water in bilge

I am getting 2 or 3 gal of water in my bilge when my MS 34 is exposed to a heavy rain. Could the leak be from the caulked seam which I guess is at the base of the fly bridge or could it be leaking some where other than the seam? Also what type of caulk should I use if that is the source of the leak ?

One of and perhaps the most common source of leakage is the rubrail. This is not unique to MS but it may be more frequent.
You can verify location by taking paper towels to inside of hull or dusting the inside of the hull with colored chalk used for carpenter chalk lines. The runs will be much more visible.
If you scan through my Bacchus website Projects section you will find more details about the repair.
Some others suggest simply cleaning the top of the rubrail where it joins the hull and recall this area. It will work for a while so I consider this a temporary fix.
Removing & repairing the rubrail is closer to a permanent fix.

I get some from lazarette hatch occasionally.

Thanks ! the rub rail seems a good point since I am getting small amounts of water in 2 or 3 areas which are not connected to a common drain source.

In my case most of the leaks were around mid ship and ran down / was noticeable on the "shelves" where the battys are. I also had some at the stern.

Another question for Bacchus. In order to properly seal the rub rail I would remove the metal outer strip and then the plastic rub rail part which is directly attached to the hull ? After those are removed where would I place the caulk ? I am guessing it would be the split that is held together with the short screw. Also do I need to caulk all the screws that attach the metal outer strip ? Thanks for your help.

keith c said:

Another question for Bacchus. In order to properly seal the rub rail I would remove the metal outer strip and then the plastic rub rail part which is directly attached to the hull ? After those are removed where would I place the caulk ? I am guessing it would be the split that is held together with the short screw. Also do I need to caulk all the screws that attach the metal outer strip ? Thanks for your help.

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After removing the metal trim and the PVC rail I made sure all the gaps in the hull / deck joint were filled. In several places the short screws had pulled through the fiberglass and I used short bolts & nuts. Having a grinder with cut off wheel is helpful as there is not much room for bolts.
I then layer a generous bead of caulk at the inside 90° corner of the deck flange. The PVC rail was then seated into that bead and screwed in place. My thinking is sealing the edge of the rail is batter than just a bead of caulk after rail is in place.
I also drilled a few holes in the bottom of the PVC rail so any water that did get in had a place to drain out instead of backing up into the hull to deck joint.?