turning a sailboat into a motorsailor

I've been looking for a sailboat with a pilothouse but there are so few of them that my choices are very limited. I was wondering what the issues would be in adding a pilothouse to a regular sailboat. I've thought of three possible scenarios:

(1) Get a center-cockpit sailboat and just add a hard cover over the cockpit.

(2) Get a rear-cockpit sailboat, cut a hole in the top of the cabin and build a pilothouse to replace it.

(3) Get a rear-cockpit sailboat with a cabin that is a lot higher than the deck at the bow, cut out windows in the front of the cabin and install controls there.

I wouldn't just take out the circular saw and start cutting; I would hire someone who knows what he is doing to design the change. But before that I have to buy the boat and before that I'd like to get a feel for what is possible.

I assume that (1) wouldn't have much effect on safety, especially if I left in the regular hatch covers, but it leaves me without the outdoor cockpit for good-weather sailing. I guess I could build a solid cover that can be removed in sections, but I've had the T-roof off of my Trans Am about five times in ten years. I'm not sure the boat would be any different.

Are the other two ideas just too crazy to consider? Can any of these mods be done by someone who has never worked with fiberglass before? What am I looking at in time and materials? Would I be better off hiring pros to do it, and how much is that likely to cost? If I had to raise the boom a foot or two for clearance, what would be the issues?

And then there is the speed. If I did buy a regular sailboat and added a cockpit, I'd probably want to make it go faster too. I could buy one with an old engine that needs to be replaced and just add a bigger engine. Is that going to work, or is the bigger engine just going to use a lot more fuel without speeding the boat up very much?

I'd much appreciate any knowledgeable advice.

 

It's a difficult question. The boat doesn't exist yet. However, if it was me, I'd look for an aft cockpit boat if for no better reason than they are far more prolific out there. You might then pick out the boat you want and narrow your search.
Any boat of reasonable size can be modified, though I'd look for a boat with a big cockpit and a smaller (shorter) cabin to start. This will allow the wheelhouse to sit about where a dodger would, but it would extend further aft than a dodger. In a sense, it would be like a hard extended enclosed dodger. It would help if the cockpit could be smaller, maybe 5 ft long. By not having to gut the aft end of the cabin, you'll save thousands.
Don't reinvent the wheel. Stay solid and conservative. Leave the newfangled designs to the really experienced designers/sailors.
Finally, the category appears to be "MacGregor 26 not good?". I wouldn't think a MacGregor would be a good candidate for such a modification. Too light a boat. The weight would sink it I think, or the windage would be too much.

 

To quote PAR to some extent...sorry..... this isn't the exact quote....but here it is...

" Is their money oozing from your rear-end orifice?


..If so..then get a designer/builder and tell them what you want..they'll figure out the rest. Otherwise I'd try real hard to find what your after...maybe look in Canada/Vancouver,Maritimes and in the U.S. in the Northeast, the Great lakes and Washington/Oregon. If you still can't find a cheap one then buy a cheap Pearson 30 a Hunter 27 or something..try it like it is for awhile..then if you still want a motorsailer mid-cockpit..then you've had a awhile to study and practice with materials/fiberglass techniques and draw up the plans so your D.I.Y.custom- remake goes well...

 

Dave, its not a silly idea at all,there are way to few of this type of boat available out there and sometimes when what you want just is not available you have to get creative.It would be helpful to know what size boat you are looking fo so we can help with some suggestions.An example of the factory doing just what you are talking is the Islander 37 motorsailor which has the same hull as the sailboat.As far as getting more speed it usually requires a different hull form aft and as you say more horsepower will not necessarily pay dividends.
Steve.

 

As long as your desire for more speed isn't for a lot more speed, and you'll be content with maintaining hull speed even in a bit of a headwind, a typical displacement cruising sailboat hull may be just fine. You may be able to gain a little efficiency from the existing engine at the expense of its speed under sail only simply by replacing its prop; most sailing props are designed to minimze drag while sailing rather than to produce the greatest thrust under power.

 

Thanks for the info, everyone. To answer a few of your questions:

1. If money were no object then I would just buy the kind of boat I want instead of trying to find a way to get it on the cheap.

2. My criteria are probably pretty typical. In rough order of importance:
(a) liveable. I want it big enough for two people to live comfortably for an extended period.
(b) fast. I want to use it for travel and a faster boat gives a greater practical range. I don't think I would seriously consider a boat that couldn't cruise at 8 knots or so. I'd rather have it a lot faster.
(c) a pilothouse
(d) seaworthy (the low position of this in the list indicates my intended use for the boat: bay sailing and fair-weather coastal cruising.)
(e) a good-sized cockpit

3. I'm thinking of a boat in the 35-50 foot range. I know that's a big range but I have conflicting interests. Smaller is easier to handle and cheaper to dock. Bigger goes faster. So, I guess I'll take the best buy I can find in that range, with a slight preference for bigger.

No bigger than 50 feet. I was about to make an offer on a 54' center-cockpit ferro-cement ketch. It was a tremendous buy. But just before I made the offer, I called around to about ten marinas in the area and couldn't get a slip for it except for one outrageously-expensive end tie.

5. No wood or steel hulls. Several marinas around here won't take wood boats and I want low maintenance.

6. It has to be cheap.

There are some tremendous deals available right now so I've been shopping. But there aren't a lot of motorsailers and pilothouse sailboats. My price constraint leaves out catamarans which would otherwise be ideal. There are some older trimarans that I could afford, but the one I looked at had these huge support beams through the living space. The passage from the main room to the head was only about four feet high and my back could not handle that in the long term (are all sailing tris like that?)

Anyway, I really appreciate the advice so far.

 

(a) liveable. I want it big enough for two people to live comfortably for an extended period.
(b) fast. I want to use it for travel and a faster boat gives a greater practical range. I don't think I would seriously consider a boat that couldn't cruise at 8 knots or so. I'd rather have it a lot faster.

If ypu need to travel CHEAP, the speed will be the sq rt of the lwl times a max of 1.15.

So that 50 ft boat if 49 on the lwl would barely make 8K.

So you need a MUCH bigger boat if you "need" 8K in most conditions.

Room to be tossed from hull side to hul side is not a help for a moving boat , but its OK in port for houseboat folks.

House boat is not derogative , remember some fine Trumphy 72 ft "houseboats " are still eye candy .houseboats .

It has to be cheap.


NO CHANCE , with the list of desirements you expect.

"(c) a pilothouse
(d) seaworthy (the low position of this in the list indicates my intended use for the boat: bay sailing and fair-weather coastal cruising.)"

Sounds like one of the old Taiwan Tubs 45-50ft or so "trawler" would fit the requirements better than a sail boat with 1/3 the room.

Cheap to buy , cheap to repair , although on most replacing the deck and cabin will be needed.But that's mostly low skill GRP work , easy to learn in a couple of days as grunt helper.

FF

 

The design you want is available currently and doable as a retro fit, though this would likely be more costly then finding a motorsailor of the configuration you desire.

It's very difficult to find a builder that also happens to have the design skills to do what you're asking (unless a very big yard). Typically, a builder would have a designer they'd use, possibly locally to insure things wouldn't "fall off" on launch day.

The basic problem is you'll be making alterations to the deck cap, liner, furniture and likely several structural elements. This assumes you'll not have to move major systems, just modify them to suit.

You can have your aft cockpit (small), pilothouse, sailboat, but my first suggestion is contact a designer and work out some of the details.

Most of the things on your list are attainable, some aren't, others just require more understanding of the issues and compromises necessary, but a successful venture will require professional help.

 

Thanks for the encouragement, Par. Thanks for killing my dreams, Fred.

Just kidding

Fred, I'm aware that I'm going to have to make compromises. That's why I gave the list in order of importance. And as you suggest, I think one compromise that I'll have to make is giving up sailing (I should have put that on on my list as well, but it would be near the bottom).

But that doesn't solve all of my problems. I've had a hell of a time trying to find out the speed and fuel consumption of power boats. Less than half of them list a cruising speed and almost none list fuel consumption. But as near as I can tell, there are two classes of boats in the size range I want: those that cruise at 8 knots and those that cruise at 6gph. I'd like to find a nice compromise between those extremes but information is so hard to come by that I probably wouldn't know it if I saw the perfect boat.

As to houseboats, I assume that some boats are designed strictly for inland waters. I don't know how to recognize those boats other than that they are called houseboats. If there are houseboats that I could take out into the ocean in good weather then I would definitely consider them. But, again, how can I tell. Googling boat models has been almost entirely useless. Occasionally I get lucky and find an offhand comment (often on this forum ) but most of the time I get nothin'.

Also, I think I could probably go down to 30 feet or so in a power boat and still have enough room to live --if it were laid out right.

 

Since it doesn't need to be a motorsailer but you would like to hit 8 knots lets back up the design curve a little bit.

How many gallons of diesel are you willing to burn in an hour when cruising at 8 knots?

 

Tolly, if I'm going to give up sailing, I'm going to need a lot more than 8 knots to compensate. If the traveling part is less fun, I want to spend less time doing it .

I went back to the map of San Francisco Bay and did some estimations on distances. It has made me rethink the costs somewhat. If I could get 2 nm per gallon even the long trips would cost no more than $200 in fuel. That works out to 8 gph at 16 knots. Does that seem reasonable in the size range of 33' to 40'?

And how do I shop for a used power boat with those performance characteristics without wasting a lot of time on boats that don't qualify? I'm mostly using yachtworld.com and they often don't even list the cruising speed.

 

www.yachtsurvey.com/boatreviews/indexboatreview.htm

Spend a few days reading the reviews of existing boats.

Get The Nature of Boats D Gerr out of the library or spring for a used copy.

At displacement speeds , the traveling is very enjoyable and frequently far more comfortable than bouncing along on top of the water like a B Whaler.A set of $6000 Stidd seats and extra denture glue is sometimes required.

I would suggest a ride in both in modest weather to see which style suits YOU.

"That works out to 8 gph at 16 knots. Does that seem reasonable in the size range of 33' to 40'?"

Very doubtful 1 nm / gal is more realistic at 16K in a 40 ft boat.

However a proper 40 ft DISPLACEMENT boat may well do 7K at 2 gph,
and NO just running slow in the speedboat does not give the economy of a proper displacement design.

For big distances ONLY the displacement boat can carry the fuel, most plaining fish killers or "motor yachts" carry 3-400 miles of fuel 20 gph takes a lot of fuel.

For a modern nice looking displacement house boat (designed for NOT crossing an ocean) look at a Pilgrim 40.

www.pilgrim4sale.com/3.html

These can run the coast , many have crossed the Gulf Stream to the Bahamas, by waiting for a weather window.



FF

 

I'm a bit of a nerd about engine monitoring. The first and almost best thing I got for my boat was a fuel flow meter. I learned more in a 1/2 hour than I would have in a decade with a dipstick about my fuel burns. I average about 1.2 to 1.3 knot/gal throughout a fairly wide envelope. This is in a much smaller (28') boat burning gasoline.

On a 58' boat I used to fish on the skipper claimed about 10 gallons/ hour @ 10 knots. That was a displacement hull being pushed faster than optimum, not a recipe for top milage.

You are in an awkward part of the performance envelope. If you can live with less speed your first idea will work splendidly, if you need as much speed as indicated for a "powerboat" it may need to be smaller than you want. As an aside my boat has accomadations (sic) as useful as the 35' sailboats of my friends. Burning diesel instead of gas I could probably do better than 2knot/gal at speeds of 8 to 12 or 14 knots.

Frisco is a great place to sail so I can see your desire for a sailboat. Fred's suggestion about Gerr's book is a good one. It will give you you a pretty good rough picture about theoretical fuel burns and performance. His view's on fuel burns etc. are also worth paying attention to. Good luck, so many boats so little time (and money).

 

Now that you are considering power-only, you might want to look at lobsterboat type hulls. They have a fine entry and relatively flat run from midship to transom, and so behave reasonably well in the transition zone between displacement speeds (less than 8 knots in your size range) and fully planing. They are designed for offshore work, and so ought to suit your criteria.

 

Dave Gudeman,

There is a fiberglass Sailboat Hull near Boston, Mass that has been sitting for some years but has nice lines, looks to be in very good condition and looks to be a large and roomy inside hull. She was not ever completed and is about 35'. I think the marina would sell her for $1,000. I would love to install BLDC electric propulsion in that boat. What a wonderful vessel she would be.

JCR