Converting sailboat to powerboat

[KnotYet]

"I don't recommend it to anyone."

The thing that I found the biggest caution was that they dumped over
$80k(!) of 1990 dollars into this long, difficult project and still only had
a fairly marginal cruiser.

 

[Jeff F]

The thing that I found the biggest caution was that they dumped over
$80k(!) of 1990 dollars into this long, difficult project and still only had
a fairly marginal cruiser.

That's not a lot of money to successfully pursue a dream. Haven't followed the link.

I dunno. My boat is a work in progress, imperfect and I have $100k in it. When I'm done with it in 20 years someone can buy it for $50k and do what they want with it. So what? I'm having fun.

 

[Nomad Willy]

I’ve always thought the good road to a conversion is finding the right hull design. It’s my opinion that the conversion hull best have full ends. Something almost impossible to find. Sailboats are designed mostly to run well below hull speed. Most trawler men will be expecting to cruise at hull speed. That’s pushing most sailboat hulls. Sailboat hulls are usually fine at the ends and fat in the middle. A recipe for rolling w/o a mast and big time pitching. Most of these problems will be solved w a full ended sailboat hull. The only one I know of that has full ends is a 27’ Albin w the rudder ahead of the prop. But if you find the right hull a very good trawler can probably be made. But there’s other problems w the idea like most sailboats old enough to be cheap have a short WLL. And if you find a NA to help he probably hasn’t ever done a conversion. Or thought about it. Or did it w the wrong hull and has horrible things to say about conversions.

 

[Jeff F]

Take a look at the boat I referenced earlier. It's a Pearson Countess, a John Alden designed motor sailor.

100 HP and something like 9 knots max cruise. Pretty sweet

 

[Hippocampus]

I'm in SW Florida with wrecked boats a plenty here.

There are a number of sailboats that need their mast, rigging, and sails replaced, but the rest of the boat is fine.

Would it work to just forget the sails and use it as a cruising powerboat?

What would be the downside?

The downsides have been well documented. Extremely uncomfortable boat except in very protected waters. Uncomfortable at anchor and underway. Unsafe in even moderate conditions. Possibility uninsurable so not allowed access to many if not most marinas. Much more expensive cost of ownership as any investments in time o money will not be recovered when sold.
Much has been made of prior conversions. A critical look at those conversions that have had a modicum of success shows they started with a fairly old school generic hull initially designed to allow function as pure power or sail. In the 1960-1970s when series grp construction took off the differences between power and sail hulls was much less than at present. High aspect bulbed fin keels were not done but rather low aspect full keels were common. Motorboats of that time be they Sebrights , commuters, wherries or other were derivatives of prior low power hulls moved by sail or human effort. The beautiful conversion posted above looks like a Whitehall hull and as the poster suggested suitable for low power electric or gas propulsion.
By the 70s a significant divergence between commonly seen sail and power hulls occurred with hulls more specifically aimed at their mode of propulsion. That has continued to the present. Even the classic traditional heavy displacement full keel double ender or canoe stern sailboat was no longer like similar hulls moved by steam. Remember first came sail. Then sail with power added but sails remained. Then pure power and the engine on a sailboat was a low hp auxiliary screw. Powerboat hulls initially were derived from sailboat hulls in many cases but that hasn’t been true for over a century. The low aspect keel forms were sold because they looked “salty “ not because they were a good hull form for a sailboat. I’m a huge Perry fan and have owned, blue water raced and cruised several of his designs or those of gentleman Jim. Have also owned other full keel sailboats. Although I think a poor choice compared to restoring a boat designed for power perhaps such a boat may be the least bad choice. Another least bad choice would be a center boarder mostly dependent upon form stability. Eliminate the board and ballast as necessary as to allow a modicum of righting arm but not to produce a poor comfort quotient .

 

[Jeff F]

Another least bad choice would be a center boarder mostly dependent upon form stability. Eliminate the board and ballast as necessary as to allow a modicum of righting arm but not to produce a poor comfort quotient .

Yep.

 

[Jeff F]

Hippo, I think D/L really matters in the earlier efficiency debate.

I've traveled the ICW end-to-end in 3 boats:
1. 1984(?) Jeanneau Sun Fizz, Perkins 4-108
2. 1978 Mainship 34, Cummins BTA 250
3. Escapade. 49' LWL, 35k disp, JD 4045T

Coincidentally, my average speed was very similar, 6.5 - 7.0 knots approx

Wanna take a shot at mpg?

 

[PierreR]

Hippo, I think D/L really matters in the earlier efficiency debate.

I've traveled the ICW end-to-end in 3 boats:
1. 1984(?) Jeanneau Sun Fizz, Perkins 4-108
2. 1978 Mainship 34, Cummins BTA 250
3. Escapade. 49' LWL, 35k disp, JD 4045T

Coincidentally, my average speed was very similar, 6.5 - 7.0 knots approx

Wanna take a shot at mpg?

I'll take a shot. They were all better than mine and probably very similar in MPG. Probably around 5
mine is around 3mpg @ 7 knots
I have a high D/L ratio

 

[Cartouche]

Mmm. That's one limitation. Lots of folks carry Jerry cans. Easy to get 1,000 miles slow. I've often thought they'd make decent river boats.

But you've got other practical limitations - draft
- comfort in big waves
- most people you encounter will assume you're indigent. You're not going to want to try anchoring too long anywhere.

I forgot slow!

it's going to roll a lot more than a trawler with no mast had lots of both Power & sail.

 

[rslifkin]

I’ve always thought the good road to a conversion is finding the right hull design. It’s my opinion that the conversion hull best have full ends. Something almost impossible to find. Sailboats are designed mostly to run well below hull speed. Most trawler men will be expecting to cruise at hull speed. That’s pushing most sailboat hulls. Sailboat hulls are usually fine at the ends and fat in the middle. A recipe for rolling w/o a mast and big time pitching. Most of these problems will be solved w a full ended sailboat hull. The only one I know of that has full ends is a 27’ Albin w the rudder ahead of the prop. But if you find the right hull a very good trawler can probably be made. But there’s other problems w the idea like most sailboats old enough to be cheap have a short WLL. And if you find a NA to help he probably hasn’t ever done a conversion. Or thought about it. Or did it w the wrong hull and has horrible things to say about conversions.

Thinking about that, the more modern sailboat designs (wider stern, more form stability, less ballast) likely make better powerboats than a lot of older designs did. They may still need some ballast trimmed once the mast is removed, but I'd expect it to be less of an issue.

 

[Jeff F]

Thinking about that, the more modern sailboat designs (wider stern, more form stability, less ballast) likely make better powerboats than a lot of older designs did. They may still need some ballast trimmed once the mast is removed, but I'd expect it to be less of an issue.

Depends on what you mean by older. There was a dark period when a lot of sailboats made terrible motorboats and just OK sailboats.

 

[Hippocampus]

Earlier the SC52 of Lee was referenced. That hull was optimized to go DOWNWIND. Such similar designs were commonly called sleds. They were uncomfortable under power and uncomfortable under sail going to weather. The current generation of slice of pizza boats would likely make truly miserable power boats. The footprint at the water line is actually very small. The reason they dominated the race circuit is they have such a small wetted surface but don’t have as much of the difficulties of sleds going to weather or in heavy weather. The wetted surface varies little when flat or heeled. The ends are very light. They are not made to squat. Look at the long low displacement motor boats and notice the NAs did not follow the form of these boats. Although sterns are slightly wider it’s nowhere close to the extreme as seen in Open derived forms. One was designed to function at a heel (sail) and one to function when flat (power). The production boats made to look like the RTW racers usually fail to derive the benefits of that hull form. The racers are ultralights. Weight is the enemy and expense of prepreg carbon justified. Pleasure boats need to carry significant weight. Put a hard chine and a wide stern on a boat doesn’t change that fact. You can use a hammer instead of a screwdriver but a screw is still made to be turned. We can argue about this ad naseum but if you want a powerboat it’s best it has a power boat hull.

 

[rslifkin]

Earlier the SC52 of Lee was referenced. That hull was optimized to go DOWNWIND. Such similar designs were commonly called sleds. They were uncomfortable under power and uncomfortable under sail going to weather. The current generation of slice of pizza boats would likely make truly miserable power boats. The footprint at the water line is actually very small. The reason they dominated the race circuit is they have such a small wetted surface but don’t have the difficulties of sleds going to weather or in heavy weather. The wetted surface varies little when flat or heeled. The ends are very light. They are not made to squat. Look at the long low displacement motor boats and notice the NAs did not follow the form of these boats. Although sterns are slightly wider it’s nowhere close to the extreme as seen in Open derived forms. The production boats made to look like the racers usually fail to derive the benefits of that hull form. The racers are ultralights. Weight is the enemy and expense of prepreg carbon justified. Pleasure boats need to carry significant weight. Put a hard chine and a wide stern on a boat doesn’t change that fact. You can use a hammer instead of a screwdriver but a screw is still made to be turned. We can argue about this ad naseum but if you want a powerboat it’s best it has a power boat hull.

When I was thinking modern sailboat hull, I wasn't quite thinking pizza slice race boat. I was thinking more like late 2000s / early 2010s Beneteau. Beamy, fairly wide stern but still tapered in, minimal to no immersed transom, etc. They still won't make a great powerboat by any means, but if you got your hands on one with a trashed rig, etc. cheaply enough it would likely be possible to get reasonable results from a conversion. Certainly far better than you'd get from converting something like an IOR era boat.



The biggest issue with some of those designs is the very fine, shallow bow that makes them prone to pounding and means they struggle to carry any kind of decent ground tackle weight, especially if you want to use the factory provided forward water tank. But those issues apply as a sailboat too, so they wouldn't be a new problem in a conversion.

 

[Pete Meisinger]

I thought the discussion of steadying sails had been put to rest. Oh well, I'll jump in with two cents worth.

1) You cant sail a trawler. The drag on just the locked prop will pretty much keep you dead in the water. Then there is the square stern and all the other trawler hull design factors which prevent you from sailing it.

2) A converted sailboat would make an efficient trawler BUT: No deck seating, no flybridge. You might have a dodger but it will not keep you dry in a real rainstorm.

pete

 

[psneeld]

1. Steading sails aren't about sailing, they are about dampening roll under certain conditions. Some rigs (most are not well designed) on some trawlers seem to work OK.

2. Buying a junker sailboat and cruising in a tropical/semi-tropical climate... people worry about rain less (often use the opportunity to shower) and throwing up an inexpensive hard dodger or even pilothouse is common.

I saw one sailboat I saw headed south in Florida (might have even been electric propulsion) had virtually the entire boat set up with a full length cover made from solar panels.

 

[CharlieO.]

I've chimed in on this interesting discussion, When I think if this conversion I'm thinking of something under 25', a NYS canal cruiser. I think some people on this discussion are thinking larger sail boats as a conversion. Heck, I came across a 17'er for free on a trailer, luckily I already have a boat that keeps me busy. But something like that could provide a lot of enjoyment for the right people.

 

[Jeff F]

Such similar designs were commonly called sleds. They were uncomfortable under power and uncomfortable under sail going to weather.

Have you spent time motoring or sailing upwind in a sled?

 

[Nomad Willy]

I've chimed in on this interesting discussion, When I think if this conversion I'm thinking of something under 25', a NYS canal cruiser. I think some people on this discussion are thinking larger sail boats as a conversion. Heck, I came across a 17'er for free on a trailer, luckily I already have a boat that keeps me busy. But something like that could provide a lot of enjoyment for the right people.

You make a good point Charlie.
The bigger the boat gets the less it’s desirable for a conversion.
But the bigger boats are less perfect than unacceptable.
But also there’s much more to gain saving money in bigger boats.

 

[sean9c]

I have, they rip.

Have you spent time motoring or sailing upwind in a sled?

 

[PNK]

converting sailboat to power

I didn't see mention of the size sailboat you are looking at, but I sailed a friends 42' sailboat back north from Vero Beach, most of that in the ICW, motoring most of the way except for 3 days outside. For me the biggest difference is light, and comfort. We spent several nights on the hook, but there is no really comfortable place to stretch out in the cockpit, and below gets way less light and air than a trawler. I would rather be preparing and eating a meal, for instance, while looking at the scenery.
Also access to engine and any other machinery is usually much more restricted.
You might find an easier project starting out with a power boat, rather than converting something. You'll sip fuel for sure, but you will also probably never get more than 6-7 knots, and unless you make one of the suggested mod's to the keel and rudder, you will also be limited if you want to get into shallower waters.
PNK

 

[Jeff F]

I'll take a shot. They were all better than mine and probably very similar in MPG. Probably around 5
mine is around 3mpg @ 7 knots
I have a high D/L ratio

Wanna try ranking them? I'll award prizes at some later date

 

[psneeld]

I believe the OP was discussing a hurricane damaged boat...true the desired boat wasn't discussed.

But if just looking to buy a damaged but still seaworthy (not true bluewater or ocean crossing) sailboat and not an "instant" or even "distant" dreamboat to have some fun with.... then I say explore the possibilities.

Think outside the usual boat buying box and many new doors open.

 

[Hippocampus]

Yes have raced large J boats and one offs. One sail on a Pogo. Haven’t owned one but have crewed. Over the last few years on Attainable Adventures and Sailing Anarchy there’s been threads and discussions about what hull form makes for a good blue water cruising sailboat. Basically comparing a balanced hull to a slice of pizza. A cruising boat will only be driven as fast as comfort allows. One boat may have a hull speed far in excess of another but only average 2/3rds of hull speed. Another’s hull speed may be lower but driven at 7/8th of hull speed on average. While cruising the “slower” boat will have a longer days work. Also effecting how far you go in a day is how much attention and trimming is required and the willingness of crew to do it. My wife’s chronic complaint was “sit down already “.

One of things not discussed to date is draft. Since going to the dark side have truly enjoyed not dragging around a deep keel. Again if contemplating a conversation personally would avoid deep keeled high aspect fin keels. Especially those with balanced spade rudders.

 

[Jeff F]

Over the last few years on Attainable Adventures and Sailing Anarchy there’s been threads and discussions about what hull form makes for a good blue water cruising sailboat. Basically comparing a balanced hull to a slice of pizza.

One of things not discussed to date is draft. Since going to the dark side have truly enjoyed not dragging around a deep keel. Again if contemplating a conversation personally would avoid deep keeled high aspect fin keels. Especially those with balanced spade rudders.

I'm firmly in the uldb camp. Campaigned a 34' in the late 80s.

My next boat may be a MacGregor 65. Sail around the world or rack the mast and do more river cruising. 6 foot draft.

 

[Mako]

I love those M65's and almost bought one years ago. Well, I'm not a big fan of V-drives and even less of those big gas Mercruisers or whatever they used to install in them. Also IMO, you'd want to buy one ultra-cheaply, consider it a project boat, and completely rebuild it properly for bluewater cruising (diesel repower, all new portlights, electrical system, etc.)

 

[Jeff F]

I've got eyes wide open

 

[kehoff]

Years ago in the Indiantown marina, Florida, there was a 36 Gulfstar sailboat that was converted to trawler. They cut the keel and rudder down, added a pilothouse and added more power, tanks, etc. It was nice when complete and if I remember correctly, the couple went on extended cruises regularly. It was a huge project

the gulfstar was also a powerboat and the underneath was very similar, If I remember correctly

 

[Northern Spy]

The Willard 8 Ton sailboat is derived from the Willard 30 trawler hull.

So there's that...

 

[Simi 60]

“.

One of things not discussed to date is draft. Since going to the dark side have truly enjoyed not dragging around a deep keel.

From a multihull background I truly do miss being able to go over the side in 3 ft of water and give the bottom a tickle up
Or sneak in across a reef to enter one of our favoured lagoons, only accessible to the select few in the know.

But, with 7.5 ft draft that we have now there are other advantages
Where we anchor we generally have privacy as not many want to anchor out back in the deep
And, anchoring that far out biting bugs are at an absolute minimum, I can count on one hand the times we have had midges and mosquitoes disturb our sleep in the last 6 years aboard - on a cat it was biteys every time we anchored.

 

[Jmk2000]

A mast and boom can have several different uses. A nice paravane setup can actually be 2 masts and 2 booms if creative.

Man Now there’s a thought! Wonder if you could rig 2 booms off one mast for stabilizers