Diesel Outboard

J

journey on

New member
Well, since that Italian outboard went down the tubes (and I can't remember who,) and Yanmar quit, this appears to be the latest effort. It's from Germany and they've been working on it for at least the last 7 years. First for a motorcycle and now an outboard. It's being funded by some political subdivision in northern Germany

It's a parallel twin, with 2 cranks, 2 pistons and 4 con-rods. I guess it cancels the vibration and allows one to install it into small packages. Here's a page on the engine: Neander Engine

Here's the link to the outboard, which has a snazzy outside: Neander Outboard Tests

And here's a press release about the development by a Dutch company: Neander Shark develops outboard motor

Any comments or further info are welcome.

Boris
 
Boris,
Thanks for posting this info. I followed all of the past outboards over the years and one thing that always and still stands out is the weight. This new engine is still very heavy for its output capability, but hopefully the new technology will aid in getting the power to weight ratio more inline with 4 stroke gas engines.
The shark's 50 HP diesel is real close to the weight of my Honda 90...
 
Boris, interesting post. I did read a bit about the Yanmar outboard years ago. A guy from the Azores that I work with said he had seen one.

Like Steve says, one hurdle they have is the weight issue. They usually require a larger start battery as well which adds to the weight total. One other problem I see is availability of diesel. In Europe diesel is a lot more common, probably more than gas. In Canada not all marina's carry diesel. Larger diesel cruisers with greater tankage/range can source out marina's with diesel during their plotting. A small boat that would use this outboard may not have the tankage to cruise certain areas. I could see it working on a Rosborough, Ranger 21 or similar displacement cruiser.

Will be interesting to see how they work out.

Regards, Rob
 
Pat Anderson":3hnqfwvb said:
Aluminum engine? No thanks, been down that road once with a 1972 Chevy Vega!
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Why didn't you put a 350 in it like a lot of kids did back then?? :lol:

Aluminum blocks today use a cast sleeve in the cylinder. Much better! The Honda engines for example are bulletproof. We saw a lot of Accords coming through the dealership with over 500,000k on them and still running strong!

Rob
 
I recently read that Mooney Aircraft was putting a diesel plane into production, in China. I don't recall which engine was being used, but it sounds like they have solved the weight issue well enough to make it practical in a small single engine AC.
 
Very interesting Boris! I also have followed the Yanmar 27 and 36 hp diesel outboards--(every once and a while they crop up on Craig's list or E-Bay. Some were imported into Canada, and certainly more in the Caribbean. The US killer was emissions control. I expect that for even this latest generation emissions is going to be a deal killer for the US.

I agree that the 70 hp is close (26 lbs more) than the Honda 75 and 90. The motor has more torque--and probably can swing a bigger prop. A lot of unknowns, but I sure would love to try one out on the 22. I think it would be a good match. (We don't know the prop size, but it looks about 15". Apparently these are prototypes. Not yet in production.

The weight does not bother me, since I carry 3 group 31 batteries aft, and although it is a bit stern heavy, I can still run close to 30 mph with the rest of the boat light (do so yesterday).

The diesel must be some specific area of Canada--All of the "Great Loop" has diesel in abundance. All of the coasts of the US, have diesel, and some of the major lakes do also.

Diesel is about 30% more efficient, so you should have a longer range than gas engines. If push comes to shove, you might have to jerry jug some diesel….

I am not good at translating, but it appeared to me that the outboard is going to cost 25,000 Euro, and a gas engine 15,000 Euro. The cost break even point (fuel consumption?) is 1,000 hours. Beyond that the diesel wins.
As for torque, the 50 hp diesel engine has 60% more torque than a 60 hp gas engine.

As I understood, the information, there is a 50 hp and a 70 hp unit-about the same weight.

It would be interesting to put one on a C Dory...
 
Pat Anderson":2aa1sw30 said:
Aluminum engine? No thanks, been down that road once with a 1972 Chevy Vega!
Click to expand...

I thought the Vega was great. When I was younger I had two at once (a '72 and a '73). A friend had a Cogsworth Vega and the guys across the street had one they put a short block V8 in. IMO it was just the right size and with the rear seat folded down the back deck was completely flat and big enough from me to stretch out. I slept back there often.

The engine fit nicely in the engine compartment with plenty of room to work on it and change parts (not like today). You could change the starter by opening the hood and reaching in. Good luck with that nowadays.

Plus, you never had to change the oil, just replenish it.

The worst thing about it was that the lowest point on the car was the bottom of the oil pan. I cracked mine a couple of times bottoming the suspension (but it could be fixed nicely with JB Weld).
 
"Aluminum engine? No thanks, been down that road once with a 1972 Chevy Vega!"

Well, Pat, I once met a girl back in '75 who had a Vega. Right away, I knew both her and the car were to be avoided. Both were gonna be trouble. Chevvie doesn't do new stuff worth beans. The 350 engine is a bored out 283 that started in the 50's and they're still using that design. In the '90s they adopted hot rodder porting and called it some fancy name.

Although I had a neighbor who made money by welding up the head and block of the Vega engine so they didn't warp and reselling them. You could get them cheap, fix them and resell them. Turns out that the problem wasn't aluminum, but the design. And the Cosworth engines were something else.

As to the weight, please remember that diesels have a compression of 16:1. The lower end, block and head all have to withstand that. They're going to be designed stronger which means heavier. And they develop torque, not horsepower/rpm, so judge them by torque. Yes that means a bigger propeller.

And the diesel is thermally 30% more efficient than an gas engine, so it gets 30% more work done for the fuel. That's due to the compression ratio and that's why they exist.

And one last thought. Up in Canada this year we didn't meet a marina that didn't have diesel. And when we went to Alaska in 2000 we did meet a few marinas that didn't have gas since the local populace didn't use it. Fortunately our sailboat had a good Kubota/Universal diesel.

Boris
 
journey on":2e95gp7n said:
[ when we went to Alaska in 2000 we did meet a few marinas that didn't have gas since the local populace didn't use it.

Boris
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A friend told me in the Azores diesel is used for everything, boats, cars, trucks, and homes. It is sold very cheap compared to gas. He said if you have a gas powered boat you must be rich!

Another question I am pondering - I understand diesels produce more torque at low rpms and because of this boats can swing a larger prop. How does this affect low speed control around the docks? Some diesel boats use a transmission which can vary the drive ratio. Some use a hydraulic drive which gives infinite control. But with any direct/mechanical single ratio drive, it would either be engaged or disengaged. With a larger pitch prop this would make its idle speed higher than its gas counterpart. I have observed poker run boats(running high pitch props) coming into port and even at idle their speed is fairly high. I suppose it would require a engage/disengage type approach to the docks. Without prop thrust though control is limited to the rudder effect of the lower unit.

Any thoughts?
Rob
 
Well, there's a lot of sailors (or ex-sailors) on the C-Brats, so there's undoubtedly a lot of opinions on low speed diesels. And of course, here's mine.

Our sailboat had a small diesel, 30 hp, 4 cyl. I didn't notice the idle speed being any faster than the Honda on the back of Journey On. They both sound like tractors at idle, the Honda just like the Oliver the folks had. And I assume that the diesel would be geared to give the prop the same thrust as the Honda 90 has, if that's a reasonable comparison.

What that gearing would be I don't know, but it wouldn't be direct drive. After all we're talking about an outboard and it has to have some gearing to turn the corner at the final drive, so one gets to set that ratio. The over simplified idea of the prop is to accelerate enough water to produce the required thrust, so one would balance prop size, pitch and rpm to give the required performance. My bet is that the performance would be similar to the comparable outboard, just at lower engine speed. Again, just an opinion.

I learned to maneuver the sailboat by shifting between forward and neutral at low speeds, which I didn't find as useful on the Honda, since a C-dory is lighter and doesn't have a keel. So my conclusion is that the main difference between the diesel and gas outboard is weight and fuel consumption. Performance would be similar.

Don't you like the look of two flywheels turning in opposite directions? Zero angular momentum.

Boris
 
Boris, thanks for the reply. I was thinking along the lines that a diesel on a sailboat is mainly used for low speeds - ie. going in and out of port or for fighting current, tides, etc. It would then be propped and geared with this in mind. On a planning hull like the C Dory most owners would want to prop it for its top speed at its rated rpm based on their normal load. Because of a diesels limited rpm range(compared to gas) this may result in a high pitch prop because of the torque available from the diesel. I was thinking that the opposite side of this coin would be a higher boat speed at idle. ???

Just thinking out loud here -I'm not against diesels!! Modern turbo diesels are light, powerful and clean compared to their ancestors. Higher rpm as well.

Docking control - with a small powerboat when you disengage the drive you are limited to the rudder effect of the lower leg. On a sailboat when you disengage the drive you still have the rudder which being of greater mass/area than the lower leg of an outboard continues to provide a better degree of steerage. Perhaps not as much because most inboards are designed to provide an accelerated flow of water past the rudder which increases steerage.

Not likely an option on an outboard but some diesel boats use a variable pitch prop where the blades can be turned on the hub(from the helm). I believe they can even be turned to provide reverse thrust. Apparently they are very expensive though. Never saw one myself.

Regards, Rob
 
Rob,
One of the best engines I owned (Barry Rietz also ordered one at the same time), was an 18 hp Sabb Diesel with controllable pitch prop. The engine ran all of the time (although there was a dog clutch, so the shaft could be stopped from the engine room). The 16" two blade prop, could go from full feathering (blades aligned for and aft for minimal resistance when sailing), in forward or reverse, to the point they were at right angle and the boat were not move foreword or aft. You could do amazing things with that engine. The prop pitch was controlled with a lever, and the speed with another lever. There was no reduction gear as I recollect. These were not extremely expensive in the late 70's.

I also owned a larger trawler with twin 3208 Cat diesels--very easy to maneuver, due to wide spaced counter rotating props. For lower speeds at times one would run on one engine, or kick them in and out of gear. You are correct that the rudders of this boat were small, and the flow of water over them gave the steering effect. With singles, you kick the stern around either way with forward, and walk it to the direction of counter rotation in reverse. When you get stern way on a single engine power boat, you then can give bursts forward, with rudder hard over to move the stern in that direction.

The biggest problem with maneuvering is the mid to large sport fishers which have from 500 on up HP and will only idle at 6 to 7 knots. There it is either a trolling valve, or kick in and out of gear.

Some of the modern light weight diesels will spool up to close to 4000 RPM, so they are not as low speed at that Sabb (about 1600 RPM top)--or the Ford or Perkins which were about 2200. My Cummins 8.3 L C series has best torque at 1500, although at times it will run as high as 2500 RPM.

I don't think that slow speed maneuvering with a diesel outboard will be a major issue. The diesel idle down well, and as you say better torque at the idle speed.
 
Our 72 Vega died, like every other stock Vega, precisely at 40,000 miles. We were on the Pennsylvania turnpike. Our next car was a 74 Subaru, and we never looked back!
 
Pat,

The Suburu ( or Pleiades, as it's called in the European culture,) is the official state car of Vermont. I can only assume that each family is required to have one.

Boris
 
As it should be! When you need reliability and TRACTION there is nothing like a Subaru!

journey on":2gt0xzvh said:
Pat,

The Suburu ( or Pleiades, as it's called in the European culture,) is the official state car of Vermont. I can only assume that each family is required to have one.

Boris
Click to expand...
 
Our fourth Subaru had failed head gaskets, but SOA did not cover head gasket replacement on our 2003 Outback that cost $1500 to fix, but did for the previous year. Our car was just out of warranty when both head gaskets failed. Subsequently, they mandated special coolant additive to maintain head gasket warranty even on 2003 models. Good cars, poor warranty.
 
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