Spider Cracks

eric_hogue 12-15-2004, 5:35 AM

Had a tower installed last night on 93 MC ProStar. When we were tightening one of the rear mounts the backing plate pressed up at an angle and created about 7 spider cracks in the gelcoat about .75 of an inch long. Should I be concerned about these. The guy who built and installed the tower offered to have it fixed, but I am not sure if it is really necessary. Are they just cosmetic? He offered some (4) custom speaker cans he made if I did not want to get it fixed.

(wakehound) · (wakehound) **Join Date: Oct 2003** 12-15-2004, 11:14 AM

Can you tell if they're just in the gel, or did they go through the fiberglass? I'd at least have it checked out to make sure it's still structurally sound to support the weight and force of the tower. Don't need to have your tower pulling out of your hull, know what I mean?

(mastercraft1995)

Get it fixed unless you want to have big stress cracks going down the side.

eric_hogue 12-15-2004, 11:59 AM

Mark B- I don't think it could possibly be in the glass. When we drilled the mounting holes the glass over a quarter inch think and the mounting plates are 3 inches wide and 6.5 inches long so the surface area covered is pretty substantial.

face planter - is that advice from experience?

(mikeski) · (mikeski) **Join Date: Aug 2003** 12-15-2004, 12:10 PM

Post pix please

(mastercraft1995)

On a friend boat. It's kind of like steel if you don't stop drill the crack it will continue until it get to the other side.

(wake_upppp) · (wake_upppp) **Join Date: Nov 2003** 12-15-2004, 7:02 PM

I'de just take a wait and see approach. The rear mounts have no risk of pulling out since pressure is applied downward on them. Not all cracks will continue to wander either especially if it's just in the gel coat. Depending on the amount of stress and movement of the area, it may or may not continue to crack.

jmo52 12-15-2004, 10:13 PM

When gel coat gets old it gets more brittle and will crack. You would have to really torque down to crack the actual fiberglass. Thats not to say that the gel coat cracks wont keep growing as time goes on and water and sun have their way with it . As far as it not being strong any more I dont think thats the case.

(da_moose) · (da_moose) **Join Date: Feb 2004** 12-21-2004, 12:52 PM

It sounds to me its just cosmetic ,if you put up a picture I can tell more.I've been doing gelcoat repairs for over 25 years .take some super glue and wipe it on the cracks {put a glove on your hand or you will be part of the boat}This will seal the cracks

(ramhouse) · (ramhouse) **Join Date: Apr 2004** 01-03-2005, 11:43 AM

Your backing plate should be absolute flat on the under side!!!!NO GAPS...Your boat need to be reinforce on the under side..A $200.00 glass job on the 90's MC is a MUST!!!The top deck of your boat needs to be gussetted to the hull..if you remove the rubber bumper you will notice that it is only pop rivited together. It will come apart.
If you would like some pics of the work i will be happy to send you some...extra glass is cheep insurance..and yes the crack will end up on the othe side of the boat. I would have them fix it and do the extra glass work for free..My "93 is in profile..let me know if you want pics...

(guido) · (guido) **Join Date: Jul 2002** 01-03-2005, 1:32 PM

My '02 sanger has stress cracks around the tower mounts from normal use, and its not the first boat that I've seen that way. They didn't spread last year after I noticed them. I wouldn't be too worried. As long as the tower mount correctly matches the contour of the deck of the boat it wouldn't concern me. You can always get them fixed down the road. The question of the top deck of the MC being riveted is another issue all together. Good luck with that. It's kinda common for the top deck to seperate on a boat thats used hard.