Rainwater leak under cockpit deck

[Alan K]

I have a Hunter 380 and the arrangement for getting the cable bundle from the cockpit into the vessel is identical. My dealer had to add cables for the rotary AutoPilot drive in the steering pedestal to that bundle along with the Rudder Position cable, so this is not how it was supplied from the factory. The cable bundle goes through a huge blob of RTV or clear Silicone Sealant where it passes through through the deck. All the wires are sealed by the blob. Leak free for 20+ years. A lot of water goes through there when I hose out the cockpit.

I'd clean out the caulk (yum) and seal it all up with RTV.

 

[matts997]

Several good ideas here...thanks everyone. I’m always impressed with the thoughtful comments that are generated on this forum.

I was hoping to avoid this, but I’m going to have to view the leak “in action” by running a hose onto the cockpit floor and then going below behind the aft bulkhead and between the holding and fuel tanks to view the leak from that side of things. I’m leaving on a 2-week trip this Sunday, so that will have to wait until I get back. But before I go, I’m going to fashion a temporary“tent” over the wire/cable bundle to see what--if anything--that does to prevent or lessen the amount of pooled water behind the engine.

I’ll let everyone know how this story ends--assuming it does!

Matt

 

[matts997]

My dealer had to add cables for the rotary AutoPilot drive in the steering pedestal to that bundle along with the Rudder Position cable, so this is not how it was supplied from the factory.

Just saw this...interesting. Now that I think about it, the leak may well have developed after I had my autopilot installed 3-4 yrs ago by a marine electrician who also added a wire to the bundle. Maybe I maligned the Hunter designers unfairly!

 

[LloydB]

Having successfully built a couple hobby fish tanks in another life it was surprising to find that silicone calking does not always provide a waterproof seal (from posters on this site). Was even more surprised when troubleshooting an electrical problem at a J box to find water coming out of one of the multicable bundles due to capillary action(different facilities more than once).fyi

 

[matts997]

I finally got around to removing the old caulk around these wires. I found 3 different caulking materials that were used previously and no one had apparently removed older caulking before applying the new. The last layer was applied by the electrician who installed my autopilot (the blue wire) and I believe it was he who drilled the 2nd hole---the smaller one on top. After that the leaking started.

Wondering if anyone would alter their recommendation, after seeing the holes w/ the old caulk removed? I don’t necessarily need a “forever fix”....just need the best caulking or epoxy possible, something that would do the job for 2-3 seasons before needing to be removed & re-done. It was surprisingly easy to remove the old caulking, using a product called Re-Mov Silicone and Adhesive Remover.

Matt

 

[Scott T-Bird]

Wow, you really do have a mess of cables! I am first thinking that it would be so much better if the cables passed through the deck under the pedestal where they are protected from water, but I'm guessing that when they are routed to the back they need go through finished space under the cockpit, so you don't want an exposed bundle of cables in your quarter berth for obvious aesthetic reasons. Perhaps there is a way to route it differently where they won't be in view????

My next thought is that I would try to first eliminate any cables that aren't necessary. You never know how many cables are added and abandoned in these routes over the years. I know on my boat I was able to get rid of several cables that were passing through in an unsightly bundle! And no, there is no way to keep water out permanently when water is traveling downward along those bundles. The silicone blob does work but is really undesirable for other reasons!

It looks like you could make a much neater bundle (or pair of bundles) with holes (or a hole) that are higher up that little wall. The upward passage of cables would eliminate that drip that you have going inside the boat. Instead, the flow would be backwards. I know, I know, who wants more holes! You would then need to fill or cover those existing holes ... but honestly, that looks like a butcher's job to me. I would definitely use those clam fittings for good measure. It may not be the easiest job, but I think you need to disconnect and fish all those cables out of there to start, and then do your repairs, prep and re-install (hopefully with fewer cables).

 

[jssailem]

looks like a butcher's job to me.

Yes. Quick and dirty. Slap some caulk on it. It’s all good. Lets go sailing. Any beer left?

 

[Scott T-Bird]

The cable bundle goes through a huge blob of RTV or clear Silicone Sealant where it passes through through the deck. All the wires are sealed by the blob. Leak free for 20+ years.

I've done that with success as well, but I'm not comfortable with it. It more or less makes those cables permanently installed and if you want to change anything, then you have a real mess to deal with. I was always frustrated about water leaking through the mast base on my Starwind, and finally resorted to the silicone blob. It stopped the leaking, for sure, but my cables for mast antennae, wind instrument and various electrical cables were locked in place. I sold the boat that way and apologized to the new owner for it!

Then, I found that my new boat was also commissioned that way ... a blob of silicone at the mast base. Catalina wrote a letter to the previous owner objecting that it should never have been done.

 

[JamesG161]

This is the reason why..

Water from Cockpit flows when rains or big waves.

Seal it with this.

Sashco 13013-2 13013 5oz Sealants Clear Lexel Adhesive Caulk - Walmart.com



Adhesive Sealant with great freeze/thaw properties.
Polyurethane.

It seals everything on my boat.

Jim...

PS: Silicone sealants

 

[matts997]

Scott--all of that is covered over by a removable section of cockpit floor. There’s only ~ a 1/4” between the lower hole and the “floor" of the starboard cockpit drain channel. (the close-up images distort the perspective....the “wall” there is only ~ 4” high). But a single hole could be drilled higher up, there is room for that. The problem is getting myself back to the connection points for some of these wires. I can’t shoehorn myself back far enough to reach the shore power connection (and I’m skinny, 6’, 160 lbs)...it’s right behind the fuel tank, with little clearance. The only person I know who could fit back there is my wife--and that will never, ever happen!

 

[matts997]

Jim--right on..the water flows beneath the wires and seeps into the bottom of the largest hole. So far only rainwater. I”ll check out your suggestion, thanks.

 

[jssailem]

Matts. As I perceive it you are faced with a dual problem. You have several wires that each allow water to seep along their surface to the hole, and you have a couple of holes that have space from the wire bundle to the edge of the holes to plug.

As a temporary fix you may find "Self-amalgamating tape" as an aide in filling some of the space either around the individual wires and the bundle. This may give you enough filler to get the caulk to work for a period of time.

https://en.wikipedia.org/wiki/Self-amalgamating_tape

 

[matts997]

Fortunately I think water seeping along the top of the wires is relatively minor, as the removable cockpit flooring has a lip on it that guides water falling on top of it into the drain channel--which then flows by and through the hole.

James--good idea about the self-amalgamating tape..I know I need something in there to provide a base or foundation for the caulk. I have access to the “back” of the hole, so maybe applying the tape to both sides will help.

 

[Siamese]

I had a similar situation on my old Catalina 28. Similar pedestal and cover over the steering gear setup. The Catalina also suffered from a poorly engineered joint between the pedestal and deck where water could get in and penetrate the core.

There are two things that I'd want to know about the problem you're having.
1. Is your core involved? If that vertical section, and the immediate surrounding area doesn't involve the core, then that would greatly lessen the severity of damage done by the water intrusion.

2. Where is the water going? On my Catalina, it dripped directly onto the aft berth cushion. Not good.

So, if you don't have a core issue, and if you're LUCKY, the water is finding it's way to the bilge without doing any harm, then you can avoid making a major project out of it. Cuz that's a tricky situation you have there with the runoff from the drain channel cascading directly on the cable bundle. The water gets inside the bundle of wires and sneaks in that way. Ugh.

So, if the core is safe, and the water's going to the bilge, I'd go with 3M 4200 or it's equivalent. Practical Sailor gave high marks to Loctite's sealant as a 4200 replacement, and it costs a LOT less. I got mine at Home Depot. Hopefully, no one used silicone around that bundle, as the new, proper sealant isn't going to want to stick anywhere there was silicone. But you knew that.

It's been my experience that relying on sealant to seal tends to be ineffective. It works best where the penetration has been engineered to deal with the water intrusion, and the sealant just provides insurance. That penetration was engineered to be a train wreck, so as you suggested, you'll be renewing the glob occasionally.

 

[matts997]

Thanks for the very thoughtful response...fortunately there’s no core water intrusion and the water does eventually make its way to the bilge, by running under the floor of the aft sleeping quarters. But it collects & pools under the dripless seal and will only seep out to the bilge when the water level gets high enough to make its way through the drain hole behind the engine. So every so often I have to "mop up" the collected water there after rainy periods. Granted, on the scale of serious boat problems, this ranks near the bottom, but it has bugged me for a couple years.

So my plan is to raise the wires up as far as I can w/out drilling a new hole and then using some type of sealant/caulk inserted from both sides of the opening, w/ tape or other material to provide some packing around the wires. And see how that holds up over time.

Thanks for everyone’s input, appreciate it.

 

[Scott T-Bird]

So my plan is to raise the wires up as far as I can w/out drilling a new hole and then using some type of sealant/caulk inserted from both sides of the opening, w/ tape or other material to provide some packing around the wires. And see how that holds up over time.

Just wondering if you *know* the purpose of each one of those cables and wires. Even if you can't completely reach them on the back end, you might be able to at least eliminate any that may not be necessary as they pass through in a bundle.

 

[twalker H260]

Cable clams can handle several wires per clam. Most instructions indicate to leave a minimum of 1/8” (.0125) of rubber between wires.

Not sure how many wires you have but suspect you could handle all your wires in 2 clams. The image with 2 wires is from my boat, you can see there is plenty of room for some additional wires. 5 or more are easily doable in the larger clams.