PosessionSound26PC
New member
Another leak disclosed by the previous owner was at the forward hatch cover. He indicated that he had tried to trace the leak but hadn't had any luck. He had tried applying a caulk intended for RVs around the outside of the hatch cover base (at the fiberglass) but this did not help. Any time it rained, the cabin headliner carpet would get wet, then drip down onto the forward berth cushions. He had improvised a temporary solution by keeping the cushions covered with a large plastic bag with a well in the middle to collect the water, which he would dispose of after a rainy day.
I started poking around up top and didn't notice anything terribly obvious but some water did seem to pool at the upper edge of the hatch where the previous owner had applied the white sealant:
Still, it didn't look like the water could get high enough to make its way up to the rubber bulb seal before flowing around and down the sides of the hatch area. I kept looking and then decided that the bulb seal was permanently crushed, dry and cracked enough that maybe water was getting in that way when it rained hard enough. The hatch is made by Bomar but the part or serial number had long worn away - you can see the crushed seal in the upper part of the picture below:
Here's a better view of the seal which no longer had any ability to make a seal as it had been crushed for so long by the hatch:
One of the other hatches had a readable searial number and I forwarded that to Bomar in the hopes they could identify the correct seal. They did and quoted P/N P100-52 at $7/ft. I found it cheaper at Downwind Marine in San Diego
I ripped out the old seal, cleaned out the slot it sits in and put in the new seal, taking care to glue the ends together:
Unfortunately, as soon as it rained again, the hatch leaked just as badly as before. The bulb seal was not the problem. I looked closer at the water drops on the inside of the closed hatch and realized that they were on the cam handles (shown above). Water could not have gotten on those handles in that position from the bulb seal - it had to have come from the outside seal between the lens and the aluminum frame. I had ignored that seal because it looked reasonably fine to me!
But fine it was not. I gently pushed upward on the lens from inside the cabin and it easily slid upwards and out of the seal - completely failed. Water was wicking right between the seal and lens or frame. I applied blue tape on top of the seal as a quick test and sure enough, the leaking stopped. I didn't have time to fix it over the winter but I did some research on the type of sealant I would need to use - there are many opinions. Many swear by butyl tape which does not cure and remains gooey and sticky (also messy...). Others rely on proven structural glazing silicones like Dow 795 that is used heavily in bedding glass in aluminum frames for buildings. Silicones can be a problem if previously used however as they leave behind a residue which prevents anything from sticking to that surface ever again - I know this from the aerospace field I work in. I will have to find a good cleaner (and possibly a primer) before putting the Dow 795 to work on the three hatch covers.
I started poking around up top and didn't notice anything terribly obvious but some water did seem to pool at the upper edge of the hatch where the previous owner had applied the white sealant:
Still, it didn't look like the water could get high enough to make its way up to the rubber bulb seal before flowing around and down the sides of the hatch area. I kept looking and then decided that the bulb seal was permanently crushed, dry and cracked enough that maybe water was getting in that way when it rained hard enough. The hatch is made by Bomar but the part or serial number had long worn away - you can see the crushed seal in the upper part of the picture below:
Here's a better view of the seal which no longer had any ability to make a seal as it had been crushed for so long by the hatch:
One of the other hatches had a readable searial number and I forwarded that to Bomar in the hopes they could identify the correct seal. They did and quoted P/N P100-52 at $7/ft. I found it cheaper at Downwind Marine in San Diego
I ripped out the old seal, cleaned out the slot it sits in and put in the new seal, taking care to glue the ends together:
Unfortunately, as soon as it rained again, the hatch leaked just as badly as before. The bulb seal was not the problem. I looked closer at the water drops on the inside of the closed hatch and realized that they were on the cam handles (shown above). Water could not have gotten on those handles in that position from the bulb seal - it had to have come from the outside seal between the lens and the aluminum frame. I had ignored that seal because it looked reasonably fine to me!
But fine it was not. I gently pushed upward on the lens from inside the cabin and it easily slid upwards and out of the seal - completely failed. Water was wicking right between the seal and lens or frame. I applied blue tape on top of the seal as a quick test and sure enough, the leaking stopped. I didn't have time to fix it over the winter but I did some research on the type of sealant I would need to use - there are many opinions. Many swear by butyl tape which does not cure and remains gooey and sticky (also messy...). Others rely on proven structural glazing silicones like Dow 795 that is used heavily in bedding glass in aluminum frames for buildings. Silicones can be a problem if previously used however as they leave behind a residue which prevents anything from sticking to that surface ever again - I know this from the aerospace field I work in. I will have to find a good cleaner (and possibly a primer) before putting the Dow 795 to work on the three hatch covers.