Gelcoat Crack

[Bobby P.]

We are having a great time transiting Long Island's Great South Bay.
While underway, I noticed a hair-line crack in the gelcoat about 3 inches from the mounting base of the table that is located on the foredeck. The crack is very thin (hair-line) but is about 8-10 inches long. This crack is not a result of abuse or neglect. The Boat is a 2017. Any suggestions? We bought the boat pre-owned, with about 67 hours on it. Did not notice this crack prior to purchase, so I am pretty certain it is new.
Thanks,
Bobby

 

[BradOwens]

With it being so close to the table, I wonder if someone leaned on the table creating a lever action on the table support tube.
Whatever the cause, fiberglass repair kits are available at most marine supply and RV supply stores, and at Home Depot or Lowes. A hairline crack is easy to fix.

 

[BB marine]

Gel Coat cracks are common to areas around fasteners. When ever a fastener is installed in fiberglas with Gel Coat a relief cut should be made tapering the fasteners hole. If this isn't done when the fastener is tightened it can crack the Gel Coat. Over time the crack will start to migrate out from the fastener hole. The crack is cosmetic and is not structural so no need to be alarmed. I have several small stress cracks at fastener locations on my Cutwater. The proper repair requires grinding the crack out and filling it then Gel Coat. I personally don't mess with them unless the gel coat finish starts to chip and delaminate from the fiberglass. None of the cracks have done that on my boat yet.

 

[Bobby P.]

Thanks for this feedback. I found another hairline crack on the non-skid where people boarding should step. It's just a bummer to have a few of these on a boat that is only 2 years old. Nonetheless, we are enjoying the boat very much!
Bobby

 

[Boatagain]

Brian, i’m not sure I understand what you mean by a “relief cut...tapering the fasteners hole”. Can you explain?

 

[BB marine]

Mounting hardware to fiberglass with a Gel Coat finish requires drilling the proper size hole for the fastener being used then a taper cut should be cut in the Gel coat widening the hole at the gelcoat surface to prevent the fastener threads from catching the gel coat and cracking it. I use a taper burring bit after drilling the fastener hole

 

[Boris the Tug]

Seems like every time I wash my boat I find another crack. She is ten years old though.

 

[scross]

Age and gel coat cracking are a fact of life with gel coat over fiberglass. The gel coat is stiffer than the glass and doesn’t flex when the fiberglass does. This fiberglass flexing will lead to crazing or cracking of the gel coat surface. No practical way to completely stop it other than removing all the gel coat and then painting. Once the cracking and crazing start the water and sunshine make the surface problems worse. I’ve refinished several fiberglass sailplanes with crazed gel coat and it’s a very labor intensive process. The more the flex on the fiberglass the faster you have cracking or crazing.
In a boat, the faster you go the more likely you are to flex the fiberglass and crack the gel coat. My 10 year old Monterey Cruiser ( think Sea Ray Sundancer) was riddled with cosmetic crazing from go fast flexing and trailering
The process Brian outlined is good for slowing the progression of stress point related gel coat cracking. Sanding and polishing surface gel coat crazing will work until you have sanded completely through the gel coat.
You have a boat constructed using gel coat on top of fiberglass. Cracking and crazing over time is a given. Going slower, limited trailering and then sanding, filling, polishing with lots of wax at the first sight of cracking/crazing are your best and only real options.
Edited to correct spell check. I hate spell check!

 

[SLyle01]

Just noticed a 5" horizontal scrape on upper stbd. bow, just below the rub rail (of course). Didn't hit anything I'm aware of (who knows) but it's not thru the blue gelcoat...just a surface scrape, but too deep to buff our by hand. Suggestions for handling such touch-ups (and likely more, hopefully as small in the future) welcome.

 

[Matty]

There a number of youtube videos on why they occur and how to easily repair. Watch a few and see which method you want to use. seeing it done on video might be easier to comprehend than reading about it.