Severe damage to boats often require structural repairs. It is important to determine if your damage is structural or cosmetic.
In general, structural damage involves the disruption of the laminate system of the boat's construction. This can be observed as major cracking or gouging. This damage can also be caused by major impacts or serious abrasions. In order for these types of damage to be considered structural, they must compromise the integrity of the hull.
Cracks appear in fiberglass boat hulls in areas of abnormally high flexing. This can be caused by a number of things.
First, the hull may have been overloaded, or caused to bear a load in an unintended area. Heavy accessories like outriggers, seats, and T-Tops are intended to be located on reinforced areas of the hull. If they are installed incorrectly or in the wrong spot, the fiberglass is unable to support the additional load without damage, and cracks appear.
Flexing and cracking also accompany a deterioration of a boat's core structure. If the wood core of a boat rots, additional stresses may be placed on the fiberglass deck, causing flexing and cracking. This is highly dependent upon the materials and construction methods for each boat model.
Gouges are usually the result of a sharp object scraping the hull. In order for gouges to be considered structural damage, they must be deep enough to have broken a considerable portion of the fiberglass cloth strands and be long enough to affect a major load-bearing portion of the boat.
Sometimes serious gouges show signs of cracking around the original damage point. If this is the case, consider the damage to be structural, and repair immediately.
Impact damage is caused by -- You guessed it -- foreign body impacts to the hull.
Things hit the hull frequently, but luckily only a small portion of these impacts do any damage. An even smaller portion do damage that is structural in nature.
Impact damage should be considered structural if it penetrates the laminate and exposes more than a few inches of the hull's core. Cracks often appear near impact sites, and should be dealt with. These structural repairs are usually straight-forward and can be completed quickly.
Abrasions also occur very frequently. From beaching runabouts in high surf to misplacing a fender while docking - abrasions can do UGLY damage to our boats.
Serious abrasion is a double-threat to the integrity of our boats' structure. First, breaking down the barrier of gel-coat or paint exposes the hull's fiberglass to damage. Water and sunlight can quickly break down unprotected fiberglass. Also, abrasions sometimes go all the way through the fiberglass and damage the hull's core, be it wood or foam.
Under these circumstances, it is important to reduce the exposure by beginning repairs quickly!