I don't know that I'd go to the effort to "Cut down" a rig as someone suggested in one of the other responses - seems like it should be EASY to reduce sail area if desired without having to change the mast or rigging at all.
Removing the keel could help in "powered" mode, but does risk side effects. And then you have eliminated the sailing opportunity.
I do have to admit that I "garaged" the boom on my Catalina 22 in favor of installing a tall enough bimini to be able to stand under. My C-22 is now, I guess, an electric "motor-sailor".
All of my measurements so far on speed / power / batteries were done with NO sail at all.
However - I've read, and verified, that when sailing, using a SMALL amount of power will quickly add .5 to 1mph to your sailing speed with very low draw on he battery.
At slow sailing speeds - especially on days with lighter winds... Motorsailing with the electric could easily boost your speed 20-25%, with tremendous range.
You'll still never beat hull speed by much without using a LOT of power. But it might be interesting to look more at the combination of electric and sail.
With GAS / DIESEL engines, once you start the engine, there doesn't seem to be much point in motor-sailing. You already have the noise, the stink, and the gas consumption. Going from "cruising speed" to just "sail assist" would save a little bit of gas, but probably not enough to bother with.
With an electric, however, it's still quiet, doesn't smell, and you're only burning as much power as you're using. ESPECIALLY for full inboard configurations, just a few watts will turn the prop fast enough that it at least is no longer an underwater brake.
It would be interesting to see this summer if using the electric and a jib only configuration could get me more than 20% speed increase over jib alone, and still have a huge roaming range. The only problem I have with this is that the winds on my lake (dammed up part of a river) are so flaky that it's almost impossible to measure what is contributed by the sail and what is contributed by the engine.
John
From: "cirejay@hotmail.com [electricboats]" <electricboats@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Friday, May 15, 2015 7:01 AM
Subject: Re: [Electric Boats] Daydreaming about the next project: An electric day cruiser...
The fact is, many do use old sailboats to go electric. And yes, the true displacements hulls are a great place to start.
I'm not sure how many have cut down an older rig to, in essence, create a motorsailer that is more on the motor side of the equation. Why not just leave the sail rig as it is and use it as is?.
As for needing to be on the water/planning to exceed hull speed, I don't believe that's entirely accurate. The need for huge amounts of power to exceed hull speed is certainly right on, no matter what the source of power is.
Along with Meander, a Seawind II ketch, I recent acquired a Gulfstar 36 trawler that has the advantage of being based on their motorsailer hull and, as such, is a true displacement design.
It is currently ridiculously overpowered with twin 85hp Perkins diesels - she'll do 8.2 knots on one engine while dragging the other 17", 3 blade prop. My goal is to pull one engine and replace it with a 12.kw motor as a 'proof of concept' of sorts. If that works as intended, I will pull the other engine, add another motor, more solar panels and generator.
Unfortunately, that project is on hold as I'm scheduled for back surgery the end of July. It's something to look forward to though.
Wishing you luck with your project and looking forward to hearing how it turns out.
eric SV Meander
---In electricboats@yahoogroups.com, <artzboyz@...> wrote :
any boat IN the water is limited by hull speed. even approaching hull speed increases power usage exponentially. to exceed hull speed, the boat needs to be ON the water. if you can make the weight per square inch ratio low enough, a flat sheet of plywood may be the best planing boat. add weight and you're back to displacement speed and power use.
i'm surprised more electric boat aficionados don't use old sailboats. some sailboats are lightweight, have removable weighted keels and narrow efficient beams. keep some of the sails and you have an alternate method of power if you run out of battery power.
i have such a boat, an old venture 21, that i'm considering adapting to electric power. if i cut down the mast, i'll still have some sail power if needed but in a more manageable configuration. if sea trials warrant, the keel can be reduced too. it's 400 lbs now with a bulb of lead on the end. the boat, trailer, sails and 9.9 outboard cost me $900. the beam is 6'10". pretty inexpensive way to build what i think could be a fine design for conversion to electric power.
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Posted by: oak <oak_box@yahoo.com>
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