Most boats are supported by lengths of wood on its bottom. These wood lengths are what are referred to as stringers. Stringers are prone to wear and tear due to the harsher treatment they get so they are to be repaired or replaced often.
Unsealed Deck Holes
If someone has bedded something in the deck and not sealed it properly, the water will be able to get through that hole and will rot the wood stringer on the boat. When there is rot in the stringer, it’s just a matter of time before it fails, and the stringer falls apart. Whenever you discover this, the first thought should be to check the stringers if they’re not boxed in.
Delaminated Fiberglass
Where the fibreglass of the deck has become delaminated, it’s almost certain that water will have penetrated the stringers. Whereas a deck hole can mean the replacement of just one stringer, deck delamination will usually involve putting in all new stringers. This is a major job, which will mean removing and replacing the entire deck as well as the stringers. This will not only be time-consuming but also very expensive, and keep the boat out of the water for a long time.
Sourced from: http://www.doityourself.com/stry/7-signs-its-time-to-fix-your-boat-stringers#b
Fiberglass in the boat can break but this should not be disheartening since this is a material that can be repaired easily. You do not need a professional to do the repairs for you as far as fiberglass is concerned. There are DIY tips that you can use.
Cut Away the Damage
Impact damage nearly always results in some associated delamination. Tap the impact area with the end of a plastic screwdriver handle to determine the extent of the damage; solid laminate sounds sharp, delamination dull. Check inside the boat to make sure nothing is in the way, then make a circular or oval cut to remove the damaged area. Never try to save damaged fiberglass; always cut it out and replace it with new laminate. Check all the edges and enlarge the hole if you find any additional delamination.
Working from Inside
If the damage area is small and above the waterline, make the repair from inside the hull, if possible. You are going to bevel the edge of the hole with a 12-to-1 chamfer, so if you repair a 3-inch diameter hole through a 1/2-inch-thick hull from the outside, you end up with about 15 inches (diameter) of surface damage to refinish. Repair it from the inside and you have only a 3-inch hole to refinish.
A second reason to make the repair from the inside is that you can back the hole on the outside with a polished surface, creating a mold that allows you to lay-up the repair the same way the boat was built–gelcoat first. Very little finish work will be required.
Sourced from: http://www.boatus.com/boattech/casey/fiberglass-repair.asp
Times are tough financially and many boat owners prefer doing their own repairs instead of hiring professionals. It is advised that one effective way of minimizing coats is by painting the boat’s bottom. For those who have their boats on trailers this is a nightmare thus the need to know how to get your boat off a trailer.
If you use a roller trailer, you should block up the boat for winter storage. If you don’t, the rollers will leave small indentations in the hull and possible stress cracks in the area of the pressure points . The rollers straddle the main stringer of the hull; they don’t sit on the stringer like a bunk trailer. Also, if you trailer the boat a long distance to use it during the summer, it’s best to use a bunk trailer.
Invest in boat stands. New, they run around $75 each; used, about $25 each.
Look for 12″ x 12″ pressure-treated wood blocking. Do not use cinder blocks if you’re working on the bottom of the hull. If you can’t find the correct size blocking, you can use 6″ x 6″ pressure- treated wood from Home Depot or Lowes. You would glue two pieces together with Liquid Nails and then nail 12″ x 12″ x 5/8″ plywood to the ends to make them one 12″ x 12″ unit and to keep them square and locked in place.
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When blocking up a boat, do not use a three-point blocking stance. (See photos 1 and 2) For an 18-ft boat, you should have two main blocks under the boat and two boat stands on the port and starboard sides for a total of six contact points. Bigger boats require more blocks and boat stands (every six feet). So you will have eight contact points on an 20-Ft boat.