Rub Rail / Hull Leak

[Kdubsc]

I have a new to me 2005 Mariah SX18 bowrider that I purchased last month. She is really clean for 15, but after having water in the bilge and not knowing her service history, I had all bellows replaced and the shift cable, trim sensors and impeller. I still had water in the bilge my last 2 outings, so purchased an inspection camera and sat at the ramp this evening looking for water. To my surprise, no water was trickling from the transom, or from the y-pipes while she idled in the lake.

What I did see was a drip or 2 from one of the blue drain plugs and a leak through the fiverglass right at the rub rail. I will probably try a new plug for the drain, but how would I best go about reparing the rub rail leak. It isn't a gusher, but a fairly steady stream that would no doubt account for my bilge water issue. I'll try to attach pics, but the leak is right at the back corner of the boat near the ladder. It appears either a poor job was done sealing or glassing where the top part of the boat joins the hull. I also saw extra screw holes that were void of screws but honestly dry under the rail.

In one pic, you can see the spot where water trickles in. Its at the center just above the tie down bolts. It is a dark, fiberglass colored spot unlike the white around it. I'll post the second pic which is where I suspect the water is getting in from outside. This is a "No Wood, No Rot" boat, so presumably nothing worry about there "I hope". What is my best course of action to fix this?

 

[Kdubsc]

Attached is the outside view with the rub rail pulled back. I believe the water is seeping in from the area to the right of the screw hole. Also note the white sealant below the rail area. Not sure if that was factory work or someone trying to stop the leak without taking the time to remove a few screws. Hopefully this is a "simple" fix.

 

[Kdubsc]

Well, used 4200 to seal it up a little after removing the stainless band and rubber underneath. I found numerous extra screw holes and sealed those, along with putting sealant in the holes before replacing screws. Honestly, I'm not sure how much water was getting in that way. I think it had more to do with the severe angle of the boat sitting on the trailer at thr ramp while I watched for leaks.

What I did fine was an o-ring missing from one of the blue plastic drain fittings. I reolaced that and stopped that leak. It was a drip when power off, and a little more steady at idle. I'm sure it peed water pretty good at cruising speeds.

I've committed almost all the cardinal boating sins in my 2 months of owenserhip. I've left the trim down and driven halfway up the ramp. I also left the plug out and noticed before I ever started her or unhooked the front strap. Telltale sign was the bilge pump shooting water. At least the float works. I got her out and let her drain before proceeding to put the plug in. Just for good measure, I pulled the drive to make sure I didn't get water it through the vent during that mishap. I didn't think to look at the water level at the time, but I dont believe it went up very far. No water in bellows, time to go boating!

 

[gm280]

Not sure how low your boat sits in the water, but most rub rails are high enough from the water line so not to have any issues. So if you are having water leak at the rub rail, you really need to find out why it is sitting that low in the water. JMHO

 

[dingbat]

I've owned two boats that had issues with water getting up under the rub rail and into the cabin/hull. Took me forever to figure it out but both hulls end up have the same issue.. a leaking hull/cap seam.

When on plane, water is pushed up and into the seam as the hull makes it way through wave action.

The PO ran a bead of silicon on the underside of the entire rub rail which worked until the sealant strayed peeling off in places. No leaks signs of water where the sealant was peeling, but water's capillary actions somehow managed to find it's way through the compromise seam.

Ended up removing the rub rail and the all the screws holding the cap and hull together. Filled the gap in the seam with 5200 and reinstalled all the screws. No more leaks after that

 

[Kdubsc]

Not sure how low your boat sits in the water, but most rub rails are high enough from the water line so not to have any issues. So if you are having water leak at the rub rail, you really need to find out why it is sitting that low in the water. JMHO

When I was watching for leaks, I had it backed in at the ramp with transom straps off. Still connected to the winch up front. It was also raining a little (the reason I was able to just sit at the ramp and not be in the way). I think part was the rain running down the rail but also sitting a little lower with me in the back looking around. My boat also seems to wash water up on the swim deck a little when stopping, so it sits a little low for sure.

I pulled the rail all the way around and sealed up any holes. There was also a pretty big gap in places between the hull and deck. Also resealed around ladder screws and the transom strap eyes. I suspect those might have been letting some water in, as they're submerged. Either way, didn't see any leaks from those areas the next time I was in the water.