Leaking Starcraft

[tomats]

Well' I'll have to get the pix up but the resto is done, only upgrades now.

I took it for a run on a nearby lake and was surprised to see so much water was in the bilge.

Its a 1980 Mariner CC 18 ft with 90hp Evinrude

I'd say I am getting about a gallon of water every 15 min. I can't tell if its only when running on plane, standing or both. When I was doing the resto I filled the hull up to the floor level with water and only had a few sweating rivets that I since g-flexed, but other than that no leaks. I inspected all the seams and it looked like the front bow seam plate may have some gaps so I filled those and ran a bead all the way down the outside hull seam.

I'll get it back on the water on Sat, but wanted to see if anyone has had similar problems, from searching it sounds like the rivets are the real issue. I also noticed on the two outside chines there are 1/4 inch drilled holes at the end of each chine near the stern. Wondering if they should be there or not. The chines are sealed along the seams.

Anyway, I am stumped!

Rob

 

[boatnut74]

Re: Leaking Starcraft

Have you checked the condition of the transom? If you have a rotten transom water can leak in through bolt or towing eyes. As for the holes in the strakes, yes they are supposed to be there. The holes are there to drain the water out of them so it doesn't freeze and crack the hull.

 

[Bob_VT]

Re: Leaking Starcraft

Check your motor mounting bolts. Water can get in fast and flow between the wood and aluminum at the transom.

 

[tomats]

Re: Leaking Starcraft

Ok, that makes sense I won't seal up those holes.

I just replaced the transom and went overboard with 5200 on all the motor bolt holes, so I don't think its coming from there, but I will re-check

 

[MichaelP]

Re: Leaking Starcraft

Most folks are using Gluvit or Seal It to seal rivits and seams. Sounds like you may need some.

 

[boatnut74]

Re: Leaking Starcraft

Do you happen to have a livewell? I know on my old Crestliner the drain hose for my livewell had a hole in it and water was pushing up it and leaking out.

 

[tomats]

Re: Leaking Starcraft

it did have the front seat live well with just an aerator, no plumbing, but I converted it to storage.

I think I'll start with the bottom transom bolts and then the transom heel bracket bolts with some glovit and 5200 and go from there

 

[Starman8]

Re: Leaking Starcraft

As for the holes in the strakes, yes they are supposed to be there. The holes are there to drain the water out of them so it doesn't freeze and crack the hull.

Would like to discuss this fact, and my comments are based on fixing a few Star hulls and direct conversation with a Starcraft design engineer.

There is no reason to drill a hole in a perfectly solid one-piece hull, yet Starcraft did it, and eventually corrected it on the newer models.

STRAKES, answer this question. How would water get into a strake if no drain hole to allow water in was present? Not from the topside. The deadrise allows gravity to flow water downhill to the keeline and out the bilge and/or drain plug.

A hole in the strake allows it to fill with water while the boat is in the water. That is a problem. Go check the aluminum gauge of the hull near your strakes versus the strake itself. The strake is much thicker, like cardboard versus a paper hull. When underway, the thinner hull flexes and water can be introduced thru the rivet channels that attach the strake.

KEELPLATE, older models have the drain hole, same concept. Starcraft admitted the flaw.

Keels in the 90's and early 2000's had an open end in the keel plate(strip). You launch the boat, the keelstrip fills with water, then pressure and flex creates leaks. Starcraft admitted the FLAW, and closed off the open aft end of the strip in current models.

Any hole in the bottom of your "bowl" is a breach.

There is a solution. Just think of closing off the breach in SOLID fashion from the outside. Also, if you have an opportunity to use Gluvit from the inside, concentrate on the rivet channels that attach the keel strip and strakes. Work fast so the Gluvit is the thinnest possible and heat the hull from underneath with a space heater, even on a warm day and let gravity help.

If a Strake wasn't hollow, no water could get introduced into it!

 

[jasoutside]

Re: Leaking Starcraft

Starman - I believe what Boatnut was referring to is actually the keel (or keel plate), though I could be wrong on that.

As you know, those are hollow and unsealed on these boats so in order to drain properly they need a drainage hole. Both my Islander and Jet Star had only a single hole at the bow side. I actually added a stern side hole on both boats...

...as it really didn't make sense to have only one on the bow side.

Looking back at the original posters comments I hope we aren't getting too far off track here. How's it going tomats?

 

[MichaelP]

Re: Leaking Starcraft

Ha...I did the same as you Jason, great minds..... Just didn't make sense to have one in the front only. Figured they were put in backward near beer:30 on a friday.:facepalm:

 

[Starman8]

Re: Leaking Starcraft

jas,

visualize the flanges and hull compressed together by the rivet

hole in flange, hole in hull

rivet head outside the flange/boat, rivet fill in the two holes(channel), and adherence inside the hull

now imagine no drain holes, no water in strake or keelstrip

now imagine the hollow strake or keelstrip filled with water(constant when launched)

Is that water now past the first line of defense(rivet head outside the boat) and able to creep/seep into the fill channel?

Imagine the water under pressure!

Isn't a moving boat possibly displacing more water than a boat at rest?

Starcraft told me that the old designs are flawed because as the hollow chambers filled with water, and upon movement/running, the thinner hull will flex but the spines, or the thicker gauged strakes and keel plate will NOT.

This allows water under pressure to enter the hull thru the rivet channels made when the attachments were added. Starcraft said this, I didn't make it up, so...................

The poster asked for possible breaches/water leaks. I presented a know way of it.

What would I do first? I would put some tape on every drain hole, fill the hull with colored water as high as the strakes, below plywood and watch.

Even under no movement/pressure, wait to see for leaks. If none present, take the tape off. If colored water comes out of drain holes, that would be a start.

On my 2000 I sold, filling and closing off the open end of the keelstrip made the boat bone dry, even after 3-5 Lake Erie pounders, and on my current 79SS, did the same thing with the keel drain and on the strakes also. By the way, my 2000 strakes did NOT have drain holes.

 

[jasoutside]

Re: Leaking Starcraft

tomats, good info...

I would put some tape on every drain hole, fill the hull with colored water as high as the strakes, below plywood and watch.

Even under no movement/pressure, wait to see for leaks. If none present, take the tape off. If colored water comes out of drain holes, that would be a start.

 

[MichaelP]

Re: Leaking Starcraft

Isn't that seam sealed with a membrane like all the others? If so wouldn't the seal be the same on inside and out of the strake?
I'f mine were still inverted I'd try your test tonight. I suppose I could plow marine tex in the hole and cover it with tape till it sets up.

 

[Starman8]

Re: Leaking Starcraft

Isn't that seam sealed with a membrane like all the others? If so wouldn't the seal be the same on inside and out of the strake?
I'f mine were still inverted I'd try your test tonight. I suppose I could plow marine tex in the hole and cover it with tape till it sets up.

Not sure what you mean?

membrane/gasket, whether it is there or not doesn't seal the channel of any holes made for rivet attachment, the rivets goes in a thru hole.

never seen a membrane on my hull between the strake flange and main hull

inside the boat, you see the business end of the rivets, no membrane, gasket?

on a keelplate, that may be what you mean, but, a hole is a hole

no reason to plug with TEX, just use Butyl tape waterproof

 

[Gun Dog]

Re: Leaking Starcraft

I'd say I am getting about a gallon of water every 15 min. I can't tell if its only when running on plane, standing or both. When I was doing the resto I filled the hull up to the floor level with water and only had a few sweating rivets that I since g-flexed, but other than that no leaks. I inspected all the seams and it looked like the front bow seam plate may have some gaps so I filled those and ran a bead all the way down the outside hull seam.

Rob

I'm having a similar problem. I'm in the process of tracking it down. With the exception of a few small pinholes and one or two lose rivets nothing seems to be real obvious. I took the paint off the bottom and removed the deck. I'm going to take it out to the river soon. A little risky with no flotation but I see no other way. Since I'm taking on more water under power I'm going to run it to see if it's a flex issue.

 

[tomats]

Re: Leaking Starcraft

Thanks all great discussion!

Well, I did slow down the leak quite a bit, from about 5 gallon per 15 min to about 5 gl/hr.I am noticing that more water seems to be coming in under power but that might just be a result of the boat tilting getting on plane.

I sealed almost everything I could find that looked iffy. The biggest seemed to be the bow keel plate as it rose to the bow light, there were a lot of visible gaps near the water line. I also sealed the outer edges where the gunwale meets the hull as well as the stern motor bolts. All using G-Flex. I plan on sealing up all the rivets as added insurance.

As a recap I did fill the hull with water when I had the floor out and only had one rivet sweating that I repaired, so that was my decision not to gluvit the whole inside of the hull, which I now regret. What I think is actually happening is that on plane the force of the water can actually get thrusted in to any loose rivets that appeared fine when I filled the hull, secondly I do believe the strake holes could also be forcing water into the strakes and those seams could be leaking, and again not noticeable when I filled it. My plan is to plug the strake holes up with rubber grommets to see if that makes any difference.

I wish I could be more systematic to narrow down the cause for a solution, but I think the message is clear, when the floor is out, seal everything because its an old aluminum riveted boat!

 

[jasoutside]

Re: Leaking Starcraft

the message is clear, when the floor is out, seal everything because its an old aluminum riveted boat!

Perfect logic there!

Cheers

 

[tomats]

Re: Leaking Starcraft

Thinking more on the strake holes.. you can tell me if this faulty logic but..

since the holes are on the bottom of the strakes, wouldn't air have to escape for them to fill with water? So if you have good sealed seams then they shouldn't fill with water, however, if the seams are bad, air would escape, they would fill with water, and subsequently leak into the hull.Though once on plane there would be a vacuum..:facepalm:

 

[oops!]

Re: Leaking Starcraft

TO THE OP....... please dis reguard this statment and im sorry for your troubles....our guys will get the leaks out of your boat.

to the fourm guys......another leaking tinny? this would not have happened if it was a glass boat that said sea ray on the side.........

 

[jasoutside]

Re: Leaking Starcraft

To tomats - Those strakes/keel plate are not water tight and not really meant to be. I'd leave them alone. To totally seal up that boat you pretty much need to rebuck (or replace) loose rivets and seal everything up from the inside with Gluvit (or CoatIt, or G-Flex...).

If that doesn't work some guys have gone to running Gluvit on the outside of the hull. Course you need to get it to look good and paint over it to protect it.

You could also flip the boat and G-Flex each of the rivets. Might take you a while but it would prolly work.




To oops! - Take off your respirator, I can't understand a word your saying