Leaks on 1996 19' Starcraft

[biederboat]

Hi all,

First time posting in this particular forum, I've posted a few times in the engine section. I've restored two previous Starcraft boats, a 1966 16' and a 1972 21' Chieftain. The Cheiftain was converted from a cuddy cabin & i/o to an open bow and an outboard. I have done one heck of a lot of riveting and used some structural adhesives with good success.

My current boat, a 1996 19' Sportfisherman (or something like that, it's been painted over) has a leak problem that is driving me crazy. I have filled the boat with water a few times (which doesn't take much as the floor is poured-in foam) and I find only a few slow leaks. When afloat, the bilge pump cycles around 10% of the time, quite excessive! I cannot see any water coming in from the transom (can't see water running in there when looking into the bilge). The pump usually kick in when accelerating (like the water was sitting in the front).

I suspect that the water is coming is from a leak that won't "reverse flow" when filled with water on the inside and the boat on the trailer since the water can't reach that area easily with the foam in the floor. Short of tearing out the floor again (I replaced it with a composite floor, don't really want to tear it out) and pulling out the foam, I don't know how I'll find the true sources(s) of the leak(s).

Any suggestions on where or how to look for the leak? I've inspected a lot of the bottom and just can see any logical sources. Also, I see a lot of people using Gluv-it. I used that on my 16' years ago but it tended to crack. I've heard better things about Coat-it but I'm still hesitant to coat the bottom of this boat with a thick substance that might crack.

Thanks,
Biederboat

 

[fshngho]

Re: Leaks on 1996 19' Starcraft

I think Gluvit is the "go to" product that we all use. Did you cover the gluvit last time? It is not UV resistant so that may have been the problem. It needs to be painted if subject to sun. It is not supposed to crack, as you know. Is the Sportfisherman an IB? You may have leaks around the outdrive, but since I don't own one I can't help you much there. Good Luck

 

[jasoutside]

Re: Leaks on 1996 19' Starcraft

Holy smokes, sounds like you have some awesome projects happening there! We need to see photos of your work man!

As for your leaking I guess you only have two ways of fixing it. Seal up from the inside or seal up from the outside.

Going the outside route might be less work for you - prep, gluvit and paint maybe???

 

[tinkeringwackyone]

Re: Leaks on 1996 19' Starcraft

fishngho has definietly got an idea, if you have an i/o, you could have a leak around the outdrive area, or could have a leak from the cooling system itself, such as a rotted hose.

Good luck finding your trouble.

sail on.....tink

 

[ezmobee]

Re: Leaks on 1996 19' Starcraft

Got any livewells on that thing? The plumbing for those can certainly be a leak source.

 

[64osby]

Re: Leaks on 1996 19' Starcraft

biederboat

(I replaced it with a composite floor, don't really want to tear it out)

What composite did you use? I am looking for alternates to glassed wood floors.

 

[biederboat]

Re: Leaks on 1996 19' Starcraft

Hey guys, sorry it took a while for me to respond. Some forums just don't let me know when I receive replies either though my email address is in my profile and I select "instantaneous response" when I post. Go figure.

Anyway, here's some answers.

Present boat is an outboard and I'm 99% certain leaks are not coming from the transom. I can see most of the transom area from the inside and there just doesn't appear to be any water coming in anywhere. Also, I have backed the boat and trailer into the water at the boat launch (with the straps on) and I don't get water leaking into the bilge. At this piont, the transom is way into the water and only part of the hull is under water. Any water leaking in would collect immediately in the bilge (due to the angle of the boat) and none really collects.

When I had the Gluvit on my old boat, I'm pretty sure it was painted. This was an old hull (early 60's) and had a fair amount of flex. Interesting that everyone prefers Gluvit over Coat-it. Out here (in Oregon) on a local fishing forum, Gluvit gets regularly bashed and people are told to use Coat-it. I haven't used it myself but I did put some on a test panel and it appears to take flexing somewhat and adhered quite well. Anyone out there used Coat-it?

There used to be a livewell, the pickup fitting is now a wash-down pump intake. I check the fitting and hose recently.

The floor I installed is from Spaceagesynthetics. Good stuff, very light, won't ever rot but a bit hard to hold down. I suspect the hull is flexing more that it should. The outboard edges of the floor don't have good brackets to fasten the flooring to. If I were to do it over, I would likely lay the floor "crosswise" rather than lengthwise. There are basically three 2' x 8' sections starting at the transom going in parallel that end between the front and back sets of seats. Going crosswise would have stiffened the floor by laying solid sections all the way across left to right but would have made servicing the fuel tank more difficult. As is, I need to remove the splashwell bulkhead and then the section over the fuel tank but I would still have done it the other way.

If I get energetic I'll post some pics of my previous projects. On my first two projects, they both had "outside rivet row" hull disease (the hull cracked along the outside row of rivets just inside of the chine). I had flat plates laser cut from a design I made in a CAD system that essentially doubled the thickness of the hull (on the planing surface) on the sections between the chine and the hull stiffeners (going along most of the length of the hull). Had to first drill out all the existing rivets, and then rivet in the new plates. Worked great but was a fair amount of work. Both boats were stripped completely to a bare hull and flipped over. I riveted and my wife bucked.

Overall, I'm still looking for ideas on how to find that dang leak. I really don't want to apply Gluvit or Coat-it and find that's not the cause.

Thanks,
BB

 

[fshngho]

Re: Leaks on 1996 19' Starcraft

My last idea is one you will not like. Since you have poured in foam, water could be coming in around a rivet or seam when in the water but when you fill the inside a peice of foam could "flow" and block the area from leaking. Yeah, this would mean removing the floor & foam, sorry. The only other thing I am concerned about is the rigitity of the boat now after installing the floor, These old boats are meant to flex a bit and if you remove that as an option, would that increase the chances of cracks and/or loose rivets? Just a thought and I don't know the answer. Keep us up to date and good luck.

 

[64osby]

Re: Leaks on 1996 19' Starcraft

biederboat - This is just an idea, I might be crazy, but it might be worth it.
I know on engines they can dye the oil so you can find a leak.

Maybe there is some product, water based, water solvable, that you could brush on the seams and rivets. Maybe even thickened food coloring. Use three different colors blue, red and yellow- bow, center, stern. Float the whole boat and see if the water inside has a certain color, that might show what part of the boat the leak is coming from. If the bow was blue and that turns up inside, then do the bow in three colors, port, center and starboard.

If you get purple, orange or green you have leaks in two areas. If you get black its leaking all over.

If this works you still might have to pull the floor and foam out, but maybe just in one spot.

The Spaceagesynthetics web site looks interesting, How did you attached it? What kind of surface does it have? Cost?

Post some pics of your boat.

Good Luck

 

[biederboat]

Re: Leaks on 1996 19' Starcraft

Well I thought about that issue (the problem with trying to get the leak to show from inside the boat). That's a definite possibility. I'm intrigued about the dye, that might help. There's a couple of things I remembered and it's becoming complicated from having so many other issues and not having run the boat much recently (too much hunting!). This includes finding some leaks that I fixed that were definitely problems at one time but aren't anymore (like swim platform bolts, a couple of small leaky rivets up front, etc.). But the most interesting thing that, I'm not absolutely certain of but at least "pretty sure", is that it doesn't leak as much while on plane. You think this would point to a transom issue but, as I said in my original post, I backed the boat down w/ tie-downs still strapped on and NO water came into the bilge area. This tells me that it must be towards the front enough so, when that portion of the boat is out of the water under plane, it doesn't leak. I think I'll test this more thoroughly by staying at idle/trolling speeds for a 1/2 hour (w/ bilge on manual) and see how much water comes out when I turn bilge on and go underway (sends water back to bilge). Then I'll stay at planing speeds for a 1/2 hour with the bilge off and see if there is water in when I turn the bilge on. If there's not near as much water in the bilge from being on plane, I would have to think it would be the front bow area, agreed?

The space age is not cheap, around $200 per 4 x 8 sheet 1/2" thick. SUPER STRONG, very stiff and light though. You can carry that sheet around by grabbing it by the edge with one hand.I do think it's a "forever" floor but there are some issues. You're pointing to one, it doesn't really like a flexible floor. The best way to fasten it down is some adhesive (liquid nails) and then the super-long pop rivets (that "flower" on the blind side) over the floor covering. An ideal way would be to put riv-nuts in the support structure but that's more complicated. To get a true uniform thickness, you want "sanded both sides" which has a good semi-porous (but not water absorbent) surface that will take adhesive for a vinyl floor. I will try and post some pics but I didn't take many during the construction phase.

Oh, and thanks for the help everyone!

Biederboat

 

[fshngho]

Re: Leaks on 1996 19' Starcraft

Chances are very good that when the boat is on plane you won't get water in UNLESS the hole is faceing towards the front (flow) or the leak is above the waterline. I had a fiberglass boat that cracked sideways under the hull. It would have sank sitting still but I got it on plane and could see the leak was slower. I ran it untill I got to the beach and grounded it.