Why Boats Sink in the Springtime – The Common Causes

Launching a boat in the spring for a new boating season is normally a happy occasion, but some owners get a rude surprise instead — a sinking.  While not widespread, sinkings during re-launch at the dock are easily avoidable, said Bob Adriance, editor of Seaworthy , the magazine from BoatU.S. that helps boaters avoid damage and improve safety aboard their boats.  Here are Bob’s tips to avoid a springtime sinking:

•    Hose clamps:  Winterizing an engine in the fall often requires the removal of coolant hoses.  Come springtime, boaters are in a rush and the hoses aren’t reattached and clamped properly.  Adding to this, cramped engine boxes mean that the hoses and the clamps holding them sometimes can’t be visually inspected easily.  In the spring you’ll need to ensure all of the hose clamps are securely tightened in place.

•    Hoses:  During the winter as the water inside them freezes, some hoses can lift off their attached seacock (valve). However, with spring’s warmer temperatures the water now returns to a liquid, and if the seacock was left open last fall, water can pour into the bilge.  Double clamping with marine-rated stainless hose clamps, inspecting hose attachment locations, or keeping seacocks closed can all save you from a spring sinking.

•    Spring rains:  Combine heavy rains with leaking ports, deck hatches, fittings, chain plates and even scuppers clogged by leaves from last fall and you have a recipe for a sinking.  Just 100 gallons of water weighs over 800 pounds so a boat with a low freeboard only needs to sink a few inches before cockpit scuppers (drains intended to remove water) submerge and water starts to enter the boat.  Larger boats with cracked or improperly caulked fittings that are located just above the waterline can also inadvertently let water in when they become submerged.  Ensure that rain rolls off the boat and not into it.

•    Sea strainer:  For inboard/outboard and inboard powered boats, always inspect the strainer for cracks or other damage. If it wasn’t properly winterized, the intake sea strainer could have frozen over the winter, cracking or bending the inspection bowl.  And if the seacock was left open the boat will sink as soon as ice in the strainer thaws or the boat is put in the water.  Boats have also sunk when the seacock was closed over winter and then opened in the springtime, but the owner failed to notice water trickling into the bilge from a freeze damaged bowl.

•    Stuffing Box:  On powerboats or sailboats with inboard power, if the stuffing box’s packing material that seals the prop shaft is not tight, a steady drip could eventually swamp a boat if it’s ignored. Remember, the stuffing box should only leak when the prop shaft is turning.  Stuffing boxes need to be inspected routinely, regardless of the season.

BoatU.S. Spring Commissioning Safety Checklist

BEFORE YOU LAUNCH:
•    Inspect and lubricate seacocks.  Hoses and hose clamps should be inspected and replaced as necessary.
•    Replace deteriorated anodes.
•    Inspect prop(s) for dings, pitting and distortion. Make sure cotter pins are secure.  Grip the prop and try moving the shaft – if it’s loose, the cutlass bearing may need to be replaced.
•    Check to make sure the rudderstock hasn’t been bent.
•    Inspect the hull for blisters, distortions and stress cracks.
•    Make sure your engine intake sea strainer is free of corrosion, clean and properly secured.
•    Check the engine shaft and rudder stuffing boxes for looseness. After the boat is launched, be sure to check all through-hulls for leaks.
•    Use a hose to check for deck leaks at ports and hatches.  Renew caulk or gaskets as necessary.
•    If equipped, ensure that the stern drain plug is installed.

OUTDRIVES and OUTBOARDS:
•    Inspect rubber outdrive bellows for cracked, dried and/or deteriorated spots (look especially in the folds), and replace if suspect.
•    Check power steering and power trim oil levels. 
•    Replace anodes that are more than half worn away.
•    Inspect outer jacket of control cables.  Cracks or swelling indicate corrosion and mean that the cable must be replaced.

ENGINES AND FUEL SYSTEMS:
•    Inspect fuel lines, including fill and vent hoses, for softness, brittleness or cracking.  Check all joints for leaks and make sure all lines are well supported with non-combustible clips or straps with smooth edges.
•    Inspect fuel tanks, fuel pumps and filters for leaks. Clamps should be snug and free of rust.  Clean or replace fuel filters.  Owners of gasoline-powered boats with fiberglass fuel tanks should consult a marine professional to inspect for any ethanol related issues.
•    Inspect cooling hoses for stiffness, rot, leaks and/or cracking. Make sure they fit snugly and are double-clamped.
•    Every few years, remove and inspect exhaust manifold for corrosion.
•    Clean and tighten electrical connections, especially both ends of battery cables.  Wire-brush battery terminals and fill cells with distilled water (if applicable).
•    Inspect bilge blower hose for leaks.

SAILBOAT RIGGING:
•    Inspect swage fittings for cracks and heavy rust (some discoloration is acceptable).  Inspect wire halyards and running backstays for fishhooks and rust.
•    Remove tape on turnbuckles and lubricate threads, preferably with Teflon. Replace old tape with fresh tape.
•    Recaulk through-deck chainplates as necessary (generally, once a decade). If you suspect the core around the chainplate is damp, remove the chainplate to inspect and make repairs.

TRAILERS:
•    Inspect tire treads and sidewalls for cracks or lack of tread and replace as necessary.  Check air pressure.  Don’t forget the spare!
•    Inspect wheel bearings and repack as necessary.
•    Test tail and back-up lights and winch to make sure they’re working properly. Inspect hitch chains.
•    Inspect trailer frame for rust.  Sand and paint to prevent further deterioration.
•    Inspect brakes and brake fluid reservoir.

MISCELLANEOUS:
•    Check expiration dates on flares and fire extinguishers.
•    Check stove and remote tanks for loose fittings and leaking hoses.
•    Inspect bilge pump and float switch to make sure they’re working properly.
•    Inspect dock and anchor lines for chafing.
•    Update or replace old charts, waterway guides.
•    Check shore power cable connections for burns, which indicates the cable and/or the shore power inlet must be replaced.
•    Make sure your boating license and/or registration is up to date.  Don’t forget your trailer tags.
•    Review your boat insurance policy and update coverage if needed.  Be sure you have fuel spill insurance coverage.
•    Make sure you have a properly sized and wearable life jackets in good condition for each passenger, including kids.
•    Test smoke, carbon monoxide, fume and bilge alarms.
•    Be sure to get a free vessel safety check from the U.S. Coast Guard Auxiliary or U.S. Power Squadrons.