Bilge water after hard rain

[Jim in TC]

After a hard rain I have noticed that I can get a few strokes from the bilge pump, probably just a few cups of water but still. This has happened both when in the water at a slip and grounded in the driveway, and so far as I can tell (only have had the Sun Cat a few months) this is the only time there is water in the bilge. I don't see water under any hatch or locker covers. Where is it getting through?

[Zephyros]

The first place to check is your mast to deck joint, if there is caulking there at all it dries out over time creating a gap for water to get in. I know on the latest Horizon's there is no caulk there and it is a source of a leak into the anchor locker.

The second place to check is your black rubber gunnel deck joint. If there are any gaps on the deck side water runs in there. I saw this on one Suncat I looked at for sale and you could see water streaks / stains running down the inside of the cabin. Look for those telltale signs in the cabin and storage lockers for the leak source.

[JTMeissner]

I have a similar problem.  After a complete refit, I was finding water in the bilge regularly, and the boat was on the trailer...  Better to have water entering from the top than the bottom.

Depending on the power of the storm, we have openings that rain finds it way through.  First, the gap between the hatch boards and the cabin slide.  For me, it's about a 1/2", but with a good rain from the right direction, right on in.  Now I tarp over the hatch. Then, as mentioned, any top mounted feature.  Mast is one (I discovered mine is leaking there due to drips with varnish).  When I replaced the mast step, I used butyl tape and rubber washers on all the screws, but still...  I think I get some leakage through the cabin slide wooden guides.  That wasn't redone with the last refit, so I can't remember if i sealed properly (I have a long roll of butyl tape that I need to just fix them with).  I found water entering the cabin via the chainplate connections.  A lot of water on the deck then flows along the edges to the chainplates where it can go overboard, run past, or seep through.  Finally, the vent up front was leaking, so I pulled all the hardware, cleaned, and re-sealed with butyl tape.  Regardless, it's not a perfect seal with the way the cowl fits into the deck mount - with enough rain, water can work it's way around.  Also, if heavy enough, the rain can just plain splash high enough to fall through the cowl opening. 

So, a little bit of water is to be expected.  After heavy rains and winds, I have seen inches of water in my bilge, so it can be significant. 

-Justin

[Jim in TC]

Having not noticed any staining at critical locations I looked more closely and still see no clear evidence of leakage where I can see inside (and that is most of the hull though not all). There is a screw-on deck plate in the back part of the cockpit, though, and I don't think that is factory. Since not *all* of the work done on this boat before I took over was first rate (I am here demonstrating my gift for understatement) that is the first place to watch, especially since some sail ties I stored in that spot seemed damp...and I will continue to monitor for drips in other likely/possible places.

[stapes]

My bilge water came from leaky portholes. FINALLY after 4 years we took them off, scraped away the old gunk, and re-bed them with 4200. Not a drop since.

[Jim in TC]

Bilge water problems seem to have abated since I reinstalled that little spin locker in the cockpit. Now after several hard rains there is not enough water in the bilge to prime the pump...but I continue to chase small leaks around the cockpit.

[Joseph]

A couple of years ago some streaks of rain water were noticed wetting the inner walls of the cabin. Initially I blamed leaking portholes, but it stopped after sealant was applied on deck around the horn-cleats located at the beam.

J.