Am I nuts to ditch the diesel for an outboard?

[coreywoodworking]

I have a 28' fin keel sloop with a 1984 Yanmar 2GM raw-water diesel that works well, and we're becoming friends. But I plan extended sailing south and worry about the expense of all the diesel-related parts. I sail on a shoestring and do all my own work.

Two of the five keelboats I've had used four-stroke outboards and I loved 'em. Simple, reliable, they control cost exposure and take up less space. I'd create a watertight engine well below the cockpit sole -- I'm very good with marine ply and epoxy. I plan to use a Yamaha 9.9 with a high-thrust prop, and remote shifter. I'd bolt the anti-cavitation to the engine well cutout, fit to a flange, to maintain hull shape. BTW, I'm not doing the Arnesen saildrive due to both expense and ability to hoist it out for service.

I'd appreciate lots of rational, thoughtful advice, but please don't wig out on me just because I think differently. It's why I'm asking for your ideas.

Other questions: Should the propellor be just aft of the keel, or in the prop's current spot, just fore of the rudder? Would the engine zincs corrode any faster than normal? Should the prop extend farther below the hull than normal tip clearance? Any questions I haven't thought of?

And thanks in advance, to the Sailnet community, for your guidance.

[bljones]

Your diesel is one of the most reliable diesels on the market, and it is easier to repair, cheaper to run, and more durable than any O/B ever built. Period.
Keep the valves adjusted, the oil and fuel clean and you'll have no problems.
Get yourself a spare parts kit from Torresen and go.

[sailingdog]

I think you're nuts for ditching a diesel that is in good working order. A diesel is a simpler beast than a four-stroke gasoline engine, and it gives you far more options—like a high-output alternator, engine-based hydronic heat, hot water, etc.—than an outboard. It also keeps the boat better balanced and is a much more reliable source of motive power in heavy seas.

Diesel is also a far safer fuel than gasoline.

One issue you also may run into with the Yamaha 9.9 in a well is getting the engine sufficient air to operate, especially near full throttle.

The advantage of having the prop just forward of the rudder is the flow the prop creates over the rudder's surface can help with steering, especially at low speeds.

BTW, I'll point out that getting a prop that is properly designed for a displacement monohull sailboat for your 9.9 Yamaha outboard may be fairly difficult to do. Most outboards do not have a prop that is sufficiently large diameter and shallow pitch to work well for a displacement sailboat, especially given the gear-ratio of the outboard's transmission. This is definitely something to consider before committing to going to an outboard.

[Sabreman]

Yanmar is probably the most popular diesel and parts are readily available and relatively inexpensive. In practice, unless you're traveling to really remote places there are few parts that are needed beyond spare belts, hoses, impellers, filters, and perhaps spare water pumps. Diesels are so reliable and IMO, more reliable than outboards. I'd seriously hesitate to scrap a working diesel for an outboard that will not drive the boat properly in a serious seaway. The diesel prop is so much deeper that it will always have bite whereas an outboard will have problems in a seaway, even if it's in a well.

Just my $0.02, but I wouldn't do it unless the diesel was dead and could not be repaired. Thinking different is good, my answer addresses the practical aspects.

[jrd22]

Taking a good running diesel out and replacing with a gas outboard will decrease reliability and increase onboard fire danger and fuel consumption will probably go up overall and the value of your boat will plummet. Combined with the huge amount of work you are talking about I just don't see the logic. Sorry, just my opinion. You shouldn't be intimidated by a diesel, they are pretty basic and very long lived. If you are at all handy, and it sounds like you are, you can do all the repairs that you will probably ever need to do on that engine. If you are concerned with it's condition, pull it out and for the cost you are talking about putting into an outboard and related modifications you could probably have it rebuilt and it would last you a lifetime. Good luck with whatever you decide.

Edit: sorry for basically repeating all the posts above, they must be faster typers than I am :-))

[Sabreman]

Unanimous. Don't do it.

[imagine2frolic]

Soak in the good information already typed above........i2f

[tommays]

Well

The outboards water pump would be a PITA to service if you mount it like that

Outboards do Not do well when submerged full time as you will get marine life in the water passages

[Izzy1414]

Corey,

I can't add much to what's been said already. I agree with them wholeheartedly. You sound like a pretty self sufficient type of guy. If you're worried about the engine, take about half the time and money you would budget for the modifications you are planning and pull the Yanmar and rebuild it yourself. In the process you will not only learn a lot about the engine, which will help if you ever have to troubleshoot and make emergency repairs, you'll also gain confidence in an engine that will be far superior to the outboard you'd be changing to. As far as the expense of repairs in remote locations ..... If you're somewhere you can't find parts or repair facilities for the Yanmar, I think you'll have the same problem with your outboard .... and it'll happen more often with the outboard.

[Faster]

Am I nuts to ditch the (working) diesel for an outboard?

... yes!