Outboard Motors
These remarks are intended for motors used on a Hartley TS16. And are intended as guide, not an official comment.
Power The first point to remember when talking of the power rating of a motor is its age. Old motors, such as the 1970’s popular Johnson & Evinrude 6hp, had the power rated at the flywheel, whereas to-day’s motors are rated at the propeller. So in rough terms, the old 6 is equal to to-day’s 4.
Long or Short Long is preferable, for while a little heavier than a short, there is extra weight in the bracket for a short if it is used. The problem with a short is its tendency to lift out of the water in a chop or wash, which is not good for it.
Fuel supply Some smaller motors have integral tanks of 1-2 litre capacity, generally good for 45/70 minutes of running in smooth waters, depending on the throttle setting. Some only use external tanks, and others have the facility to have both.
Power A (new) 3.5/4hp motor will mover a Ts16 quite comfortably through the water in all but a howling gale. Some use 6 and 8 hp motors, which then give a comfortable reserve of power. However, as power goes up, so does the weight.
Weight The small3/4 hp motors generally weigh around 12-15 kilos. Once past this point, the weight jumps into the 22k plus range. It is the feeling of many TS16 people that this boat should not be trailed with the motor on the transom, and therefore consideration must be made for lifting in & out of the car boot and on to the transom. And also for being able to stow it forward of the mast if carrying it while sailing.
Bracket The disadvantage of an adjustable bracket being used with a short motor is firstly its weight. When sailing, if the motor is tilted while the bracket is down, the propeller tends to drag in the water, particularly if the boat is heeled. And if the bracket is up, with the motor tilted, there is a change to the centre of gravity, and therefore the balance of the boat in the transom area, which could become dangerous if sailing in strong winds.
The other BIG disadvantage of the bracket is that if the motor hits an obstruction the extra leverage can cause severe damage to the transom.
General comment Johnson made an excellent twin cylinder 4hp motor about 8-10 years ago. It is smooth, quiet, and has both integral & external tanks, and is quite powerful enough to move a TS16 comfortably through the water – in fact, I have towed two other TS16’s a considerable distance on one occasion. Some members are using Tohatsu 3.5 long motors, or Mercury/Marina 4hp (cut back 5) motors, but the single cylinders can be noisy & rough if not well cared for.
Speed The design speed of a Hartley TS16 hull is around 5 knots, and the 3.5/4hp motor will meet this comfortably. To get the hull on the plane, you would need a considerably more powerful motor, and the rear end of the boat would not last too long in heavy conditions, particularly without strengthening.
End of day -Shannon Outboard Services advise that when you have finished with your two stroke for the day, it should be run in fresh water for about 10 minutes at idle, then the fuel cut off, and the motor left to run at idle till the carburet is empty. At this stage the motor should not be accelerated.
When fuel is left in the carburet, the petrol will vaporise and leave a residue which in time will cause blockages & starting problems.
As the boat is designed primarily for sailing, the motor should be considered as an auxiliary source of power for quiet estuary & river cruising, or getting home when the wind has dropped.