Please help me diagnose this leak.

[mattymuch]

Still trying to track down this leak. The boat is 31 years old and im sure the transom does have some rot, but i want to find where this water is coming in i have sealed all swim platform bolts trim tabs bolts and underwater lights with 5200 and the leak is still now different? There is silicone around the gimbal housing where it goes through the hull could it be coming in there? The blisters in the fiberglass where the water is coming in is high up, i did fill the bilge but the leak is to high on the transom for the water in the bilge to reach. I did find water dripping from a hole on the gimbal housing where the trim lines attach.

You can see the water ready to drip from the hole this is with the bilge filled and boat tipped up on the trailer. The other pictures are when the boat is in the water.

 

[Scott Danforth]

did you add the silicone around the gimbal housing or did you buy the boat like that. generally that is a band-aid fix to stop a leak from a rotten transom. there is a transom seal that seals against the transom.....until the transom gets soft and the bolts loose clamp force. then people try to seal up the leak by caulking around the gimbal housing.

dont fill your bilge with water while the boat is sitting on the trailer. this does 3 bad things. first, it overloads your trailer, next is gets water into places water shouldnt be, and lastly, if your starter gets full of water, it will be junk in short order.

proper way to find a leak is to dry out the bilge, then back boat into water, crawl into bilge and look for water coming in. you may need flashlights, mirrors or your cell phone camera to find them.

to check the transom, put the outdrive up, have someone stand on the outdrive and bounce up and down while you look at the gimbal to transom connection. if you see any movement, your transom is soft and needs replacement.

 

[mattymuch]

I put the silicone around the gimbal, that was probably 3 years ago, i didnt know what i know now about boats and i sealed it because i was taking on water then but it ended up being one of the bellows