ESPcat – Why Go to the GYM?

For all you 76 year olds out there, rather than go to the gym, I suggest you antifoul a boat.

Above is the after photo.  There is no before image because the catamaran hulls were in such a terrible, neglected state that a photo is just too embarrassing.  The reason I suggest you could avoid going to gym by doing this job is that it is a complete ball buster.

Much of the work must be done by crawling around underneath between the hull and the haul-out cradle, while in a crouched position.   There is endless water blasting, scraping sanding and groaning involved.  But when you finish, the result is a sight to behold.

Anyone considering turning a catamaran sailboat into a power boat (particularly a solar powered boat). Should consider the above pictures.  I may have made many mistakes with this project but choosing the hulls was definitely not a mistake.  Just look at those graceful lines.  And bear in mind that the waterline length is 8.5 m while the hull waterline beam is 0.7 m.   That makes the ratio of waterline length to beam equal to 12.  Once that ratio gets to 12, the hull is so narrow that the bow wave is non-existent.  Without a bow wave, there is no longer such a thing as hull speed limitation.  Hull speed occurs when a displacement hull travels fast enough that the stern begins to fall into the trough of the bow wave.  Ordinarily an 8.5 meter displacement boat has a hull speed of 7.1 knots.  Try to go faster and the stern just drops further and ends up with very little speed increase. 

When Borderline was a sailboat, she was clocked at 28 knots!  Boat speed on Borderline is limited only by hull friction and that is why I absolutely must do a better job of keeping her hull clean. So all my sanding and painting and grunting, should allow Borderline to reach 8 knots with her new, tiny twin 9.9 hp engines.  Incidentally, the twin, 10 kw electric motors that will eventually power Borderline, will also produce 9.9 hp. I can’t wait to see if we can actually get the predicted 8 knots of boat speed the way God intended. 

And just to make the antifouling job even more difficult, I also replaced the unmatched, 8 hp engines with much newer, 9.9 hp, 4 stroke, High Thrust Yamaha engines.  These High Thrust babies have 11 ¾ ” diameter, 5 ¾ ” pitch propellers and a 2.92:1 gear ratio.  High Thrust engines are perfect for pushing a boat that weights around 2,000 kg.  Fingers crossed. 

I did my 44 push-ups then went for my 4 km Sunday run today.  I felt quite fit for an old fart.  It must be all that antofouling.      


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