Diesel Outboard ?

[trout888]

Has anyone had experience with the diesel outboard motors? Yanmar makes one as well as a couple of less well known companies. After failing to find an affordable Prout we are looking at a couple of gas outboard powered catamarans. We worry about the explosion factor of a lot of gas aboard. Are we correct in thinking that diesel would provide less chance of explosion?

[GordMay]

Diesel outboards will be big, heavy, expensive, and much safer than gasoline. They are generally only available in larger sizes (I think > 40HP).
Sorry, I don't have any practical experience /w them.
Regards,
Gord

[Jeff H]

Gordon,

I have to respectfully disagree with your statement, "Diesel outboards will be........much safer than gasoline". If you are comparing diesel outboards to gasoline outboards I would think that the difference in safety is pretty minimal in the typical multihull installation. In most cases, gas outboards used on Outboards are either out in the weather or in compartments that freely vent to the weather and are sealed from the interior of the boat. The gasoline fuel tank and fuel lines are generally contained in that compartment. I think that the relative explosion hazzard of a gasoline outboard compared to a diesel outboard in that application is comparatively small.

It is certainly a way smaller risk than using a propane stove which is actually more explosive than gasoline and which typically has the stove and propane piping within the interior of the boat in a boat that lacks bilge blowers and because they are diesels, lack the explosion proof electrical systems required on gasoline engines. It is certainly safer than storing the spare gasoline for the dinghy in an unvented locker which is something I have seen cruisers do a lot of times in my life.

Jeff

[Jeff H]

Nuts! If I could only type worth a darn. Please make that "gas outboards used on catamarrans" not "gas outboards used on Outboards"

Jeff

[GordMay]

GAS vs DIESEL (Safety)

I apologize for my (earlier) incomplete reply.

The safety, utility, (& etc) of any one component (engine) of a system (ie: propulsion), must be examined within the context of the entire system, and it’s environment (boat).

Due to the inherent hazards posed by Gasoline, these installations are burdened with (and benefit from) some very stringent standards (beyond those required for diesel systems); including (but not limited to):
- Flame arrestors
- Bilge & Engine Rm.Ventilation
- Ignition-Protected Electrical devices.
- Compartmental Separation
- etc...

Gasoline & Diesel systems are (should be) both designed & installed to be safe in use under most conceivable situations. Murphy’s Law is not repealed, merely because we’ve adhered to all of the regulations, standards, and recommended practices regarding our engine & fuel installation. Systems, and operating procedures can and do fail, and even our best laid plans often go awry. When enough of the safety features of a gas system fail - BOOM! Under similar circumstances, a diesel failure might more likely be untidy. . I don’t believe that the issue is (so much) the LIKELIHOOD of a safety failure, as the it is the CONSEQUENCES ... Diesel fuel, on it’s own, is much less volatile than Gasoline - hence inherently and ultimately safer.

It seems obvious that any specific installation must be surveyed for it’s adequacy as installed, and operated. It is conceivable that a particular diesel system might be less safe than a particular gasoline system. This scenario would have to compare a properly designed, installed, maintained, and operated gas system against a seriously inadequate diesel alternative.

I think that suggesting that the very stringent specifications required for gasoline installations, and their safe operation creates as safer condition than a (proper) diesel alternative is false - hence I’ll stand by my broad statement - Diesel is SAFER than Gas.

I’ve owned and operated both Gas (OMC Saildrive, Outboards) & Diesel (Yanmar & Cat’ inboard) engines, and offer the following recommendations for BOTH:

- Always use ignition protected electrical equipment within (or proximate to) the engine compartment, and battery box. Most good marine gear is so rated (but check).

- Always install & use an Engine Room/Bilge Exhaust fan, after refueling. Often the engine room also requires ventilation to provide adequate combustion air and for cooling.

- Never store any fuel (gas, diesel, propane, etc) in un-vented compartments, nor those open to the accommodations.

- Inspect & maintain your entire propulsion system regularly. This includes fuel, mechanical, accessory / ancillary gear, and exhaust. If using fume detectors, remember that diesel engines generate NO2, as well as the CO that both produce.

This reply remains incomplete - there are a huge number of issues that relate to the proper installation of the several fuel systems used on boats. See ABYC Standards (I could fax a copy to those requesting):
H-2 (Ventilation, Gas), H-24 & 25 (Gas fuel), H-32 (Ventilation, Diesel), H-33 (Diesel fuel), P-1 (Exhaust), P-4 (Engines), TH-23 (CO), A-1 (LPG), A-14 (Fume detection), A-24 (CO Detection)...

Having said all that - I’d rather have a PROPER gas boat, than none at all!

OMO
Respectfully but opinionated,
Gord

[tenknots]

Yanmar makes (or made) 2 different diesel outboards, both are, I believe, 3 cylinders. They are heavy, but very efficient, compared to gasoline outboards. They're also pretty noisy. Besides being expensive, service and parts for them in this country is nearly non-existant. There's just not very many of them.

I looked at a used one for my 30 boat and couldn't justify the 200+ pounds hanging off the stern, even after removing a non-functioning inboard diesel. Sure would be easy to work on though!

A gasoline outboard, in and of itself, is hardly more dangerous than a diesel outboard. The danger is in the storage, transportation and potential leaking of gasoline. In order to carry enough gas to actully get anywhere (maybe twice as much or more than a comparable diesel outboard), it probably is going to be stored in a compartment. Done right, it's safe. Done wrong, or not inspected often enough, and it might land you on a different island. Contrary to Jeff's posting, gasoline is more dangerous than propane in some ways. Gasoline vapors have a higher density than that of propane. Gasoline vapors, being heavier can spread faster. A gasoline-to-air ratio of as little as 1.4% to one is enough to cause an explosion - propane needs 2.1%. There are far fewer insurance claims for fires and explosions due to propane than gasoline.

That said, a carefully designed and maintained gas system is very safe, though more vigilance is required than for a diesel system.

For a multi-hull, it's hard to beat a lightweight 4 stroke gas engine, especially the "high torque" models made by Honda. Just know what you're dealing with.

[HYDROCAT]

Hi there is 10HP Diesel outboards availble from Goods Direct ltd,
they are manufactured in India and are called Star Outboards,
see OUTBOARDS DIRECT FROM CHINA PETROL AND DIESEL & MARINE EQUIPMENT SHIPPED WORLDWIDE for more details, thanks Stephen

Originally Posted by trout888

Has anyone had experience with the diesel outboard motors? Yanmar makes one as well as a couple of less well known companies. After failing to find an affordable Prout we are looking at a couple of gas outboard powered catamarans. We worry about the explosion factor of a lot of gas aboard. Are we correct in thinking that diesel would provide less chance of explosion?

[Alan Wheeler]

Yanmar had a 27Hp diesel. Very heavy and very big. Similar sizes in petrol outboards were ten times more powerful. The original Yanmar outboard was design for a specialised market. This was many of the long rivers in very poor countires like deepest darkest Africa etc. The yanmar may be small in power, but it's pushing power was remarkable. It was good for pushing very heavy loads, but not at a great speed. That was 18yrs ago now and it is possible that future models may have been introduced.

[never monday]

The one referenced in the link above is nothing more than a rip off of a Yanmar industrial air cooled engine on a platform/gear box assembly.

[HYDROCAT]

Dont think so, best you supply some proof with your opinion

[never monday]

Originally Posted by HYDROCAT

Dont think so, best you supply some proof with your opinion

When you learn that I know most things Yanmar your above statement will become unnecessary.

The proof
Yanmar L-series air cooled INDUSTRIAL engines 4-10hp. Used as power for pump, generators, go karts...where ever a gas Briggs can be used.



appologies are accepted on Tuesdays.

[never monday]

I find it interesting that outboards.cn is your homepage also.

How are you affiliated?

I am a dealer for many lines of marine and industrial engines. That's public knowledge.

[witzgall]

I had a Yanmar 27 hp diesel outboard on a 15ft RIB for about a year, around 1995. We were helping the distributor get the word out in the US. It was about the same weight, maybe a bit heavier than the 40hp 2 stroke it replaced. It was used hard for that time, and eventially, the drive casing cracked. I don't think it was the on the water that got it, but the engine was not supported properly during trailering, which was up and down the east coast of the US.

We replaced it with a 40hp 4 stroke Honda. The honda used about the same amount of fuel (for our use) as the Diesel, which was about 1/2 of what was used with the two-stroke. It was much quieter, and WAYYYYY faster (scary fast).

If I was a fisherman, or looking at a cruising boat application, I would consider the diesel. For any runabout or such, 4 stoke engines are much superior IMHO.

And Wheels, you are right, I htink that engine could have pushed a locomotive throught the water.

I think they pulled the sale of these in the US.

Chris

[never monday]

Originally Posted by witzgall

I think they pulled the sale of these in the US.

Chris

The EPA regulated the Yanmar outboards out of existence in the US

[HYDROCAT]

Sorry thought you meant the Gearbox and outboard leg,
any Engine can be attached with a adapter, they recomend just 10hp,

First time I sold a Zhongshen Diesel outboard from china 10hp diesel Outboard motor to a customer in INDIA, who saw them as great for their idnia diesel outboard engine market, they went to the boat show and displayed it its the photo of the unit with the red tank and Star on it,
when we went back to order them the Factorie says they stoped production,

So the indian Gentlemen saw alot of improvments and decided that they would supplie them, and also developed the power pole version,

Alot of people are interested and have 100s enquires each week,

they have supplied there first one just now, as attached,
a long shaft bottom end and gear box and it looks more robust,

Now I help them to find the buisness for their New production as part of Outboards.cn and Goods Direct Net

I own alot of domain names and are trying to keep upto date with products availble and be helpful, I also like to invent new boats and make barges and my latest project is a Amphibian truck,

Alot of ideas which become hard to make $ from, have to stick to paper for now,

Appreciate any feedback and facts, no offence meant,