Motor Yacht mini sail

[SouthernPride]

I am considering adding a mini sail to a 53' motor yacht. More curiosity than anything. I carry 600 gallons of diesel and don't feel like carrying a half a dozen 55 gallon of diesels on the foredeck.

Anybody have familiarity or advice about a project of this type.

Thanks

[markpierce]

A mini-sail will hardly get you anywhere. You are likely to have the wrong boat.

[ranger58sb]

Might be useful for "steadying" at slow speeds or at anchor, but... otherwise I'd guess it won't help you make headway all that much.

Where are you traveling that needs that much range?

I think most of the MY folks on trawlerforum.com just slow down when they need longer range. FWIW, that's what we do... and of course that reduces the fuel dock tariffs too...

We stayed aboard in Charleston over last winter; nice place...

-Chris

[gonesail]

seriously you need a thousand gallons of fuel onboard?

[storyinframes]

maybe get some inspiration from the new Nordhavn motorsailer. they have a tall mast though.

[TrentePieds]

Hmm... Your boat has a displacement of about 30 tons. It is driven by 1,300 horsepower. Supposing you could hang 400 sqft of canvas on 'er (which I doubt), what do you think the windspeed would have to be to push 'er straight downwind at, say, 10 knots, which I dare say, is the minimum your'd be satisfied with? If the wind blew that hard, could she survive at sea, her original design objective (coping with Cape Hatteras) notwithstanding?

Powerboats' hulls are shaped as they are because they rely on an untenable consumption of hydrocarbons to move them. Even slowly. Sailboats' hulls are shaped as they are in order that they may be moved at an acceptable speed, low though it may be, by whatever force is harvestable from the winds without the expenditure of hydrocarbons.

If your objective is to economize on hydrocarbons, and you will be content to move at sailboats' speeds, then dump the Hatteras, fine motor yacht though she be, and get yourself a decent sailboat. If living space is more important than almost every other selection criterion applied to sailing vessels, get a catamaran.

IMO, hanging rags on a Hatteras would be a fools' errand :-)!

TrentePieds

[SouthernPride]

Thank you for the input. Scratch that idea. Looking at Bahama's to St. Thomas with stop overs for fuel, rest, etc...Burns 30 gallons an hour at 11.5 knots. From what I have seen, read, and documented 11.5 knots on her is most efficient.

[Mikado]

Originally Posted by SouthernPride

Thank you for the input. Scratch that idea. Looking at Bahama's to St. Thomas with stop overs for fuel, rest, etc...Burns 30 gallons an hour at 11.5 knots. From what I have seen, read, and documented 11.5 knots on her is most efficient.

I had a 48' Marine Trader trawler with a 125 square ft steady sail. It definitely made the ride more comfortable but didn't help with fuel mileage. I used 4.5 gallons an hour at 8 knots with or without the sail.

30 gallons an hour to cruise at 11.5 knots in 53' motoryacht? That seems extreme to me.

[ranger58sb]

Originally Posted by SouthernPride

Thank you for the input. Scratch that idea. Looking at Bahama's to St. Thomas with stop overs for fuel, rest, etc...Burns 30 gallons an hour at 11.5 knots. From what I have seen, read, and documented 11.5 knots on her is most efficient.

30 GPH at 11-12 knots seems like a lot, to me. What RPMs is that?

I know of a boat like our model, including our same engines I think, that made St. Thomas without extra fuel bags or barrels etc. Can't remember details about their fuel stops, though... but they were even running on plane for each leg.

I'd guess you could reduce fuel burn a lot by slowing down to 8-9 knots, somewhere in there. That's just using 53 as your OAL, so you could probably do that calculation better with the real OAL.

Stabilized? If not, I know we have to pick decent weather windows and sea states to just putter along comfortably...

I think there are a couple 53 owners on trawlerforum, and they could maybe kibitz.

-Chris

[Paul Howard]

twenty years ago I worked for a boat building company and we had a former sailboater purchasing a 55ft. trawler yacht who wanted a sail on it. It was the only one we did, but instead of the usual sloped back mast with antennas, etc. we designed a rig with about 300sq.ft. of sail that was cut flat and had a wishbone boom so it was self-vanging (the boom did not lift when the pressure was on the sail and kept the sail shape correct). Something like you see on the Nonsuch catboats (sailboats). The boat displaced about 75ton, with 300hp engine and cruised at 8.5knots. They sailed u.s. coast, caribbean, to europe, etc. and said the sail made the boat much steadier and also gave about 0.5knot boost to the speed at the same rpm.

[Simi 60]

Originally Posted by SouthernPride

...Burns 30 gallons an hour at 11.5 knots. From what I have seen, read, and documented 11.5 knots on her is most efficient.

Frightening stuff

And here was me worrying about a bit under 4 us gallons/ hour @ 8.5knots.

[Simi 60]

Originally Posted by gonesail

seriously you need a thousand gallons of fuel onboard?

That's not much
We carry double that
If i bring online the "spare" tanks that could add another 580 us gallons.

That would then give us an effective range of 5500 nm

[TrentePieds]

Specific fuel consumption for a diesel in good nick is fairy linear over the useful range of "throttle" settings. RPM is governed by the quantity of fuel injected (and optimally burned).

A bench mark in practical terms is that to produce a continuous 300 HP, you need to burn 17 gallons of fuel per hour. At "half throttle" a standard Hatteras 53, having 1,300HP installed, would generate 600 HP or so, 300 from each engine, and the anticipated consumption would therefore be 34 gallons, which is close enuff to SouthernPride's 30 gall/hr.

At full "throttle the boat should go about 18knots. 11 or 12 knots at half throttle is therefore also quite reasonable.

TrentePieds

[Calif.Ted]

Well, I took a picture of this boat because some people didn't believe me without evidence.
It's an '81 Roughwater 36 by Ed Monk Jr., 1 of 4 built with mast and sails "for extended cruising in the PNW".

[GrowleyMonster]

What they said. Your Hatt is the wrong boat for a mast and sails, if the objective is propulsion assistance. A steadying sail is another thing altogether, and might be sort of useful. A steadying sail is best deployed well aft. A sail plan for moving the boat would have it's center of effort somewhere very near to the boat's center of lateral resistance. This would still work poorly. No keel. You would not be able to go to windward. It would even reach poorly. Running (wind dead astern or nearly so) is a slightly different matter and I could see you sailing a 53' Hatt at a couple kts in a decent breeze. It would roll like a drunken pig, though. Fuel savings would hardly be worth the work of managing the rig, or purchasing/installing it. And it would not be a very mini sail, no. And you would need a compression post between mast step and keel, as well as chain plates in appropriate places.



If you want to sail, or save fuel, get yourself a sailboat or a motorsailer. You could go days without burning any fuel at all, and have essentially limitless range. You might be surprised to find that you like it.