if you put a sailmast with sails on a powerboat what would happen?

[sdowney717]

This would be on a semi displacement or full displacement power boat.
Would it roll over when the wind filled the sails?
Or would the large twin iron engines prevent that.
What if the power boat had a large long center keel, but not a weighted sail boat keel?

[maxingout]

I knew a person who had a large trawler that was rigged so he could run a square sail. He was moving the trawler from Australia to the USA, and he wanted to be able to turn around and run downwind if he lost mechanical propulsion. He simply put up a mast with a single yard on which to spread the square sail.

[bobconnie]

Lots of power boats have at least steadying sails from thier mast and swing boom, and at times these sails can add a little drive to the boat. Not that it will ever really add a great deal of extra mileage LOL but they can help and do steady the boat down if the wind is right ! Just my 2 cents

[Ike]

What bobconnie said. Trawlers have often had a steadying sail. Putting a mast and sails on a power boat would work sort of. No it wouldn't roll over, unless you put on a reall tall mast and sail. The boat would move, but would have considerable side slip, and wouldn't go up wind worth a damn. Down wind it would help some. All this depends also on the size and configuration of the sail. But it really probably would not be worth the effort and would add a lot of weight topside. It would be horribly inefficient.

If you want to do that get a motorsailer. A motorsailer is a compromise between a powerboat and a sailboat. They have a good size suit of sails, sail reasonably well, and move well under power. The drawback, they do neither as well as a power boat or a sailboat. As I said, they are a compromise.

[Jim Cate]

Originally Posted by sdowney717

if you put a sailmast with sails on a powerboat what would happen?

My guess is that all the powerboat guys would laugh at you, whilst all the sailboat guys would... laugh at you too!!!

Seriously, as others have said, you might get some help with the apparent wind at >130 degrees or so, but unless you are planning long tradewind passages it would not likely be economically useful.

Properly designed sail assisted motor yachts do exist, but as an add on it seems unlikely to be a success.

Cheers,

Jim

[MarkSF]

Originally Posted by Jim Cate

My guess is that all the powerboat guys would laugh at you, whilst all the sailboat guys would... laugh at you too!!!

You just described MacGregor ownership! (with sincerest apologies to any owners on this forum, just a joke)

[david samuelson]

if it is downwind help you need just fly a BIG kite (no, not a spinnaker, a kite) It'll drag you along and can't roll you over! !

[Dockhead]

Originally Posted by david samuelson

if it is downwind help you need just fly a BIG kite (no, not a spinnaker, a kite) It'll drag you along and can't roll you over! !

Oh, you should look at some spinnaker broach videos on Youtube before you say that!

Surely it depends on what kind of stability the trawler has. Some of them have pretty deep keels. I don't know why you couldn't get quite a lot of drive out of add-on sails, especially downwind in a decent blow, and save a ton of fuel if the wind is right.

Remember that deep, ballasted keels are a relatively recent invention. Sailing ships for centuries didn't have them -- they looked a lot like modern trawlers. They had lower masts in proportion to their other dimensions, and spread their sail area over a longer length. I don't know why you couldn't do that on a trawler and get perfectly decent performance downwind or on a reach.

On the other hand, you could just buy a Nauticat or some other motorsailer and get the same effect, only with the benefit of having everything designed for that in the first place.

[drifting off topic a little] People disdain motorsailers as bad sailboats combined with bad motorboats, but I don't see why this should be the case. Efficient sailboat design is needed for a boat to do well in only two situations: (a) beating to windward; and (b) in light winds. In all other situations, you don't need tall masts, high aspect ratios, deep keel, etc. Downwind the sails are producing nothing but drag -- you can put up any old rag, anyhow, and its performance is determined almost purely by area.

Since most cruisers don't go to windward at all or almost not at all, and don't sail in light wind, but rather motor in such circumstances, I think most of us are operating like motorsailers anyway. Certainly that described my last boat, which had such poor performance under sail that it was completely useless to try to make any miles to windward. So why not shorten the masts, have more of them, reduce the sail area, and improve the motoring performance of a boat, so that it works well during the inevitable 50% or 60% or even more miles which are made under motor? And besides that, have a nice heated pilothouse which makes it pleasant to make miles in bad weather? Seems perfectly reasonable to me.

In fact in the UK, where my boat is based, a surprisingly large proportion of yachts with sails are motorsailers -- Nauticats, Fishers, Colvics, and many others.

[Uncle Bob]

Originally Posted by Dockhead

Oh, you should look at some spinnaker broach videos on Youtube before you say that!

Surely it depends on what kind of stability the trawler has. Some of them have pretty deep keels. I don't know why you couldn't get quite a lot of drive out of add-on sails, especially downwind in a decent blow, and save a ton of fuel if the wind is right.

Remember that deep, ballasted keels are a relatively recent invention. Sailing ships for centuries didn't have them -- they looked a lot like modern trawlers. They had lower masts in proportion to their other dimensions, and spread their sail area over a longer length. I don't know why you couldn't do that on a trawler and get perfectly decent performance downwind or on a reach.

On the other hand, you could just buy a Nauticat or some other motorsailer and get the same effect, only with the benefit of having everything designed for that in the first place.

[drifting off topic a little] People disdain motorsailers as bad sailboats combined with bad motorboats, but I don't see why this should be the case. Efficient sailboat design is needed for a boat to do well in only two situations: (a) beating to windward; and (b) in light winds. In all other situations, you don't need tall masts, high aspect ratios, deep keel, etc. Downwind the sails are producing nothing but drag -- you can put up any old rag, anyhow, and its performance is determined almost purely by area.

Since most cruisers don't go to windward at all or almost not at all, and don't sail in light wind, but rather motor in such circumstances, I think most of us are operating like motorsailers anyway. Certainly that described my last boat, which had such poor performance under sail that it was completely useless to try to make any miles to windward. So why not shorten the masts, have more of them, reduce the sail area, and improve the motoring performance of a boat, so that it works well during the inevitable 50% or 60% or even more miles which are made under motor? And besides that, have a nice heated pilothouse which makes it pleasant to make miles in bad weather? Seems perfectly reasonable to me.

In fact in the UK, where my boat is based, a surprisingly large proportion of yachts with sails are motorsailers -- Nauticats, Fishers, Colvics, and many others.

As a Fisher owner I am obviously biased but I have had several keen sailers onboard who have commented on the unexpected sailing performance. For example "This thing sails better than I expected" and " 5.2 knots out of 9 knots wind speed, can't complain about that"

[Blue Stocking]

A little off the subject, but--before containerization of cargo, Royal Mail used to run some good size freighters, 15000 tons IIRC, on the England, Bermuda, Caribbean, and return run.
On one return to Bermuda, prevailing SW wind, the Orcoma lost her drive engine.
The English Captain, from the old school, wung out the derricks, hauled out huge hatch cover tarps, and made way towards us until the tug met up with him.
Sooo--it can be done.

[sdowney717]

What interested me was seeing this picture.
That boat looks very similar to my 37 egg harbor sedan cruiser from 1970 which is a wooden boat I rebuilt completely, framing etc...


I have an almost full length keel which is about 2.5 feet in height at the stern end and runs from stem to about where the prop struts are bolted on the hull.

I could imagine a mast up where the front cabin starts about 6 feet back from the stem. Or stepped right in front of the sedan windows as in the photo. It would need to be stepped on the cabin roof or it would block too much interior access. So I dont know if that is doable.
Anyway If it would not simply roll over thrn who knows what I might do someday with this. I was talking with another boat owner who suggested the boat would tip right over on its side since a sail boat has a heavy keel, so was curious what others thought.

You could bolt a lead keel plate to the bottom of the keel.
But why bother if you dont have to do that?
Right now boat draws 3.5 feet and weight 17,000 pounds. Carved into the wood structure someone wrote "15 tons net" but I know the boat does not weigh 30,000 lbs.

Any more thoughts besides it being a dum idea?

[sdowney717]

Originally Posted by Ike

Putting a mast and sails on a power boat would work sort of. No it wouldn't roll over, unless you put on a reall tall mast and sail. The boat would move, but would have considerable side slip, and wouldn't go up wind worth a damn. Down wind it would help some.

How tall would be too tall?
and
with the current keel running 3/4 of the boat length would it slip sideways?

some photos of bottom during repairs when I coated with permaflex.
back of keel which looks about 2.5 feet depth.

looking forward to stem

This hull tends to plunge forward deeper toward the stem sort of like a gold fish. It is a round chine and very smooth riding boat.

[Blue Stocking]

With that long pulpit and crowsnest, she looks like a swordfiherman. Nice though.

[Blue Stocking]

The info you need to get a better idea of stability is all on the web.
Things like center orf gravity, center of effort, center of lateral risistance, righting moments, lever forces, are all there.
I think it would be an interesting project.
Look up William Hand m/sailers, and the Virginia Reel boats.
Beauties all, IMHO.

[sdowney717]

I always liked motor sailors

Here is a pleasant looking one and large and roomy.
What I tend to not like about regular sailboat is they feel really tight for space.
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