turning a sailboat into a motorsailor

Dave Gudeman,
Nowhere does it appear that you have sat down and considered what cruising ground you seek to venture into.
The type of boat is partially determined by where you are going and where you will live...
Living aboard the boat at anchor...
Live on land with the boat at a marina to go out once or thrice in a season...
Consider the region where you will sail/cruise/fish (East/West coast, North, or South)...
How many people in your immediate family that need to be accommodated with berths and personal storage space...
Is the boat to be available as a crewed charter of shared boat or you to occasionally charter, or your primary place of residence...
The need to take the boat into shallows (gunk-holing, crossing-shallows), operate on open ocean for extended periods of time and so-on...

Get all these factors sorted first as some options will mutually exclude other activities...

Then consider realistic annual maintenance costs, running costs and hours of use by you... Can you afford it and can you justify that option, - or is the ROMANCE in your heart over-ruling any logical consideration...

Are you one who expects your day drive (car) to be competitive in races, carry the family on vacations, nip in and around traffic snarls in peak-hour with the ease of a small motorbike, fold up so you can park it next to your desk at work, efficiently fetch the weekly groceries? - Likewise, do not expect a boat to multi-task...

 

We keep running into the laws of thermodynamics which basically say there is no free lunch. Displacement, power, hull type = speed. This always favors long and lean and light, and don't forget to make it light.
Enough "room" to live aboard means supplies to be independent for at least a couple of weeks. This quickly gets heavy unless you have freeze dried food and a watermaker instead of tankage. That's not cheap. How about sewage? Will you be running the boat to the pumpout every couple days or just dumping it in the marina and hoping nobody will notice? More tankage.
Making a 35-45 footer of any design other than a racing arrow go 15 knots means a big engine and that means big fuel draw and that means big tanks which weigh a lot which means a bigger engine etc.
A light, long cat (wide and long, the marina loves your $$$) would do it for sure, but not cheaply.
A cheap cosmetically damaged sail boat can be converted into a lot of things, but the generic 40' single diesel Taiwan Trawler at 8-9 knots and reasonable fuel burn makes a better apartment than any converted sailboat of the same length. And a TT fits into any marina.
In the 'old days' they had "Commuters" of 55-75', which would do 20-30 knots in gnarly conditions, but their huge Hall-Scott or Packard gas engines drank lots of cheap fuel and those days are not going to return.
And before that, steam yachts often sized 90'x10' gave high speed, but again not cheap.
Either pay a bunch of money and give up space to big engine and tankage in a lean boat, or just poke along and enjoy the ride like the rest of us, check out the pelicans diving for herring and watch for whales.

 

Masalai, some good food for thought, and I keep asking myself many of those questions as well.

Bataan, must we always allow reality to close in on us...?
I really like your posts, knowledge with common sence and a nack for telling it like it is! Everything is a compromise

 

Personally, reality smashes me over the head with a big club every time I ignore it. Any design is like a big math equation with hundreds of variables, and so as you said, compromise is what we wind up with, like it or not. Fair winds!

 

Even so, it's a popular way to get on the water for little money. I found articles on the subject Terminal Trawler and Strawlers, converting a sailboat to a low powered displacement cruiser. Adding a raised wheelhouse in place of a dodger on a sailboat seems to add function. HAs anyone done this?

 

Many sailboats have seen such conversions, though you have to be careful with smaller boats, when adding tall deck structures. Most sailboats are fairly low and intentionally so. With a standing headroom doghouse, you could upset the stability curve sufficiently enough to capsize the boat in some conditions.

 

"Adding a raised wheelhouse in place of a dodger on a sailboat seems to add function. HAs anyone done this?"

Many , but few if any ever see over 7K from a modest sized boat.

 

$30,000 worth of diesel on a cat that cruises at 10knots using 1 l/nm, is enough fuel to travel the globe
And I think your pricing is a bit off as well
I doubt you will get a decent rig, sails, wire and winches for that money

 

Well, I just made the number up. What would be a more reasonable figure?

But the argument about how much fuel costs is beside the point for a few reasons. First, once you burn the fuel it's gone, but a sailing rig has resale value when you sell the boat. Second, you can't put that $30,000 worth of fuel in the boat at once, you can only buy it when and where it's available --which isn't in the middle of the Pacific, for example. Third, there are reasons to sail that don't have anything to do with going anywhere.

 

I think if you asked some of the members here that have recently completed some cats you would find $50k plus may be more like the number.
This is for high quality gear of course.

I was looking at close to $70 k for all the bits ofr a 50ft cat

It does, but its value will be considerably less and will likely need extensive refurbishment costing tens of thousand of dollars.

Lets say $50k.
But you can have it earning 5.5% in a bank, or better elsewhere.
That'll buy a years supply of fuel.
And, I still have the original $50k.

So?
Plan your legs and make sure you have the tankage.

OK, but if that were the case you would be owning a dedicated sailing machine, not a powercat with an add on mast.

 

Wow, I should be looking for a boat that would get me to Oz if the banks are paying 5.50% now!

PAR, I have seen some fishy boats out there that are three stories hig and wonder why they don't roll over when someone jumps in the water to go swimming. I had nothing like that in mind. I think in adding on to a boat would be much like a house, in a way. The addition should look as if it were not added at all, it should be safe and functional yet blend with the overall design.

An older sailboat is usually overbuilt, heavy by todays standards and while there would be obvious issues, like the CG, windage, and stability, a box of sealed air higher than the deck may also provide better righting abilities if it's properly built. Personally, I wouldn't go with a green house high up, I'd like to see one with a higher roof that appears to be more like a coast guard cruiser...doubt that would be easy to find.

I guess outriggers are possible, but might really be a styling challenge, sponsons added might be another possibility, but attached would increase beam and might be a trailering problem suggested by the OP.

Being big enough to live on and being trailerable is some quest. That's why I was considering trying to build something like the Bolger Tenessee, 32' and 7 or so beam. I have not found a sailboat at 30+ feet that has an 8' beam, but one might exist.

Going at 15 knts, I'd say I would simply get a small rib for fishing and zip around on that and tow it if it would not mount on the live-a-board. Like staying in the diesel pusher RV and pulling a Miata. Life is a compromise.

 

"An older sailboat is usually overbuilt, heavy by todays standards"

However it EXISTS , which is open to question on the lightly constructed boats that wiggle thru the water.

Throw away is fine for the racing folks , much harder to justify on a cruiser.

 

I'll take overbuilt anyday--My present build, I can run the hull into a cement wall--hopefully it never happens -- Heavy and slow is ok with me, (something like the owner is getting to be)

 

Agreed! I am never going to race (unless I know I can win against that canoe, lol) heavy, durable, slow, safe is fine for me. Cheap and economical to operate.

 

Weight IS a bummer if your a racer , power or sail.

But for power cruisers that run in slow displacement mode SL 1 or so,

the simple rule of thumb is 2 or 3 hp per TON!!! 2240lbs. That a lot of hull weight..

A heavily overbuilt boat that cost 2 or 3 hp extra to push would hardly be noticed by the usual way too oversized to be efficient diesel.

FF