Hi Donald,
Here's an excerpt from a post in this group from January this year that discusses your point fairly well.
"Referring to other posts, it takes very little power to move large floating objects at slow speed. Old school fitness guru, Jack LaLanne used to tow various things on his birthdays to show that he was still in shape. Here's a few of those events:
1957 (age 43): swam the Golden Gate channel while towing a 2,500-pound (1,100 kg; 180 st) cabin cruiser. The swift ocean currents turned this one-mile (1.6 km) swim into a swimming distance of 6.5 miles (10.5 km)
1974 (age 60): For the second time, he swam from Alcatraz Island to Fisherman's Wharf. Again, he was handcuffed, but this time he was also shackled and towed a 1,000-pound (450 kg; 71 st) boat. At least that's according to his website. However, according to an account of this event published the day after it occurred in the Los Angeles Times, written by Philip Hager, a Times staff writer, LaLanne was neither handcuffed nor shackled if each of those terms has the unconventional meaning of "tightly binding the wrists or ankles together with a pair of metal fasteners" although that's not how handcuffs or shackles work. Hager says that LaLanne "had his hands and feet bound with cords that allowed minimal freedom". But "minimal" clearly did not mean "no" freedom, since elsewhere in the article Hager describes LaLanne's method of propulsion through the water as "half-breast-stroke, half-dog paddle" which is how you swim with your hands tied.
1976 (age 62): To commemorate the "Spirit of '76", United States Bicentennial, he swam one mile (1.6 km) in Long Beach Harbor. He was handcuffed and shackled, and he towed 13 boats (representing the 13 original colonies) containing 76 people.
1979 (age 65): towed 65 boats in Lake Ashinoko, near Tokyo, Japan. He was handcuffed and shackled, and the boats were filled with 6,500 pounds (2,900 kg; 460 st) of Louisiana Pacific wood pulp.
1980 (age 66): towed 10 boats in North Miami, Florida. The boats carried 77 people, and he towed them for over one mile (1.6 km) in less than one hour.
1984 (age 70): handcuffed, shackled, and fighting strong winds and currents, towed 70 rowboats, one with several guests, from the Queen's Way Bridge in the Long Beach Harbor to the Queen Mary, 1 mile.
Obviously, his maximum power output in this configuration is pretty low. But for each of these stunts, while he wasn't fast, he did have the endurance to complete the swim (and a chase crew in case he got too tired).
This proves that small motors can move large boats in calm conditions, but for basic marine safety, we should have enough power to manueuver in adverse (not extreme) conditions. That's where this group's guideline of 1kW of power for each ton of displacement comes from. This will typically provide 85-95% of hull speed in calm conditions and seems to give reasonable power in less than ideal conditions."
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, donald bland <dlblandjr@...> wrote:
>
> yep, in reality it does NOT take an elephant to move a 10 ton sailboat. 30 years
> ago , before my wife was my wife , we were swimming , of an island in the gulf
> of mexico or the caribian , somewhere, we had the "gypsy " my steel hull 10
> metre, (33foot ) a yacht registered a 20 tons , although I'm not sure she
> actually withed anywhere near that, the registration is on displacement of sea ,
> not on gross wight. anyway , Lupita,(5' tall 90 lbs soakin wet with a pitcher of
> beer in both hands , so a tiny chick, just pushed my boat and it moved some 10
> feet , she was calling herself "superwoman" for a long time. but
>
>
> yep, they move pretty easily on water, now planing hulls , they eat some serious
> power to "get up" but a sailboat , moves pretty easily at her hull speed. I have
> been sailing since 1965, so I have a limited amount of experience to share on
> the subject.
> Don Bland
>
>
>
>
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