Re: [Amel Yacht Owners] Gel Coat Cracks adjacent to the backstays & other assorted questions
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From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Friday, March 10, 2017 7:07 AM
Subject: [Amel Yacht Owners] Gel Coat Cracks adjacent to the backstays & other assorted questions
At the transom/hull joint on both sides the gel coat is cracked from top to bottom. While we're in a boatyard I'm thinking of doing a repair, so I'm soliciting suggestions on the repair method. THE REASON THE GEL COAT WILL CRACK IN THIS AREA ON ALL SUPER MARAMUS IS SIMPLE. THE ACTUAL TRANSON ITSELF IS A SEPARATE MOLDING FROM THE REST OF THE ONE PIECE HULL. THE TRANSOM IS INSTALLED AFTER THE OTHERWISE COMPLETED HULL AND DECK ASSEMBLY HAVE BEEN LAMINATED TOGETHER INTO ONE PIECE AND REMOVED FROM THE MOLD. THE TRANSOM IS MOUNTED THEN LAMINATED TO THE AFTER ENDS OF THE HULL AND DECK. AMEL DOES NOT DO EVERYTHING ABSOLUTELY PERFECTLY. IN THIS CASE, AFTER THE TRANSOM IS LAMINATED AND CURED, GEL COAT IS APPLIED TO THE AREA WHERE THE EXTERIOR OF THE TRANSOM JOIN IS. AMEL SIMPLY USED TOO THICK/TOO MUCH GEL COAT IN THIS AREA TO “FAIR AND FLUSH FIT” THE EDGES OF THE TRANSOM. IN A MORE PERFECT APPROACH, AN APPROVED FAIRING COMPOUND SHOULD BE USED, AND THEN THE PROPER THICKNESS, ABOUT 20 MILS, OF GEL COAT, SHOULD BE APPLIED.
THE REASON THE GEL COAT CRACKS IS BECAUSE IT IS VERY BRITTLE. WHEN APPLIED TOO THICKLY, IT EXACERBATES THE TENDANCY TO CRACK AS IT BECOMES EVEN MORE BRITTLE THE THICKER THE FINISHED GEL COAT SKIN BECOMES.
THE CRACKS BEGIN WHERE THE MIZZEN BACKSTAYS ARE ATTACHED AS THIS IS A POINT LOADED AREA WHICH ENCOURAGES THESE TYPES OF CRACKS. I HAVE NEVER SEEN THE LAMINATE IN THIS AREA WHERE THE CRACKS APPEAR DAMAGED IN ANY WAY BY THE MOUNTING OF THE MIZZEN BACKSTAYS THERE. I HAVE SEEN IT SEVERLY DAMAGED BY THE MOUNTING OF DAVITS, SOLAR/RADAR ARCHES, AND POST MOUNTED WIND GENERATORS WITHOUT PROPER REINFORCEMENT TO THE INSIDE OF THE TRANSOM.
IT IS EASY TO CHECK THE LAMINATE IN THIS AREA FOR DAMAGE. AT NIGHT, TAKE A POWERFUL SEACHLAMP AND HAVE A HELPER SHINE IT CLOSE TO BUT NOT TOUCHING ON THE EXTERIOR OF THE TRANSOM-HULL JOIN WHILE YOU CLIMB INSIDE A HOPEFULLY LESS THAN FULL STERN LOCKER. THE BRIGHT AND POWERFUL LIGHT WILL ILLUMINATE THE LAMINATE JUST LIKE AN X-RAY AS AMEL DID NOT APPLY ANY GEL COAT TO THE INSIDE OF THE TRANSOM. IF THE LAMINATE IS DAMAGED, IT WILL APPEAR TO HAVE MOVED AS INDEED THAT IS WHAT IT DOES WHEN IT FAILS. HAVE A REAL EXPERT TAKE A LOOK IF YOU ARE NOT SURE. COST CUTTING? NOT AT ALL. THEY DIDN’T APPLY GEL COAT TO MAKE THIS PANEL MORE TRANSLUCENT ALLOWING MORE LIGHT INTO AN AREA WHICH WOULD BE OTHERWISE QUITE DARK. ALWAYS THINKING, THESE AMEL PEOPLE! PLEASE, DO NOT TRY TO DO THIS BY YOURSELF BY PLACING THE SEARCHLAMP DIRECTLY ON THE TRANSOM THEN CRAWLING INSIDE AS YOU WILL SEE THE LAMINATE FAIL RIGHT BEFORE YOUR EYES BECAUSE POLYESTER RESIN STARTS TO FAIL/CRYSTALIZE AT 175F AND WILL CATCH ON FIRE AS IT GASSES WITH THE APPLICATION OF EXCESSIVE HEAT. TRUST ME. DON’T DO IT ALONE.
I've read here that these cracks happen on most SM's, and looking from inside the lazaret, it appears they are in the gel coat only. I am a bit concerned that these cracks were not reported on the 2015 pre-purchase Survey in any form, as if they weren't there then. I think they were there then, but don't know if they have gotten worse. DUANE, DESPITE THE DIFFICULTIES YOU HAVE EXPERIENCED WITH YOUR BOAT, THE PREVIUOS OWNER WAS A STICKLER FOR SYSTEMS MAINTENANCE AND COSMETIC UPKEEP. SINCE WE WERE GOING TO USE THE BOAT AS OUR SHOWBOAT IN THE MIAMI BOAT SHOW, I HAD THE CRACKS REPAIRED AS THIS COSMETIC ROUTINE WAS NOT HIDING ANYTHING THAT WAS WRONG WITH THE LAMINATE. THE GEL COAT GUY WAS EXPERIENCED. I TOLD HIM TO REALLY SAND DOWN THE OLD GEL COAT IN HOPES THE NEW GEL COAT WOULD NOT BE TOO THICK AND PRONE TO CRACKS. THERE WERE NO CRACKS THERE WHEN YOU AND PEG BOUGHT YOUR BOAT, YOU DIDN’T MISS ANYTHING. HE JUST PUT ON TOO MUCH GEL COAT. AGAIN.
The fiberglass repairman working on the boat (collision damage) suggested "radical surgery" including grinding off the gel coat over a wide area on both sides of the crack, adding fiberglass and then new gel coat. His opinion was if he just repaired the gel coat it would only crack again. Then he pointed out several areas where the gel coat had been "touched up" to hide the crack, only to subsequently crack in the same place. MY EARS PERK UP AND MY THINKING CAP GETS PULLED ON TIGHT WHEN ANYONE SAYS ‘RADICAL’. IF HE SUGGESTED ADDING FIBERGLASS AFTER GRINDING OFF THE GEL COAT, TO THE OUTSIDE, THAT WOULD BE A LESS THAN SATISFACTORY REPAIR. ADD STRUCTURAL FIBERGLASS TO THE INSIDE OF THE TRAMSOM WHERE A BETTER OVERLAP/MORE STRENGTH CAN BE ACHIEVED. THIS IS ESSENTIAL IF ADDING THE AFOREMENTIONED EQUIPMENT .
I can see there is some water intrusion on the stbd side at the crack. I'm thinking of filling it with Marine-Tex. I don't want to damage the structural laminates below, so any grinding/prep would be limitied to opening the gel coat crack to 1/8" or so. <<<Any thoughts about that?>>>IN MY EXPERIENCES WITH THIS CHALLENGE, I HAVE FOUND THAT SANDING THE GEL COAT OFF, CAREFULLY AND SLOWLY SO AS NOT TO CHEW INTO STRUCTURAL LAMINATE, FOLLOWED BY PROPER APPLICATION OF A COMPATABLE PRIMER FOLLOWED BY POLYUREATHANE PAINT WITH AN ELASTOMER ADDITIVE MAKING IT VERY RESISTANT TO SURFACE CRACKS WORKS NICELY AND LASTS A LONG TIME AS IT DOES NOT OXIDIZE AS MUCH AS GEL COAT. THE ONLT NEGATIVE PAINT HAS TO GEL COAT IN THIS APPLICATION IS THAT GEL COAT CAN BE SANDED IF SCRATHED, PAINT COMES OFF AND MUST BE REPAINTED. THE PERFECT TIME TO DO THIS ALMOST PERMANENT REPAIR IS WHEN A NEW OWNER BUYS THE BOAT AND RENAMES IT. IF THE PREVIUOS NAME ON THE TRANSOM HAS BEEN THERE FOR YEARS, IT WILL BE PRETTY HARD TO ELIMINATE THE GHOSTING THAT THE AREA UNDER WHERE THE OLD NAME WAS. PAINTING THE ENTIRE TRANSOM KILLS TWO BIRDS WITH ONE STONE.
I'll take some photos after the sun comes up.
I'm up early with sore muscles/joints after buffing and polishing the boat the last three days, and I'm only half done! The red gel coat on the rubrail was terribly oxidized, but I've been able to get it back to "pretty good" with some aggressive rubbing compound and then a polishing compound. The bootstripe also got the same treatment and looks great now. I used the polishing compound on the white gelcoat and that seemed to even out the color. I just started waxing! yesterday afternoon. I've used the Collinite Fleetwax before and it would last a year on a freshwater lake. I'll see how it goes in saltwater. <<>> DUANE, THAT’S WHAT HIGH SCHOOL DROP OUT BOATYARD WORKERS ARE FOR. I WONT ARM WRESTLE YOU FOR A FEW WEEKS…
One of the yard workers recommended "Marykate On&Off Hull&Bottom Cleaner" for the scum line. It says it also removes the diesel soot smudge. I have had trouble removing that smudge with ANY cleaner. Last time I worked on that in the water I had to use a rubbing compound by hand. <<<>>>THAT STUFF REALLY WORKS. SOME GEL COAT SUPPLIERS RECOMMEND AGAINST USING IT. DON’T HAVE DEFINITVE ANSWER FOR YOU.
Thanks, MY PLEASURE