Efficient Powerboats vs Efficient Sailboats (Running Cost Comparison)

[northerncat]

on this subject roger hill recently designed a 35 ft cat powered by 2 yamaha 60's and it will do 18 knots on one motor, so you have a cheaply powered planing cat that is conservative on fuel consumption, the yammies use about 8l an hour at 4000rpm which is their cruising speed, reading the article a few months ago made me want to build one, i think they claimed a top speed of 25knots, personally id put etecs on the thing, i wish id bought my own copy of the mag

sean

[Jacana]

Anyone on east coast Brissie, Gold Coast ,have access to or charts for sale or copy need New Cal, Fiji Solomans for next trip Regards Geoff.

[northerncat]

Originally Posted by Jacana

Anyone on east coast Brissie, Gold Coast ,have access to or charts for sale or copy need New Cal, Fiji Solomans for next trip Regards Geoff.

what this has to do with motors vs sails i cant get, stop being lazy and start a new thread
sean

[Jacana]

Relatively new to this caper and have read about a couple of people in Brissie who have sailed there dont know how to find where i read it on this website I take it you dont live in Brissie or Gold Coast but thank you very much for all your help.Happy New Year Geoff.

[Therapy]

cat man do

Saw this on another thread today and wondered if you had thought of it while deciding what to do about sails vs no sails.

Rig: Easily reefed and furled fully-battened Pacific rig with design features from fully battened lug sails and Polynesian sails. Un-stayed masts with no potential failures due to stainless stress or corrosion fatigue. Maximum and working sail area 2400 sq. ft. The biplane rig is self-tacking and requires no sheet winches, despite its large sail area, due to its balanced design and 7 to 1 sheet purchase. Using this rig should save over $100,000 USD compared to a marconi rig, which isn't a lot compared to purchasing a large catamaran retail, but it is a huge amount of money to the home builder. This rig saves the builder 25% to 33% of the cost of building the boat.


65 Foot Sailing Catamaran Design by Tim Dunn


http://www.cruisersforum.com/forums/...tml#post127110

[cat man do]

Originally Posted by Therapy

cat man do

Saw this on another thread today and wondered if you had thought of it while deciding what to do about sails vs no sails.

I wasnt wondering, I decided before I started that it was a powercat

Thanks anyway

Dave

[elcubanito]

Ok, I was crew for a couple of weeks in a Nordhavn 55. I think this may be the boat your looking for. It was very efficient for a diesel and it dida bot more that 1 nm to a gallon

[David M]

double post..woops

[David M]

One factor that is not being considered is what is a persons time worth? If you charge by the hour from point A to point B, then a powerboat is cheaper. This is why the worlds merchant marine is 99.999% power driven vessels.

[Weyalan]

Originally Posted by David M

One factor that is not being considered is what is a persons time worth? If you charge by the hour from point A to point B, then a powerboat is cheaper. This is why the worlds merchant marine is 99.999% power driven vessels.

When I go sailing, the journey is as (or more) important than the destination. I don't necessarily want to get there any faster, I want to have one foot hooked over the tiller, broad reaching at, say 7-8 knots, with one arm around my girl and a cold beer in my fist... The anchorage will still be there when I get there...

[Amgine]

The merchant marine has been adding sail-assist to more and more vessels. There's a series of 6 panamax freighters using computer-controlled junk rigs. MS Bluegrass Skysails just left on its maiden voyage flying a kite*. Quite a number of tugs on the US east coast have sail-assist rigs, though I haven't seen many of them actually using them. And of course almost every cruise line has one or another variant of sail assisted propulsion in their fleet.

These rigs are used to save fuel, not supply all the power. They use them because it's cheaper, not faster, and cheaper is often smarter in economics. Shelling out £400,000 for a sail* is not a decision made for romance.

Amgine

* Daily Mail article 22 Jan 2008

[David M]

Originally Posted by Amgine

The merchant marine has been adding sail-assist to more and more vessels. There's a series of 6 panamax freighters using computer-controlled junk rigs. MS Bluegrass Skysails just left on its maiden voyage flying a kite*. Quite a number of tugs on the US east coast have sail-assist rigs, though I haven't seen many of them actually using them. And of course almost every cruise line has one or another variant of sail assisted propulsion in their fleet.

These rigs are used to save fuel, not supply all the power. They use them because it's cheaper, not faster, and cheaper is often smarter in economics. Shelling out £400,000 for a sail* is not a decision made for romance.

Amgine

* Daily Mail article 22 Jan 2008

Ok, I take it back. Closer to 99.8%

It will be interesting to see if the sails pay for themselves given they can be used only when the apparent wind is aft of the beam. Ships generate a LOT of apparent wind which of course shifts the apparent wind forward of the true wind. For anyone who has spent time on ships, the apparent wind almost always forward of the beam. This means that launching a kite with the wind from forward of the beam would slow the ship down. There is probably an optimal angle and relative wind speed in degrees aft of the beam and relative wind speed, where it makes no economic advantage to launch a kite until the wind reaches that point.

[Amgine]

Mmm, from my reading it looks like about .02% of commercial freight has some form of sail assist, but industry media are tossing numbers of 30% or more in 10 years. A much larger percentage of the cruise lines tonnage has sail assist.

Remember the kite is flown 300m off the deck; the displacement wind and turbulence doesn't affect it.

[alohaboat]

Originally Posted by David M

It will be interesting to see if the sails pay for themselves given they can be used only when the apparent wind is aft of the beam.

I have a big gennaker for my 40 ft. trawler. I power down wind over 50% of the time so the sail is up most of the time. Without the sail I get 5 nmpg at 7.3 knots. With the sail up, I get close to 6 nmpg. Since I am only moving at 7 to 8 knots, apparent wind direction is usually not an issue.

Since I have a single engine, the sail also serves as an emergency 'get someplace' device. I have never had to use it for that purpose. Speed under headsail only depends on wind strength but it is NOT impressive.

Cost of the sail is minimal. Just pick a used one up someplace. The luff dimension is the only critical measurement.

Patrick
Willard 40PH
ALOHA
La Paz, MX

[Beemer]

Hey guys, I'm a total newbie to the N-MPG foray, but I've been an auto and motorcycle racer and engine builder for 32 years now and a few automotive engines have given me ideas. I'm sure you all remember the Geo Metro XFI (suzuki swift for others) that had a 3 cylinder single compression ring pistons and was getting about 60mpg on the road WITH air conditioning running.

Take that turbocharged motor, which could be had, but only with a conventional ringset 2 compression ring setup, run XFI pistons with a total seal compression ring, and moderate boost and you've certainly got 50-60 horsepower engines that sip fuel. The turbocharger will take the load well at lower rpm's too.
We tried a prototype layout with an old inboard 20 foot runabout that originally came with the old pontiac "Iron Duke" four cylinder 3 liter motor. (It was a Galaxy boat, fairly decent hull but it was a stern drive, so we boarded up the transom for the test and ran a prop shaft with two U-joints and ran the engine at a slight angle as well.

Now that is NOT a trawler type, low speed efficient hull, it is meant to plane, but it still managed nearly 7nm per gallon of fuel at 10 knots. Before we could finish the project the boat was stolen. But we proved that little motor could do it.

I have a friend who took the 3 cylinder diesel motor out of his Honda riding lawn mower (this was the 4wheel drive hydrostatic drive and it also had power four wheel steering, and live hydraulics front and rear..but the frame rotted out.

He ran it in HIS sailboat. I think his boat was a 30 foot single mast with a jib or spinnaker (I'm NOT a sailing vessel guy) The engine weighed all of about 100 pounds max and took up the space of a briggs and stratton V-twin riding mower motor. Incredibly quiet.

Those diesels generate so little heat that just running them with a conventional automotive radiator built into the engine cover with an electric fan is all you need..no raw water cooling.

His goal was to have that engine running a 20kw generator head, and he wanted to use 2-3000 pound forklift battery to store excess power. He was STILL going to use sails, but the batteries would be placed in the keel in place of lead or other ballast (Forklift batteries can come in any shape you can imagine).

So since you're carrying a few tons of ballast anyway, why not have it be in the form of batteries?

He actually built a winch powered shelf rack that went down into his former ballast area, so he could stack batteries on top of each other. You did have to decouple the motor/prop shaft to use the battery lift, but since the engine was low enough to be used as ballast as well, he was fine.

He had four 130 watt solar panels hooked into an MTTP controller, and the batteries were configured to provide 48 volts. His last part of the plan was to procure a 30 horsepower electric motor to run off those batteries..(essentially a forklift electric motor) in direct drive, since an electric motor has its power and torque pretty much at any rpm)

However, he was so tickled with how efficient his little honda diesel motor was, that he found a TINY turbocharger for it, and was pushing right around 35-40hp out of the little thing. He WAS going to bolt that motor to a generator head and then run an electric motor in place of the diesel motor, and move the diesel motor to the most advantageous spot for weight/balance. However, the extra weight versus how cheap it was to run the existing diesel engine, and the cost of a 30hp electric motor sank the design. But he DID still use the forklift batteries for ballast, and he could literally run everything he had for a week or better just using the solar panels and batteries.

He did have a hundred amp alternator on the motor as well,

His final idea was to somehow couple the generator so that it also worked AS an electric motor as well.

That way you only have ONE set of windings that can serve two purposes. However, he passed away before he could complete his brainchild. I could probably sketch it out, as I did see his plans. Essentially he used an electromagnetic clutch to couple the engine to the genset, which drove the genset and produced power, while running the genset shaft out to the prop shaft, so when the genset was charging, it also was propelling the boat. When the batteries were fully charged, the clutch would automatically decouple and kill the engine, and the genset now became an electric drive motor using 48 or 72 volt. The voltage was selected automatically via a bunch of relays that would engage in 24 volt parallel while charging (remember also that we were charging the batteries with a 24 volt alternator). When the batteries were fully charged, the engine decoupled and the relays reset the batteries to run in series (he had three forklift batteries, so I'm guessing that was around 9000 pounds of ballast. Because the batteries were sealed gel type batteries (like the oddessy batteries only HUGE), they didn't outgass much and whatever did outgass went out thru a hull port above the waterline. Then the boat went on electric drive unless the user decided to shut down for the night. The main engine would automatically restart when battery power reached less than 50 percent. The alternator also charged four "house" batteries as well. While running that little turbocharged diesel motor under the load of the genset was not the most fuel efficient way to do things, switching back to electric drive REALLY maxed out the literes per mile.

Not to mention, if the engine blew, you still had those four big solar panels giving those three huge forklift batteries everything they could suck down.

He also wanted to experiment just running a sailboat on a lister hit and miss diesel engine that was around 12hp or so, single cylinder, running that same genset and then running by itself both on diesel and WVO, and cooling that diesel motor with the WVO, which needed to get heated up to flow and burn properly anyway

However, the listeroid engines you can find today are usually indian made and are cast iron..and quite heavy.

He also found out that there are a LOT of Yanmar diesel motors in the reefer packs on refrigerated over the road trailers that can be had for a song..like a hundred bucks or so.

Just a few ideas to throw out there to you all.

I have a 30 foot 1973 pacesetter sedan flybridge that I just bought and I was seriously considering replacing the current crusader 327 chevy motors with a pair of listeroids or little yanmar diesels, but then I remembered that you have to get one spinning opposite of the other one..and I'm not sure you can do that with a listeroid motor. The weight is equivelant to a small block chevy though. Another idea is to use the chinese CHANGFA 22hp diesel engines..they're german designed, and the germans also did the tooling..VERY reliable, decent on fuel and you can overhaul one by yourself in about 5 hours with simple hand tools.

Hope this confuses everyone, but Mark wanted to patent the idea..and he probably should have, and I more than likely just gave away a few million bucks to some enterprising young captain who gets a working prototype built and patented before me.

Cheers
Dave