cracked gel coat (picture added)

[Addicted]

So while removing my cleanout tray, I ended up breaking the through hull fitting (underside of the swim deck facing down) on the right side that drains the water from the top of the tray. As I see it, I cannot install the new one without removing the jet assembly, as it sits out far enough to cover about half of the hole. Not just the jet assembly, but the plate that the jet assembly mounts to. Ok, not real happy about the design, but what can I do about it now....so I grab some tools and get under the boat to begin disassembly. What I found were fairly large cracks (between 1/2" and 1 1/2" long) in the gel coat at all 4 of the upper bolts (2 each side). This seems like a pretty big deal to me. Has anyone else seen this?

Also, anyone have any experience replacing that through hull fitting? I would really like to find a way to replace it without disassembling everything. I have removed the pump housing previously, and that is a piece of cake, but this appears to be the main seal for the back of the boat. I would like to not open that can of worms if at all possible. I have decided to hold off until I get more info on the cracks though. If these turn out to be a warranty issue, I do not want to remove anything back there, and have it come back to bite me. Plus if there is a repair needed, the entire assembly would be removed anyway, and the fitting will be easy at that point.

I will shoot some pictures tonight of the cracks. There are 5 or 6 that spider web out from each of the 4 top bolts.

Any thoughts?

 

[Bruce]

I believe that others have had cracks in the gel coat in this area. I look forward to the pictures so that we can better understand what you are seeing.

 

[Addicted]

I am wondering if these cracks in the gel coat, allow moisture to soak into the fiberglass, or if this is simply a cosmetic issue? It also concerns me that the crack are visible at all 4 upper bolts, and none on the lower.

I have come to the conclusion that the through hull fitting cannot be replaced without pulling the entire assembly.

 

[txav8r]

Yamaha will tell you that those are strictly cosmetic. Are you sure that that drain fitting can't be removed without moving the pump base?

 

[Addicted]

Yamaha will tell you that those are strictly cosmetic. Are you sure that that drain fitting can't be removed without moving the pump base?

Even with the bolt removed, the plate covers 1/3 of the hole. I have tried to install the OEM through hull, and there is no way. I purchased a shorter fitting, with a smaller diameter outside face, and still not even close to being able to install it. I am certainly open to any ideas, but as I see it, the pump base needs to be removed. The picture is somewhat misleading. The fitting in the picture is not the one to be replaced. It is actually the other side, and the pump base covers more of the fitting than what is shown in the pic above.

Do you consider the cracks cosmetic? Is it something that you would be concerned about?

 

[txav8r]

I know those cracks are concerning, they would be to any of us. I have found one around one of the notorious windshield screws too. Most boat manufacturers say they are cosmetic and won't cause a problem. I wonder if a fiberglass shop would tell you the same thing? @Glassman , may be able to shed some light on it. I can't imagine that any cracking, spider or otherwise, wouldn't pose at least some exposure of water to the fiberglass structure under the gelcoat. But if you have any warranty, I would consider running it by Yamaha if we determined that your substrate may be subjected to unwanted delamination. Several questions...do you keep the boat in the water full time? If not, and only trailer, I might be inclined regardless, to look at it less concerned. I say this for several reasons. First off, time to absorb is reduced and almost eliminated, and second, time to dry out if it did. I know none of this makes you feel any better about this, but I also suspect if everyone that owned a boat were to do a close inspection such as yours, there would be many with the same, if not more, issues like this. The fitting on the other hand...if the only way to get that fitting into the hole is to remove the pump mounting base...I think I would be considering gluing the broken fitting or whatever I could do to reduce the need to pull the pump and mounting plate. I think asking a repair shop would ultimately end in them thinking they would get the business, so the opinion is less valid...lol, in my opinion. I honestly think that it is merely cosmetic, but that doesn't help you with the drain fitting.

 

[brockhals]

So you've had the pumps off previously and I presume didn't notice any cracks before. From the pics it looks like spider cracks from over tightening the bolts.

 

[Addicted]

Thanks for the reply Mel. I do have a the 5yr YES, so as you suggested, I intend t at least have Yamaha take a look at it. I rented a slip at my local lake last summer to keep the boat on the water. Those 4 months were the only, that the boat has been in the water full time. I don't think I will do that again though, as I found it very hard to keep the boat clean and maintained in a way that made me happy. So, the boat will likely spend most of it's out of use life on the trailer from this point forward. Last night while looking at the through hull, I started to consider getting creative with the fitting as you said. I really do not want to break the factory seal back there, especially if there is any chance that the cracks could be a warranty issue. The thought of a MacGyver move for a through hull is a bit sketchy though.

@brockhals, I have removed the pump housing from the pump base, to remove a piece of wood jammed in the impellor, once. However, I have not removed the pump base. Over the weekend I removed the single bolt, just below the through hull fitting to see if it would allow enough clearance for the new fitting, but other than that, I have not touched those through bolts. Like you, I initially thought that they were over tightened during installation, but after realizing that the top four show cracking, and none of the bottom four do, I started to think that torque may have caused the issue. I am certain that these were not present when I removed the pump housing, but that was the first year I had the boat (2012). Admittedly, I have not inspected that area well enough since then, so I have no idea when they showed up.

My biggest concern with the cracks is the potential for water to break down the structure underneath. Mel may be right though, that the boat spending so many hours out of the water may reduce or eliminate that potential.

I appreciate the responses. Although I was hoping for 12 guys to chime in saying "don't worry about it, I have had cracks there for years" .

 

[ToddW850]

@Addicted don't worry about it, I've had cracks there for years. Okay not really. But I purchased my boat beginning of 2013. Noticed the same thing shortly thereafter. Mine is only at one of the bolts. My opinion was the jet pump had been removed for whatever reason by the previous owner and reinstalled and got over tightened. I'm no expert but I never considered this anything more than a gel coat crack and haven't worried about it. I boat literally almost every weekend in season and I have not noticed any issues related to this. Nor have I noticed any changes in the cracks (length, size, etc).

But just out of caution now, after reading concerns on here, I may slide some silicone into the small cracks, if it will go. Or I may keep some wax on it. But again, I've not noticed any issues related to this.

 

[CrankyGypsy]

@Addicted i'm currently in the process of going through my entire boat and fixing all my gel cracks. looking at it optimistically, gel is more brittle than FRP (fiberglass) so it could easily be superficial. i'm still a newb at FRP repair and am erring on the side of caution: just assuming all gel cracks are caused by underlying fiberglass stress because there are some i HAVE to do, so i'm doing them all at once. in some cases, i've actually found areas in the factory-layup of FRP that have small "air pockets" which are obviously weaker and may have attributed to the cracking. what i'm doing is using Dremel bit #117 to grind out the cracks, fill with a vinyl ester resin/fumed silica/loose mat fiber mixture ("peanut butter"), and then gelling over it. i'm usually really good at overkilling things, though. most of my cracks appear superficial, but they also tend to be in higher stressed areas, so that's why i am going this route.

that all being said, yours really don't look too bad to me and i would agree with @txav8r - especially if Yamaha isn't going to cover it and you don't really want to go through the hassle of removing the plate if you don't have to. even polyester FRP (the most water-susceptible of the resins) isn't going to readily absorb water unless it is compromised - as long as the resin is intact (ie: not cracked), infiltration of water with a boat on a trailer isn't going to be likely. i'm sure we all have similar gel issues, but i've not seen one thread regarding delamination or blisters on this forum.

now, @ToddW850 , your cracks seem a little deeper/wider than Addicted's. as a precaution, i think your idea of covering them would be a good idea until the day comes when you have a bigger excuse to pull the plate. and i'd not really worry about it until then unless the cracks spread.

 

[ToddW850]

Thanks @CrankyGypsy , I agree. My plan is to head to West Marine in just a few.

 

[Murf'n'surf]

Don't worry about them. Record your concern with your dealer. Make sure you get a hard copy of them checking the stress cracks (ie it should list this concern and a resolution on their invoice). If they turn it down you will have concrete proof that you gave them a chance to repair it if it should ever become an issue down the road.

I think its mostly cosmetic and will never progress further than what you see today.

 

[Bruce]

@Glassman, this is your kind of thread!

 

[Seadeals]

I don't see how over tightening the pump bolts after basic pump removal/install would stress the pump mount plate at the attach bolts through the hull where it shows the cracking. I could see cracking there if the through bolts (which are installed with sealant) are over torqued; but that would have happened at build. The pump mounting bolts thread to the mount plate, so no stress should transfer to the hull. Blunt force to the jet nozzle assembly could perhaps have stressed it enough to crack; but if both pumps have that; I can't see causative action being the culprit unless you like ramming her into the beach stern first all the time bumping your nozzles/fins...no one does that.

I found a manufacturing void between gel and glass on mine (photo). It was evident as a crack; but a quick tap test revealed the actual size, which was about the size of a quarter.

You can see how the glass was never compressed to the gelcoat surface. I opened it up and filled it in with chopped fibers and resin with some gel at the surface (overkill but practice for a similar repair I did at the bimini bracket). I would not be surprised if voids between the glass they layup and the gelcoat they spray are somewhat common. Coin tap the area by the cracks then on the glass inside to assure a consistent "crisp" sound. Overall, I say cosmetic; but since that area transfers the jet thrust to your entire boatload of fun, checking it on the inside for any signs of stress should give you peace of mind.

 

[Seadeals]

Also, see from this picture how prone the gel coat is to cracking around drilled holes. This is after I removed the factory transducer. If the tool to pilot the mount plate hulls was getting dull, small cracks in the gel coat around the hole could easily propagate over normal use. The fiberglass would have no issue, but the gel layer is more brittle and prone to it once small cracks are present. I am sure the cracks below we're not that big when the holes were drilled.

 

[Addicted]

I don't see how over tightening the pump bolts after basic pump removal/install would stress the pump mount plate at the attach bolts through the hull where it shows the cracking. I could see cracking there if the through bolts (which are installed with sealant) are over torqued; but that would have happened at build. The pump mounting bolts thread to the mount plate, so no stress should transfer to the hull. Blunt force to the jet nozzle assembly could perhaps have stressed it enough to crack; but if both pumps have that; I can't see causative action being the culprit unless you like ramming her into the beach stern first all the time bumping your nozzles/fins...no one does that.

I found a manufacturing void between gel and glass on mine (photo). It was evident as a crack; but a quick tap test revealed the actual size, which was about the size of a quarter.
View attachment 17530
You can see how the glass was never compressed to the gelcoat surface. I opened it up and filled it in with chopped fibers and resin with some gel at the surface (overkill but practice for a similar repair I did at the bimini bracket). I would not be surprised if voids between the glass they layup and the gelcoat they spray are somewhat common. Coin tap the area by the cracks then on the glass inside to assure a consistent "crisp" sound. Overall, I say cosmetic; but since that area transfers the jet thrust to your entire boatload of fun, checking it on the inside for any signs of stress should give you peace of mind.

I agree with you. The problem was not from me over tightening the pump assembly. I think that the torque in that area has caused my cracks, or more likely expanded hairline cracks caused by installation. I am thinking if it were purely from install, I would have seen them sooner, and there would likely be cracks around the lower bolts as well, or at least some of them.

My fins and pumps have never hit anything, I am sure of that.

Seeing your cracks not comforting. Thanks for the advice, I will get under there and explore a little further.

 

[Glassman]

@Glassman, this is your kind of thread!

I posted something about a new product a while ago...

https://jetboaters.net/threads/hairline-cracks-spider-cracks.1590/

At the time of posting I hadn't tried it out, but since then I have. As in the link MOA_Chaser posted at the end of the thread above, you can see the before and after pictures another boater took. It worked.

It worked for me too, in fact the hairline crack stuff is fairly liquid and designed to flow - so not very good for big, deep repairs BUT I used it for just that one day to repair a rather large , deep scrape. I was impressed at how well it hung in there. I had to do it progressively, but it worked well.

Ordinarily I would simply use gel coat and thin it and catalyze it accordingly, but for this being a one tube - easy application I give it a thumbs up!

 

[Addicted]

Thanks for the lead. That appears to be the perfect fix.