Spider Cracks in Sunfish Hull

[nc_beagle]

I've got a (late 80s/early 90s?) Sunfish that's developed spider cracks in the fiberglass hull. It has been stored for a long time on a trailer and does get water infiltration into the hull. I plan to give it an a similar one to a friend but don't want to give them a huge problem. Is this something I should address and if so, does this sort of repair cost a lot? Its in at least two areas, each about the size of a playing card.

Thanks,
Mark

 

[sail sfbay]

Welcome to the forum!!

Ouch.......below is a procedure to remove them:

• Move your boat to a well-ventilated area where it can be sheltered overnight.
• Clean the area. Clean the crack area with acetone. Use a rag to protect your fingers and to do a thorough job of removing dirt and debris that might have caught in the cracks. Even if you can’t see all of this debris, it has the tendency to build up and lead to discoloration.
• Sand down the area. An electric sander is optional here, especially if the affected area is still small. Feel free to make a judgment call here, as sanding by hand is easier and more affordable, but it may take you more time.
• Remove sanding dust. Once finished, remove all the dust from the sanding with the rag and acetone once more.
• Tape off and apply gel coat. After masking off the area with painter’s tape, use a paint brush to apply gel coat. Use a marine grade fiberglass resin and be sure to keep it in a separate container until it’s ready to apply. Once it is, make sure that the brush doesn’t have any loose bristles, and apply the gel coat carefully after following the directions on the gel coat package.
• Dry, sand, clean, rubbing compound, wax and buff. After allowing the gel coat to cure overnight, you can smooth the area out with sandpaper, clean out the sanded area, and then both prime and paint the fiberglass if the color’s off.

More detail in this video: How To Fix Spider Cracks, Hairline Cracks, and Crazing in Boat Gelcoat [MATERIALS LIST] | BoatUS - Bing video

 

[nc_beagle]

Welcome to the forum!!

Ouch.......below is a procedure to remove them:

• Move your boat to a well-ventilated area where it can be sheltered overnight.
• Clean the area. Clean the crack area with acetone. Use a rag to protect your fingers and to do a thorough job of removing dirt and debris that might have caught in the cracks. Even if you can’t see all of this debris, it has the tendency to build up and lead to discoloration.
• Sand down the area. An electric sander is optional here, especially if the affected area is still small. Feel free to make a judgment call here, as sanding by hand is easier and more affordable, but it may take you more time.
• Remove sanding dust. Once finished, remove all the dust from the sanding with the rag and acetone once more.
• Tape off and apply gel coat. After masking off the area with painter’s tape, use a paint brush to apply gel coat. Use a marine grade fiberglass resin and be sure to keep it in a separate container until it’s ready to apply. Once it is, make sure that the brush doesn’t have any loose bristles, and apply the gel coat carefully after following the directions on the gel coat package.
• Dry, sand, clean, rubbing compound, wax and buff. After allowing the gel coat to cure overnight, you can smooth the area out with sandpaper, clean out the sanded area, and then both prime and paint the fiberglass if the color’s off.

More detail in this video: How To Fix Spider Cracks, Hairline Cracks, and Crazing in Boat Gelcoat [MATERIALS LIST] | BoatUS - Bing video

Thanks. That's extremely helpful. I was worried it is deeper than the surface.

Just out of curiosity, could freezing of the water inside the hull contribute to my problem or cause other problems? I've never checked to see if the water froze, but where I live, we get down below freezing many times during the winter.

 

[jssailem]

Is this something I should address and if so, does this sort of repair cost a lot? Its in at least two areas, each about the size of a playing card.

Welcome Beagle to SBO.

What level of finish are you attempting to accomplish? This will play heavily into the calculation of Costs.

• Bristol is a standard of - As good or better than originally delivered by Manufacturer.
• Sound with color close to the aged surface and boat is fully functional
• DYI Aged Good Color of repair not a factor. Good repair of damage accomplished.

It all depends on you and what you want to complete.

 

[sailboatracer]

Just out of curiosity, could freezing of the water inside the hull contribute to my problem or cause other problems? I've never checked to see if the water froze, but where I live, we get down below freezing many times during the winter.

It's highly unlikely that water within your hull is contributing to the problem. The hull and deck are supported from within with blocks of foam. Water entering the hull is common. That's why there is a drain plug on the side of the hull. Unless the hull was completely filled with water, it will not cause a problem if it freezes. There is ample space between the blocks of foam within the hull for ice to expand into.

 

[sail sfbay]

...........could freezing of the water inside the hull contribute to my problem or cause other problems...........

In response to your first question, it is hard to say. Spider cracks can occur due a manufacturing defect, i.e., structural problems or severe impact damage How to Fix Cracks in Gelcoat on Boat Surfaces – Pensacola Shipyard. If you have water inside the hull, you will want to dry it out before you make the repair.