By John Siwicki Many forces act upon a boat (especially sailboats) and they need diligent maintenance. It is not financially practical to have every boat you are interested in surveyed, so you want to do the initial inspection yourself and try to spot any major problems. The main and most critical component of a boat is the hull. It keeps the vessel afloat and can be the most costly to repair. A good eye and some simple tools can help spot potential problems. The first step is to stand at the bow and stern and look along the sides of the hull for irregularities while slowly moving side to side and up and down. Bring a clear grid or a straight edge to help determine if the keel and/or rudder are misaligned.
The next step is to look for stress cracks. Random eggshell-like cracks (crazing) are common surface defects and typically do not indicate structural damage. Stress cracks are usually in a pattern and can indicate a collision or can be a result of inconsistent building practices from the factory. They can cause a void between the layers of fiberglass, water can get inside and create a chemical reaction, temperature fluctuations make the area expand and contract and the area becomes damaged. Tapping on the hull with a sounding hammer or the plastic end of a screwdriver can reveal delamination. By tapping around on the hull, and especially around the stress crack area you will hear a change in sound from a sharp percussive sound to a dull thud, which would indicate the delaminated area.
Anything can be fixed. However, the cost or effort may exceed the value in terms of time and investment. All previously owned boats will have some moisture in the hull and deck. An investment in a moisture meter is a topic of great debate. The readings can be misleading and there are variables such as bottom paint that can throw off the reading. At best, a moisture meter can tell you areas that are wetter (ie. around fittings) relative to other areas. The deck is another critical area. It carries the weight of people walking around and is the primary attachment point for components such as handrails, cleats, wenches and other deck hardware. By walking around on the deck, you can feel soft spots that indicate separation. Tapping and checking with a moisture meter are other methods of determining if the deck is solid and structurally safe. You can learn more about blisters by clicking on the following article: http://www.yachtsurvey.com/BuyingBlisterBoat.htm