Chapter 13 Engines for Sailboats

Lesson Objectives Outboard engines for sailboats Two stroke vs. 4 stroke Engine maintenance/troubleshooting Inboard engines Diesel vs. gas Diesel maintenance Electrical systems SSSpptChpt13EnginesforSailboats040609.ppt

Outboard Characteristics Outboard engine: May be lifted out of the water when not in use Readily removable for service and repair Uses no cabin space Newer engines are very reliable SSSpptChpt13EnginesforSailboats040609.ppt

2 Stroke Versus 4 Stroke 2 stroke: crankshaft turns once per power stroke 4 stroke: turns twice per power stroke 2 stroke is lighter-more power per weight 2 stroke: lubricating oil is pre-mixed with gasoline and burns (white smoke) 2-stroke pollutes more than 4-stroke SSSpptChpt13EnginesforSailboats040609.ppt

2 Stroke Vs. 4 Stroke 4 stroke: more expensive & heavier per horsepower 4 stroke: oil in sump & pumped thru engine 4 stroke more reliable, quieter, and more efficient Less polluting SSSpptChpt13EnginesforSailboats040609.ppt

Outboard Maintenance Change lube oil as recommended Change spark plugs Change lower unit oil Don’t use old fuel SSSpptChpt13EnginesforSailboats040609.ppt

Inboard Engines Generally used in larger sailboats Can be very quiet with low vibration Requires additional safety precautions Requires a transmission and stuffing box Requires a cooling system Open system-sea water circulates through engine and back to the sea Closed system-sea water circulates through heat exchanger and back to sea SSSpptChpt13EnginesforSailboats040609.ppt

Stuffing Box Allows propeller shaft to rotate while preventing water from leaking into boat Cools itself if properly adjusted Some types are drip-free Wear out over time and need repacking SSSpptChpt13EnginesforSailboats040609.ppt

Diesel Engines More costly and heavier than gas More reliable and fuel efficient Less dangerous—diesel fuel is not explosive like gasoline SSSpptChpt13EnginesforSailboats040609.ppt

Diesel Maintenance Less maintenance than gas engines No spark plugs, distributor, carburetor Most problems are fuel-related contamination– dirty fuel and algae Starter motor has heavier starting load Good battery charging system & electrical connections SSSpptChpt13EnginesforSailboats040609.ppt

Batteries One for engine starting, one for accessories Battery switch-“Off, 1, 2, Both” Battery must be protected, secured & vented Deep cycle battery allows repeated discharge Clean battery connections are important SSSpptChpt13EnginesforSailboats040609.ppt

Battery Charging Long periods of being unused are hard on your battery Under charging and over charging are equally bad Float versus trickle charging SSSpptChpt13EnginesforSailboats040609.ppt

Shore Power 120V shore power grounding problems Electrolysis can cause major problems Nearby boats can cause damage Portable testers are available Consider GFI protection for on-board systems SSSpptChpt13EnginesforSailboats040609.ppt

Sailboat Propellers (with Inboards) Propeller drag affects performance Folding propeller is an option SSSpptChpt13EnginesforSailboats040609.ppt

Prop Walk Right hand props pull stern to port (slightly) Prop walk is obvious when in reverse before the boat has a chance to gain sternway More pronounced in full-keeled boats Use a short burst of reverse power to pull stern to port when docking SSSpptChpt13EnginesforSailboats040609.ppt

Propeller Maintenance Vibration usually indicates need for propeller and/or shaft repair Guard against galvanic action Sacrificial zincs prevent erosion of bronze propellers Check annually SSSpptChpt13EnginesforSailboats040609.ppt

Tool Kit An entire trip can be ruined for the lack of a simple tool or part Carry spares for all expendable items and tools to change them Fuel filters, drive belts, water pump impellers, oil filters, fuses, lamp bulbs, etc. Common tools: wrenches, screwdrivers, pliers, sockets, various stainless steel screws, hose clamps, zip ties, etc. spray lubricants (WD40) SSSpptChpt13EnginesforSailboats040609.ppt