Boat Leaks

George Van Parys

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When will they ever build a boat that never leaks?

I suppose it depends on what you consider a leaky boat. Whether it's an accumulation in the bilge or just a wet aft cabin mattress, in either case, the sources are almost endless. Rain water, washing the boat, bath shower area moisture, hull and fitting leaks, engine leaks, condensation, beverage spills, holding tank leaks, sinks overflow, swimmers and water skiers, refrigerator and air conditioner condensate lines, fresh water system, etc. are all contributing factors on a regular basis.
The obvious question is, When does it leak? All the time, or only after some specific event. A little detective work could easily locate the source in no time at all. Sometimes it isn't easy to find and or fix the problem, but it is less expensive to do the detective work yourself than to try and pay someone to find it for you.

Leaks while running

Engine sources
Engine coolers
Wet Exhaust system
manifold or block cracks
hot water heater hoses and or fittings (some hot water heaters use the cooling water from the engine to heat the water you drink)
loose or missing engine block core plugs

Thru-hull fitting sources
Prop shaft
Rudder posts
Back flow from bilge pump or shower discharge fittings.
Loose depth sounder thru-hull fittings.
prop shaft strut bolts

Other sources
Speedometer tube between dash board and transom
water cooled air conditioner lines and fittings
air conditioner condensate pan drain
refrigerator condensate line
water tank and fitting leaks
Condensation on the hull itself

Topside leaks
rub rail
cleats
Safety rail stanchion bases
windshield seam and fasteners to the deck
external electric horn wiring under horn base
Anchor locker hatches and or bins
Cock pit drain fittings and hoses
spot light base
running light base
under wood, plastic or metal step pads
improperly located engine room vent covers

Testing for leaks Caused by rain and or washing of the boat should be tested with a hose to simulate the event. But don't just soak the whole boat. Isolate your testing to a small area at a time. Since water can flow a long way from where it enters the boat to the place you notice it. And don't be in a hurry. Give the water a chance to flow because sometimes dirt collects in cracks and holes and will repel water for a short time until the dirt gets saturated with water. Removing cushions, carpet and panels from the test area and the use of a screw driver and powerful flashlight are the only tools you will normally need.

Testing for leaks in sanitation systems.
One quick thought to get you started on this topic is that even if you smell an odor from the sanitation system, that doesn't mean it is leaking. Some sanitation hose has a tendency to absorb the smell from its cargo and will have to be replaced to solve the problem. You could try flushing and soaking the system with chlorine to see if this is your problem, but usually this only lasts a short time. Over the years manufacturers have done a better job of solving this problem, so it might be a good idea to just replace the sanitation hoses.

A short note about hull delamination and balsa core saturation.

Although somewhat rare, the following two leak sources should be considered.
Some boat hulls and or decks, have a balsa core between two or more layers of fiberglass. Thru hull fittings and holes drilled into and thru this type of structure are hard to seal and can water log large sections of the laminated balsa. Any fitting or hole run thru balsa laminates should be sealed and reseal every few years to reduce the chance of balsa saturation and subsequent deterioration.

Delamination on the other hand is a structural fault in the hull caused by impact or abuse that has separated the layers of fiberglass laminate. Delamination isn't usually a vertical crack. Think of it as being similar to corrugated or laminated cardboard, where the center of the laminate has been crushed or has disappeared. Water running between delaminated fiberglass panels can travel a long way before it emerges into the boat.
 
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