Pros and Cons of Diesel

[rgranger]

I didn't want to hijack the recent thread on getting diesel smell out of cushions... but that thread did make me revisit an old question I've been pondering for some time.

Why are diesels so popular on coastal cruisers? I can see why you would want a diesel for a boat with an interior engine... gas fumes in a boat are disastrous. And I get why you don't want a motor hanging off your transom for a blue water vessel but But given the hassles associated with diesel, I can't really see the advantage of an interior engine on a coastal cruiser. So why do so many coastal cruising boats in the 30-ish' range have interior diesel engines.

If you mine the forum you can find post after post of people asking about what filter to use, and how many auxiliary filters should be in line, and how many spares should you carry. Or people struggling with diesel leaks, diesel smells, bleeding lines, growth in the tank or problems associated with "stirring" up the tank in heavy seas, the need to "polish" the tanks etc. Then you have fixed props vs. feathering props, zincs on the shaft, bent shafts, stuffing boxes and it seems like the list of things to worry about never ends.

I've never owned a diesel but they sound like a real PITA to me. Seems like a transom designed to take a 4-stroke, in the 9.9 to 25 HP range is a lot smarter option. Why don't boat designers make their boats that way? Get electric start with electric tilt and life is good. You have no more issues with diesel smells, growth in the tanks, feathering props etc. If you need to work on the O.B. you can take it off the boat, to work on. Or better yet, take it to someone. Repowering is a 20 min. job.

What am I missing? Why are diesels so popular on mid-sized coastal cruisers?

 

[Meriachee]

Because they are way easier to work on, and came with the boat?

 

[Justin_NSA]

Inboards in general or specifically diesels? You suggest that a transom mounted engine would be more practical.

 

[py26129]

I have had two diesels and, with minimal care they have been extremely fuel efficient and stone reliable. To boot. you never have to worry about the prop coming out of the water or drowning the engine

Cheers

Matt

 

[Meriachee]

Not to mention the inherent lack of ease with which diesel ignites vs the rather explosive nature of gas. You hear about diesel leaks, seepage and the like here, can you imagine how that story would play out with inboard gas engines, given the same leaks and seepage?

 

[dlochner]

Diesels are more reliable than gas engines.
Diesels are more efficient than gas engines.
Diesel mechanics are simple compared to gas engines, i.e., no electrical ignition issues.
Gas engines have their own fuel issues aside from safety.
Outboards on a 30+ cruising boat are inefficient, have gasoline storage issues, and put weight exactly where you don't want it.
Inboards can support a better alternator for battery charging.
Inboards can heat a hot water tank.
Inboards place the motor weight in a more desirable location, i.e., close to midship and low.

That's all I can think of off the top of my head. Others will not doubt have more reasons.

 

[LeslieTroyer]

You couldn't give me an outboard only sailboat > 22 feet. I've have taken waves over the transom that drowned my 9.9 outboard hanging from the transom. Happened 3 times trying to go through a narrow pass. Not exactly the safest place to loose forward motion.

Also a outboard is still gas and not the safest fuel around

Les

 

[rgranger]

Thanks all
You only see people post with problems...

 

[uncledom]

You can walk away from a diesel, come back 3 years later and turn the key. Clackety clack it starts right up.
Some diesels can be hand started with a crank. They're simple.

 

[Justin_NSA]

Besides,

 

[Johnb]

I had a 23 foot sailboat with a outboard and now a 37 foot one with an inboard. In an area like San Pablo Bay where steep 5 foot waves are common in summer the inboard can cruise effortlessly against conditions that the outboard would be hopeless in, mainly due to the propeller coming out the water.
When it comes down to having capability, when you need it nothing else will do.
Other than that, outboards are cheaper, easier to maintain and easier to repower. But you get what you pay for.

 

[Meriachee]

Besides,

There's something to be said for the sound of a screaming CBX1000 from the 80's, but I'd take the clatter of the little Westerbeke when it's happy any day.

 

[Justin_NSA]

There's something to be said for the sound of a screaming CBX1000 from the 80's, but I'd take the clatter of the little Westerbeke when it's happy any day.

Those 6 cylinders really made a unique sound!

 

[dlochner]

Thanks all
You only see people post with problems...

Yeah, folks will post about a nice sail especially early and late in the season, but they seldom post "The diesel started up great today!"

 

[Meriachee]

Yeah, folks will post about a nice sail especially early and late in the season, but they seldom post "The diesel started up great today!"

I think I did once, after swapping out a load of nice RotellaT and the little Westerbeke sounded extremely happy for it. While it's interesting that it regularly sounds like it's ready to throw a rod, it can't be good for the wear and tear department.

 

[Justin_NSA]

I replaced my mixing elbow with a stainless one and installed my Speadseal Life water pump cover over the off-season. She started right up with no leaks when we put her in last week!

 

[Skipper]

https://forums.sailboatowners.com/i...board-diesel-a-comprehensive-approach.105777/
From back when I had an outboard.
Now I love my 2cyl diesel. However, maintenance wise, drastically prefer the outboard.
Diesel:
Change the cutlass.
Repack stuffing box.
Open and close the seawater intake. And maintain the seacock.
Clean the water filter.
Clean the air filter.
Change the oil and filter.
Change coolant.
Change fuel filters - detailed process.
Change HE zinc.
Change trans fluid.
Change raw impeller.
Clean prop.
Change shaft zinc.
Plus risers, alternator brackets, injectors, belts, electrical, etc.

Outboard: remove from transom, take to Honda mechanic, pay $183 for annual maint. Replace on transom.

Also my Honda 9.9 was quiet, which is a mixed feeling because I adore the sound and cadence of the diesel.

 

[Meriachee]

I replaced my mixing elbow with a stainless one and installed my Speadseal Life water pump cover over the off-season. She started right up with no leaks when we put her in last week!

Was there a second, or third mortgage involved in that pump cover? dang those things are pricey!

 

[rgranger]

On the issue of the prop coming out of the water and swamping.

I once owned a Coronado 25. The Coronado 25 had a false transom (motor well). That really seems to me to be the best set of compromises. The fuel tank was stored in the motor well also, so... no fumes in the boat... when the motor was in the down position, the prop was well enough forward that it would have been really hard to bring it out of the water... and the motor was protected from following seas.

I just grabbed this image off of the internet so it is not my boat, but you can see the protected motor well here...

What @Skipper said really rings true for me. I pull my Honda 9.9, for the winter....bring it home, change the lower unit oil, upper unit oil and plugs and put it in my basement till spring. In the spring I put it back on and go sailing.

I get the "whatever floats your boat" philosophy and I do appreciate the pros of diesel you all have put forth.. but if boat designers intentionally built the boats with an outboard in mind, I would find that a better set of compromises for the mid-sized cruising boat.

I can imagine a walk off transom with an engine well that extends upwards and doubles as the helmsman's chair at wheel. With a power lift & tilt mount, you could raise the engine up into the well and tilt it out of the water. Easy peasy.

 

[Jim 5757]

FWIW I love our Universal M3-20 diesel. All of the items that Skipper has posted pertain to any inboard gas or diesel. And gas fumes smell.bad too.
We like going offshore from time to time but I'd never go out with an outboard.