Fuel Efficiency

our tug with a detroit 12-71 is running straight used cooking oil we do preheat it with a oil cooler reversed to work as a heater it smells better runs quieter and a bit smoother
 
I always wondered why boat transmissions never had gears on them? Why are they always a single speed? You would think you have have maybe a two or three speed transmission where you could effectively shift to a higher gear and lower the engine rpm, thus increasing efficiency.

Any thoughts?
 
quote:

Originally posted by dl2525

I always wondered why boat transmissions never had gears on them? Why are they always a single speed? You would think you have have maybe a two or three speed transmission where you could effectively shift to a higher gear and lower the engine rpm, thus increasing efficiency.

Any thoughts?






There are boats out there with 2 speed transmissions. I have been on a few See Vee's and Cabo's that have them.
 
quote:

Originally posted by GonzoF1

Doesn't it need a pre-heater of some kind? I'd hate to try it and have it NOT work, then have a tankful I can't use and can't get out of the tanks.

Any marinas even offering B-20 yet or am I going to be hauling it down in 5-gallon cans?






"biodiesel" is about the same consistency as regular diesel and works well in about any engine without conversion, as opposed to vegetable oil which is thicker and requires preheating. Kevin uses vegetable oil, but I'm told it's a bit too heavy for the Lucas fuel pump on a Perkins.

No marinas near ME sell either one. I buy B-100 55 gal at a time and gravitate it into the boat behind my house. Might not be so simple at a marina.

A "blend" is easy... simply get 100% and add it to the fuel already in your tank (mixes fine with dino-diesel). Start out with a low percentage and increase it as you become more comfortable with the stuff. If you think you've got too high a percentage, add more regular diesel.
 
The hybrids increase fuel economy mainly by using "regeneration" where instead of wasting energy heating up brake disks/pads to stop, a generator is engaged when the brakes are applied and the energy used to stop the vehicle is converted to electrical energy and stored in a battery. The hybrid will loose all of that regeneration effect when on the highway, and of course if you are going up hill all day long as you are in a boat, the economy would not look so good.
 
Most boats don't have multi-speed transmissions. A way to look at why is that they are always going up the same "hill". When you climb a really steep hill in a car or truck, there will be a gear that you won't be able to shift up from without losing speed. That is akin to the gear that your boat runs in. It doesn't need a lower gear than that because it is easy to push a boat up to hull speed--so it really only needs one gear. An exception to this is a fishing trawler that has to pull nets--some of them have variable pitch props, for obvious reasons.
 
I just used the Prius as a "for instances", not necessarily the answer to my own question. Yes I know there are efficient hull shapes and that going slow in a displacement hull is efficient, and that wind is free, but I'm wondering if we could "think outside of the box". Pull out all the stops. Lets take an efficient hull shape, maybe a new (or older) drive mechanism (paddle wheel?) and couple it with an efficient propulsion device to really improve the world of power boating.
 
Long skinny Amphiprius with magnetohydrodynamics drive? Or a Picnique Boate' w/ 2x/trolling motors powered be weedeater/alternator Thudomatic Drives? When I was a tiny tot, baking soda or Alka Seltzer tablets powered some of my 1st yots pretty nicely in the tub. Fuel got a lot more expensive after that.
 
Soundings Magazine has been running quite a few articles lately on improving fuel efficiency in boats. They even had a story a few months back about a concept for a boat that used photo-electric panels to charge batteries on the premise that a recreational boat is typically used very occasionally, and that most of the time it is in the slip. The PE panels could be used to charge up a large bank of batteries and that in conjunction with a diesel/electric drive system could make a very efficient cruiser. The weak link with all the scenarios involving electic/hybrid set-ups is the batteries. Even a bank of Lithium Ion batteries (read:$$$$) has to be pretty big to equal a gallon of diesel fuel (or gas, for that matter). Who wants to be a billionaire? Just be the guy (or gal) who comes up with a good way of storing an amount of electrical energy equivalent to maybe 20 gallons of gasoline. IMHO that is the holy grail of any kind of move into new ways of powering boats. In the meantime, for us regular joes, slower boats, getting away from deep vee boats, not running over fish to catch fish and myriad other ploys will be what we will have to do to cope with rising fuel costs.
 
"The weak link with all the scenarios involving electic/hybrid set-ups is the batteries."

I agree.

A few random numbers:

One type 31 12v lead acid battery, used in a 100% to 50% cycle, can store about 500 watts ( and weighs about 60 lbs )

The equivalent weight of Lithium/xx cells holds about 3x as much energy ( I didn't check. I think they do.... ) They also cost more per watt stored than L/A.

1 hp = about 750 watts
 
Modern boats are built with the marina and wife in mind. They are beamy, and often a semidisplacement hull. If you go to a true full displacement hull, limit the speed and HP, as well as beam, 6 miles per gallon are very possible in boats 45 to 55 feet long. I have owned sailboats, which were true motor sailors, and would sail and power at 7 to 8 knots. These boats had 80 hp and at 6 knots would burn a gallon an hour, using the sails one could do better in fuel economy, especially with a controlable pitch prop. Some of the old "launches" which were narrow and had low HP engine also got similar economy. "Idle Wild" is a 57 foot narrow beam circumnavigator power vessel with 57 hp and averaged about 5.5 miles per gallon, including doing the North West Passage--she is still for sale. Problem is that no-one wants that type of boat.
 
Check out this web site for a more accurate formula for calculating hull speed:

www.psychosnail.com/BoatSpeedCalculator.aspx

Bob
 
Speed and economy are inversely related as are speed and seakeeping ability. The flatter the hull shape the faster is will go ounce on plane and the easier it will plane. Deeper rounded hulls wont plane but are more easily driven through the water at speeds below where hull speed. Vee shapes are in-between, not as fast or economical but better sea boats.
Everything in boats is a compromise. If you want a fast, most economical planing cruiser look for the flattest bottom but don’t be surprised when it pounds like cazy an blows around like a kite in a breeze. OTOH the most economical hull speed boat will resemble a sail boat for the simple reason that they are designed to be slippery in their intended operating speed range. They become very unslippery however if you try to drive them too fast.
 
Thanks for the comments so far, and RNBENTON, thanks for the website. I've always wondered why bean is not a factor in the hull speed equation. Seems to me if you have a 30 ft LWL with a 2 foot beam, the characteristics are going to be different than a 30 ft LWL with a 15 foot beam.
 
quote:

Originally posted by Kuredu

quote:

Originally posted by cwms

The owner of our marina has a 40' single diesel trawler and I believe he gets about 5 mpg at 7-8 knot. In my 38' Carver, if I throttle back to 7-8 knots, I get about 1 mpg.
So yes, there are more fuel efficient technologies out there including the oldest - sail.






At 5kn I get 4.5 mpg and at 8kn we get 3.2 mpg on the 411 with twin 380 QSB's.

I saw an interesting system on a new trawler being fitted locally - besides the single diesel as main propulsion they had added a secondary electric motor in the drivetrain. This could push the trawler at slower speeds (I believe it was around 4-5kn) and was powered by a secondary smaller diesel generator which used very little fuel. I thought that was a neat "hybrid" idea and have been wondering how difficult that would be to retrofit somehow.








this is not a hybrid, its a get me home motor. very common on large single engine configuration trawlers.
 
quote:

Originally posted by Roy

Seems to me that if a Toyota Prius can get almost twice the miles per gallon as a comparable purely gas driven car, there ought to be a more efficient technology to drive powerboats. Any thoughts?






Seems to me the Prius is more of a marketing breakthrough than a technological one. The operating statement in your question was "comparable". Few cars are comparable to what prius has put out. If they shared the tiny size and construction and price point, it would be easier. Much easier.

Think about it. What is easier. Design a fuel efficient gas car, or add the complexity of converting dynamic energy into static storage, then back again, with all the associated inneficiencies losses, added weight and the environmental impact of creating, maintaining and ultimately recycling/destroying all those batteries and heavy metals. The problem bigger than the engineering is one of marketing. Prius is nothing more than a marketing success. It's no more of an environmental success than is the cash for clunkers deal. Neither makes sense on paper. Plus, diesel electric is often done for reasons other than purely efficiency. There are a lot of advantages to an electric drive motor, once you already have the other gear onboard. Cars usually don't and frankly don't need them either. I'm not sure the benefits outweigh the weight once eco considerations are thrown in. It's hard to beat pertroleum fuel for the efficiency of converting stored energy in the fuel directly to work.

Don't believe it. Here's comparable for you. Why don't you look at the Honda Civic HF that was around back in the early to mid 80's. Similar general size as the prius, but it could get at the high end of the 50-60 mpg range. That was over 20 years ago. Imagine what you could do today on that platform. But nooooooooo, we have to add batteries, cause you know electric doesn't generate polution because that's as sophisticated as our eco freaks can figure out.

Boats are demanding of power, so marketing tricks are harder to pull off. Then again, my 1980 Tolly with less than fuel efficient cat 3208's compared to today's standards will routinely get me better than 2.5 mpg efficiency as measured by floscan's. That's less than 5gph between both engines. On a good day with favorable conditions I'm burnin less than 4gph for both engines. Market wise, its one of the least desireable power packages for the 48. People want to go fast. Period. You can't make what doesn't sell. Prius's sell, the old Honda's didn't. Difference is a 300% improvment in marketing with a 20% improvment in technology.

Biodiesel is great....so long as there is a continued source. Used cooking oil is not quite so cheap anymore as it once was and the "free" fuel now costs more than off the shelf diesel. Plus, look at the disaster that was corn ethanol in terms of both the economic and environmental impact of actually burning MORE dino fuel overall. Will be really interesting to see if algae can come through but otherwise, yeah I'm a skeptic that the math is really working here.

So...maybe lets not be quite so quick to fall for all the "advances" in fuel technology. Sure, there is a lot to like coming down the pipe, but we really need to quit being so gullible with the half truthed eco branding going on.

Since I can be pretty low impact with my 1980 technology, why don't we all just agree to be as frugal as we can and not worry so much about rushing too quickly to things that are in fact causing more problems than they are solving just because we have good intentions. The last thing I personally want to see is more MTBE going into our waters because some eco nazi freak who smoked a little too much pot and spent a few too many mornings getting up late cutting math class but showing up to theatre in the afternoon session didn't understand the facts of the situation.

Owning a prius is about snooting your eco nose at your neighbors, not about being ecologically sound. Maybe its just a bad example, but its pretty clear boats and boaters are about to get targeted. Soooooo, yeah I'm a little hair triggered that our boats are about to be "priused" into something they shouldn't be. Just like no discharge zones that don't allow treatment systems.

You want to save fuel? Great. Stop trying to tune the 10% equations in finding efficiencies in getting more work from the fuel. Start trying to eliminate the need to use the fuel in the first place. THAT's where you can decrease not by a factor of 10% but by factors of 80%, 150% or even 200%. You want to use batteries to store energy. Great. But only if we don't burn carbon fuel to generate it. Lets use nuclear plants ONLY.

As for the sailboats.....My instincts are that sailboats ARE in usage fairly efficient. But...I think is was Beebe that figured out that the cost and maintenance of all that rigging over the course of an equal number of miles sufficient to encompass the practical lifespans of both diesel engines and rigging. Well I guess it turned out that the sailboats were consuming enough materials along with the associated costs of those materials to be roughly comparable to the costs of diesel machinery over a comparable number of miles travelled. If we consider the ecological costs of creating fittings/etc compared to engine blocks, well the ecological costs are actually not as different as one might expect. Like cash for clunkers, we really need to consider the vast amounts of energy that goes into creating an object. Whether it efficiently burns fuel to operate or not, it is VERY expensive to allow machinery to not operate over a maximum life span.

Lets not get Priused in our boating communities.
 
"Nuclear plants ONLY"

Yeah right. My guess you'll see a resurgence in "solar powered" sail boats before you see much in the way of "nuclear powered" electric boats.
 
Hybrid is available now...at a cost. Octopus is diesel electric.

WRT multi speed transmissions, they have been around for years. The owner of my marina near Ft. Campbell, KY had one on the family's 28' Pacemaker. The other option is a controllable pitch prop (CPP). I saw an after market bolt on device that converted a Mercruiser to a CPP at the Genoa boat show in 1990. IMHO, a CPP is the only way one can mimimize the compromise of boating we all have to do each time the load changes.
 
Here's probably the most "fuel efficient" powerboat on the market, the DSe Hybrid:

DSeBow_MG_1311_600pix03.jpg


I have some friends that put a deposit on one. They had it refunded once hull #1 was sea trialed and it became clear that the cruising speed was going to be 4.5 knots under solar alone, and 9 knots with the diesels cranked up. If I were a tree huger, I'd opt for a nice sail cat before this thing. I can only imagine the environmental impact from the manufacturing of all the solar panels and batteries this thing requires. Heck, I'd like to see them sea trial it without the batteries as I bet they'd pick up speed with the large reduction in weight.
 
quote:

Originally posted by Billylll

The Maqinship MK 34 Trawlers origins date back to the 1st Oil problems in the US. The economy was bad similar to the economy we are in. I wish I had one and not the model I have. They can have soft decks but many have survived or been repaired. There were 3 models the MK1-3. Great boat they can be had for a song right now. I have seen a few modernized with new Cummings. This is a very nice boat for it's time and the current times.
Bill






Ever since gas hit $3+ I've been wondering why there are more boats like the old Mainship 34, or even the Midnight Laces. Part of the fuel efficiency problem is due to the wider and wider beams on new boats, although I know it gives more interior space. Not to pick on them but since they are related to Mainship, Silverton has some really wide beams in comparison to length, and it shows in both lower mpg and slower performance.

Do narrow beam semi-displacement hulls give a lousy ride? Are they less sea worthy? When I get back into boating, I won't need to be going 20-25 knots, but a trawler at 7 knots all the time does seem a bit boring. Seems like a boat that cruised at 12-14 knots that might top out around 18 knots that good gas mileage would a good solution. Anyone have any experience with a semi-displacement boat they can share regarding ride and economy?
 
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