Aft Cabin Water Intrusion on my 40.5

Don S/V ILLusion · Jan 24, 2011

Michael
If it is the same problem I had with a similar leak, the source was a crack in the hull/deck joint caulking at the transom (where the transom rub rail starts).
Also check the aft cleat bedding in the same area while you're at it. Hope it is as easy to fix as my experience.

Don Lucas · Jan 24, 2011

I've read of this leak from the stern hull/deck joint now a few times. It would just seem that this is a prime location for a leak as it is under water so much.

So the follow-up question would be; why not expoy and tape the inside joint in the stern as a matter of preventive maintance? Is there a down side of doing this?

Don S/V ILLusion · Jan 24, 2011

Don Lucas said:
I've read of this leak from the stern hull/deck joint now a few times. It would just seem that this is a prime location for a leak as it is under water so much.

So the follow-up question would be; why not expoy and tape the inside joint in the stern as a matter of preventive maintance? Is there a down side of doing this?

The location to which I referred is not below the waterline or near it but rather just aft of the stern cleat on deck. As such, the only water source is rain.
The stern joint itself is glassed in. Apparently, Hunter did what every other mfg does and glue and bolt the hull/deck joint from that point forward to the bow.

Not sure I explained it clearly enough and don't have any pics.

Don Lucas · Jan 25, 2011

Maybe it was me that didn't explain it correctly. Don't know about the 40.5 but the 410 and many boats in the same time frame and later the hull/deck joint goes down to the waterline. The swim platform is part of the deck, not the hull so the joint is at the waterline.

On my new 410 I can see from the waterstain that the very bottom is regularly just under water. Far as I know the inside of that joint is not glassed in. Just 5200 sealed and bolted.

Don S/V ILLusion · Jan 25, 2011

Don Lucas said:
Maybe it was me that didn't explain it correctly. Don't know about the 40.5 but the 410 and many boats in the same time frame and later the hull/deck joint goes down to the waterline. The swim platform is part of the deck, not the hull so the joint is at the waterline.

On my new 410 I can see from the waterstain that the very bottom is regularly just under water. Far as I know the inside of that joint is not glassed in. Just 5200 sealed and bolted.

On my 40.5, the joint near the waterline is glassed, both outside and inside. It is also well below the level at which Michael is leaking water.

Bill Roosa · Jan 25, 2011

Dito Don

Same problem, same solution.
my stern does not leak either but have never looked under the bumper to see how it is constructed. Only goes underwater when we get above 5 knots and the stern sets down.

John T1594 · Jan 25, 2011

Aft cabin leaks

I had a similar problem on my boat a H340 and I'll bet the design and construction of your boat is similar. Both my waste holding tank and fuel tanks sit on platforms behind the bulkhead that is behind the aft berth. The platforms continue forward under the bulkhead to form the bed platform for the aft berth. I had a leak along the coaming of the cockpit - mine was from the shore power inlet but there are lots of other potential sources. There was a breakdown in the caulking and rain water would drip onto the top of one of the tanks then down to the platform and then forward under my aft berth mattress. Keep looking and look up from where the water pools behing the bulkhead.

Rick D · Jan 25, 2011

Michael, My Leak Experience....

...was a little different. I found out it was the cockpit shower fixture leaking. I had it happen three times; only after I had been on the boat some time with the water pressurized. The darn thing kept loosening up over time. I finally fixed it by adding shut off valves under the aft head sink so that there is no pressure back there unless I want it. Good luck!

David Knauer · Jan 30, 2011

I have this same problem on my boat. The area that I suspect is the starboard tow-rail around the aft starboard cleat. I plan on removing the tow-rail for the first few feet and re-caulking the joint as well as re-bedding the cleat. In the original article Marco Garcia stated that the leak was in the starboard cockpit locker were the locker joins the inner-liner of the boat. Of course, it could have originated elsewhere higher up. However this is definitely a problem in the (around 93) 40.5's. Hope this helps.

timvg · Jan 30, 2011

Like many things in boats, leaks come and go without logic sometimes. We had the same problem a couple of years back. Fortunately, we have always had dri-dek under our mattress, as it's a great way to keep condensation from touching the mattress. But the side of our mattress got wet from touching the back wall. We added some additional dri-dek between the mattress and back wall, so now the mattress doesn't touch anything. So even if water were to enter under the back wall, we will not get a wet mattress. This solved the immediate problem, as we started to track down the leak.

We realized that some (fresh) water was getting into the aft hatch where the fuel tank resides. As long as the water is kept out of the aft cabin, all that happens is that any water getting into the aft hatch will find it's way into the bildge. So, I took some marine sillicone and sealed the edges and bottom of the aft wall from the inside. This of course didn't fix the leak, but temporilty keeps any water from entering the aft cabin. IT WORKED.

I haven't found out where the water enters the aft hatch when it rains, because like many things on a boat, it hasn't happened again. California had over 10 inches of rain in December and no leak. But my "temporary" fixes should keep water out if the leak decides to visit me again.

Brian R · Feb 5, 2011

Michael,
I agree with the other posts about potential leak areas. I would also suggest looking at the location that the cables under the steering deck penetrate the the stern locker (on my 40.5 it is near the shower hose). I found the chalk used around the cables insufficient to prevent water running down the cables and into the stern locker. From there the water would run across the locker floor, down the bulkhead and ultimately to the stern bunk. I resealed the cable penetration and the problem was solved. I hope this helps.
I will attempt to post a picture of the area I am talking about.
Best regards,

Rich Stidger · Feb 5, 2011

The classic h40.5 aft cabin leak

My '97 model leaked into the aft cabin right after delivery. My dealer looked at it and said "Yup, the classic 40.5 leak."

WHAT?!!

My dealer explained that he had seen that same leak on a number of 40.5's that he sold and that the cause was a poor deck to hull seal at the aluminum toe-rail.

According to him, the cause was due to a factory defect. It seems that where the factory needed to place the hull during production at the time of the hull-deck caulking, there was a factory roof support close to the port side near the aft cabin. When the worker ran the caulk down the edge, he had to stop and reposition himself on the other side of the roof support and then continue the caulking. The claim was that the caulk had a gap due to the stop and re-start. I realize that this may seem bizarre, but that is what I was told.

My dealer pulled off the port toe-rail, re-caulked, and I've not had the problem recur (it's been 13 years).

I don't know how far the toe-rail needed to be removed, but perhaps someone else can add this info.

This may not be the cause of your leak problem. YMMV.

Jlambert61@msn.com · Feb 14, 2011

Leak in aft cabin

I also had a leak in the aft cabin and I was able to find out where it was coming from. My leak was under the removable deck cover that you stand on when driving the boat. It turns out that they didn't seal the hole on the starboard side where all of the pedestal wiring goes into the boat. Once I sealed the hole I solved the problem.

Jack Lambert

Michael G said:
I have a 1993 40.5 and for the past few years I have had a problem with water leaking in from behind the aft cabin wall where the fuel and one water tank reside. The water seems to be coming in on the fuel tank side and seeps under the wall and soaks the cushions and the bed sheets. It has also soaked into the wall to the point that I will probably have to remove and replace the whole wall in the spring. I did see that Marco Garcia had written an article in the 40.5 owner’s modifications that will be helpful during the wall removal. I would love to find a fix that can be accomplished at a seam or origin of the leak on the outside of the boat so not to have to remove the wall right away.

Any Ideas ???? Would Appreciate any Help :cry: !!! Thanks

rpleblanc · Feb 22, 2011

+1 for Brian R.

Had fresh water leaks after a heavy rain or very aggressive wash, took a while to track down, as water travels!

Aft Cabin Water Intrusion on my 40.5

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