69723Re: Fast Motorsailor
- Jul 16, 2013Peter
You seem to be referring to the FMS on the squareboats page http://www.ace.net.au/schooner/fms.htm I somehow don't think the original 70HP let alone the later 140HP would have amused PCB much.
15 kts is incredibly fast for a 23' sailboat and I would happily settle for that (or less). I assume you'd get hull speed (or perhaps more under some conditions) with 10HP or so. Any idea how to guess speeds with given HP for this type of hull appreciated.
One would be lucky to get Seabird 86 up above 7kts under any conditions and accommodations, trailering and construction cost (with ballast) are in a different league.
With the distances involved where I sail (central Chile) and the prevailing conditions (a lot of wind from a pretty constant direction or none at all) the abilities of the FMS seem great to me.
If it comes to exploring the archipelagoes and tidal areas in the South of Chile, the ability to dry out flat and motor the narrow/shallow channels is a great plus.
My problem with Bolger is that I like too much of his work. Seems like I'll be buying another set of plans.
--- In firstname.lastname@example.org, "Peter" <pvanderwaart@...> wrote:
> > Looking at the line drawings does show it will be a
> > better motor boat than a sailboat. Off wind it should
> > be fine under sail. A chart I looked at suggested
> > that guessing a weight if 2500lb ,
> > a 35 hp motor should get it up at about 15 knots.
> If you think about what a fast monohull sailboat looks like (heavy keel, tall mast), you see that the FMS is something different. It was meant to be able to use the rig downwind for the fun of it, or to save fuel. I'm sure it will sail upwind, but it doesn't have the rig or the power to carry sail to be fast hard on the wind.
> I think the 15KT on 30hp estimate is pretty good. If I remember correctly, one guy who built the boat but not the rig was dissatisfied with the performance with mid-teen speeds under power with 30HP and traded up to 70 HP. That got him to the 25KT range.
> PCB was a very good powerboat designer and he described the trade-offs of high and low power in several places. He liked low-powered boats for their quiet and economy, but he noted that once you want more than sailboat speed, you get a hull better suited for high-speed than low.
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