Saving Old Seagulls

My 102 takes about 1.7 liters per hour when running 50% to 60% throttle. That is enough for normal speed. Quiet waters around 4 knots. Running at full you take more fuel and there's not very much speed extra. If you want to be very economic: run it at 30% throttle. Then it takes almost 2 hours to empty your tank with a speed of around a 3 to 3.5 knots. My longest run was about 10 hours. Of course no problems at all. We spend our holidays with our Drascombe Longboat Cruiser 22 feet called Seagull. Our engine is a BS 102. Enough for such a boat. Last summer we beat 4 feet high steep waves in Bf 6. Other owners say you need at least 6 Hp, 8 is even better......they just waste power in my opinion.

Refuelling: my wife is motoring and I refill the tank. Perfect!

I always carry a spare plug, prop spring, throttle cable, fuel line, and a complete base plate with ignition. that 's it!

Good luck and fair tide!

Albert

Mick,

I did say they were rough and ready! my equation, for some reason had 1.34 X square root of LWL. I have to say I did find 4.5 a bit on the low side but also nearly 7 knots?!?!?! think the truth lies somewhere in between, I can see just over 5 knots in use so I reckon it to be around 6 ( would love to see 7 though!! )

As a matter of interest the required HP comes out at 7 HP if you take hull speed as 7 knots or 5HP for 6 knots.

As a further point of interest the Invader was originally sold with a 4HP outboard.....

The majority of texts I've seen on naval architecture quote 1.34x sq. root of waterline length as the proper figure for displacement hulls. Seems that 1.6 could be for hulls with a D/L ratio of less than 150.