retrieval if transom top temporarily is dunked or water shoved over it, but there is no way water should be steadily entering bilge from there when boat is sitting or running in water, unless transom is dangerously close to water. I may be missing something though.

 

[onoahimahi]

I had what sounds like the same gap with that fiberglass piece at the top of the transom and posted some photos here:

viewtopic.php?f=2&t=20095

I also just bought the boat this year and ended up trying to seal everything with 4200 including under the rub rail. Don't use 5200 or you will never get it apart when the time comes. My wood core is solid at the moment - the transom was rebuilt (for $5K) in 2006 when the E-TECs when on. The original transom only lasted 12 years.

Good luck,
-Scott

Scott, does that cap also wrap around the outside edge of the transom, or does it end under the outer edge aluminum molding? I'm not understanding how that open seam on the bottom of cap in splash area would allow water to get in bilge.

VeroWing - the OP is getting water in his bilge, not me. I was showing him a picture of the gap I had which I think is the same gap he was describing. When on land before I launched, I discovered I was getting rain water in my transom from open gaps under the rub rail (I think) which I sealed up at the same time I sealed this gap with 4200. I sort of drained the water out of my transom by remove a transducer screw that penetrates the glass. The photo below shows the piece apparently wraps around and fits under the aluminum molding piece. The previous owner cut the molding to do some patch work and there is new gelcoat color on the fiberglass piece. The broker had some glass work done before I bought it.

To the OP - could it be the brass tubes? When the transom swells and expands, those things pull through sometimes. You should probably check or have someone check your whole transom - if you have any screws that penetrate the glass, try removing them and probing with an ice pick.