outboard vs diesel inboard

[michaelmrc]

good day everyone
my wife and i are looking at purchasing our first saiboat we have found 2 virtually identical 1980 catalina 27 ft boats both in seemingly great shape. one has a 2005 9.9 4stroke yamaha the other a new yanmar 1gm diesel and transmission with only 80 hours. my question is this. is it worth it to spend the extra 3k on the boat with the diesel is this a good engine or should we be looking at outboard power. thoughts suggestions . thanks

[David M]

Do you anticipate motoring quite a bit? If so go with the diesel. The advantage to an outboard is that they are easily removable for major servicing, easier to access, weight less for a given horsepower, don't take up space that a diesel takes and cost less than a diesel.

Its been my own personal experience that fewer things go wrong with modern outboards than diesel engines. I think their operating costs, for a given horsepower, are lower as well. Especially for the lower horsepower engines. Diesels last longer but then it takes one heck of a lot of cruising to wear out a well maintained outboard....plus the replacement costs are lower for an outboard for a given horsepower.

Of course, gasoline is much more flammable than diesel. In heavy seas, an outboard might become unusable as the boat pitches. Diesels have real alternators for recharging the battery versus a magneto for an outboard which do not have the same charging capacity. 27 feet is sort of the outer limits for an outboard on a sailboat. Any larger and you would want an inboard engine.

Overall, unless the boat is going to get some heavy usage, go with the outboard.

[Pelagic]

It really depends on your area of cruising. If you are sailing in mostly protected waters then the seas wont bother the o/b and you have more useable space inside,
o/b is much easier to maintain and much quieter

[michaelmrc]

thanks everyone i understand that diesels would be more expensive to fix but if this boat has a brand new yanmar ( owner has receipt for $8000 ) then my thinking is that the diesel will last longer and be more efficient, as well it would have a better charging system than the outboard 65amp alternator vs 6 amp stator on the outboard. am i understanding this correctly? thanks

[SkiprJohn]

Aloha Michael,

Welcome to the forum of many opinions. First of all, I like the boat you have chosen.

The four stroke outboard weighs nearly as much as the Yanmar and is placed way aft which will make your boat squat and not perform to its potential. Gasoline aboard is never a good idea if you can avoid it. It is quite a bit more volatile than diesel. The Yanmar is way more dependable than the outboard and easy to work on. If you keep the fuel, oil and air clean then it will last longer than we will.
It is not worth 3K more. If you are using the motor (engine) to just get you in and out of a slip I'd get the one with the outboard, sell the big overweight outboard and get a largest Minn Kota electric 12v (you have a battery aboard already) or a small two stroke outboard and have lots of money left over. If you are doing a lot of motoring like in the intracoastal waterway then I'd go with the diesel but offer them less.
Kind regards,
JohnL

[David M]

You cant buy new two strokes any longer.

A 39 HP Yanmar 3JH4E diesel weighs 381 pounds not including the transmission. A 40 Hp Honda four-stroke weighs 212 pounds including the transmission. It is not true that the same horsepower diesels and outboards weigh even close to the same. I'm not meaning to be argumentative at all, I just wanted to make sure Michael got the right information.

Honda BF40 4-Stroke Marine Outboard Engine - 40 HP Motor Specs
Yanmar Marine

[jzk]

Originally Posted by David M

You cant buy new two strokes any longer.

Yes you can. They are legal in every state.

[David M]

Originally Posted by jzk

Yes you can. They are legal in every state.

I just called the Outboard Motor Shop in Oakland. You are correct with restrictions. Only two-stroke Tier Two outboards can be sold and there are no Tier two two-strokes below 40 horsepower right now. Next year there will be Tier Two two-stroke outboards available below 40 horsepower. This is for California at least. I'm pretty certain the Tier Two standards are federal law though.

It is the old type of two-strokes that send up clouds of blue smoke and leave a sheen of unburned oil and gas on the water that cannot be sold new. Those are the type that I was visualizing. Every drinking water reservoir that I have been to have banned these engines.

[michaelmrc]

well a new 2008 yamaha 9.9 4 stroke outboard weighs 95 lbs and the yanmar 1gm weighs 135lbs. by the time you factor in the weight of transom mounts etc i dont think that there would be too much difference.
fyi yamaha does still make a 2 stroke 2.5hp up to 25hp and mercury actually makes a 50 hp 2 stroke as well.

[Zach]

I like outboards.

If they blowup, need a tuneup or anything of great importance repaired you can pop them off the transom and work on them on a dry land, on the dock, or set them in the cockpit. Standing up with a work bench in air conditioning or heat is also a possibility! They never need the shaft packing replaced... and the amount of time standing on your head in the bilge is... none! (And the bilge water doesn't smell like a fermenting brew of diesel and oil drippings!) You can replace the whole fuel delivery system for a hundred bucks. Heck, you can have a complete spare fuel tank with priming bulb and filter that doubles up for use in the dinghy.

Three less holes in the hull, no raw water hoses to replace. No heat exchanger (unless you want to rot out the engine block...) No wet exhaust, mufflers, elbows... Throttle and shift linkage are mounted on the engine. No gauges, if somethings about to blow it gives the same warning of impending doom as a push lawn mower... Clattering, pinging, etc. (About as complex as one too...)

For a couple hundred dollars you can have a spare complete drive train, and for a thousand to two you can have anything brand spanking new from mild to wild.

Then when you get to the dock, theres no such thing as prop walk in reverse. You've got a directional stern thruster, and a boat that will spin on its axis. Under sail, hoist the prop up clear of the water and you are faster than the same boat dragging a prop. When you aren't using the boat, the zincs are clear of the water so nothing is getting corroded.

Downsides: The suck in any kind of steep chop, lifting the prop clear of the water. Good news is, if theres a steep chop theres normally wind to go along with it, just hope where you want to go isn't where its blowing from! They are noisy, and a theft target. If you want to motor sail, one tack does a little better than the other. They can be a pain in the rump to shift gears, pull the cord, and steering them can require some contortion...

I'd go with the outboard... Or buy the diesel, pull it out and sell it and all the components and then mount an outboard. It is a sailboat after all, might not look as pretty but no prop drag is mighty nice! I'd say if you are interested in sailing performance to count the pounds, put a light weight one on the stern get out to the channel... pull it off and lay it on the cabin sole.

My Triton came up out of the water 4 inches in the stern after I pulled the inboard engine. (With the outboard still hanging on the transom!) the prop, shaft, stuffing box, stringers, and bronze seacocks are still in place! Then theres the storage space...

[Talbot]

Having run for 14 years with a diesel outboard, I believe I have a good view on this. The major drawback for an outboard is the lack of charging capacity. Unless you intend always running from a marina, and thus have adequate re-charge capability - go for the inboard option.

Another factor for the inboard is that salt water and outboard mounts are not really very good bedfellows.

Finally - diesel consumption versus petrol.

for $3k it is no contest in my opinion.

[David M]

A gallon of Diesel can produce about 30% more mechanical energy than a gallon of Gasoline. It takes 25 percent more oil to produce a gallon of diesel though. We all know the prices of Gas versus Diesel in the States. Diesel is slightly more at most pumps than premium gas but at the gas dock, in my experience, varies radically. Sometimes gas is more, sometimes diesel is more.

So those are some things to consider here.

[Boracay]

I built a 6.5m Van Der Stadt plywood yacht some years ago.
The yacht had a wide stern and took a small outboard perfectly.

In the light conditions around Wewak in northern New Guinea it was wonderful.

I would only consider an outboard on a yacht if the expected winds were less than 15kts and the waters were sheltered.
Around Sydney (Oz) I have always used diesels.

There is a lovely warm feeling about chugging along with a diesel, especially a single cylinder.

[Artful Dodger]

The chance of a diesel over an outboard, I don't think has any doubt, the diesel is more dependable, and more value to your investment. There is the fact that you can put add ons on, thus enjoy a happier sailing experience. If it weren't so why do boats with diesels sell for more.

[nautical62]

When my inboard bit the dust on a 26-foot pocket cruiser, I decided to replace it with extra long shaft outboard instead, so I experienced both on the same boat. The boat was sailed on the Great Lakes, SE Florida and Bahamas.

Things I liked about the Outboard:

1. Much Cheaper (initial purchase price)
2. I could easily remove it from the boat for maintenance
3. The motor tiller could be turned in addition to the ships's tiller to provide very tight turning.
4. The boat batteries could be completely dead and I could easily pull start the engine to start producing power.
5. I didn't have to have my hands snaking through the bilge to work on it.
6. No stuffing box or intake related thru hulls, so there is less danger of sinking the boat.
7. I used a common fuel for both main engine and dingy motor
8. I could get gas at any gas station, or simply load the external tanks in the dingy to go to a dingy dock when anchored, without the need to pull the big boat up to the dingy dock.
9. Freed up more space in a small boat for storage.
10. Outboard weighed notably less (raised the water line a couple inches)
11 Fuel system is external, so less danger in some ways
12. No diesel fumes inside

Negatives: (Or advantages I experienced with an inboard)

1. Inboard is likely to last much longer
2. Inboard is likely to have less maintenance
3. Inboard will most surely have a larger generator and produce more power
4. Nobody is going to steal your inboard off the back of your boat when you are not looking
5. Less danger of prop coming out of the water or plunging head into the water
6. Usually they are diesel fuel which is less volatile (but, it's internal)
7. Likely to have a longer cruising range between gas fill ups
8. Engine controls will most likely be located in a good location.
9. An outboard, being external, is more prone to damage.


I'm now back to having an inboard on a different boat, and prefer it overall, mostly because of it's ability to perform in steeper seas. Energy output reduced stress about performance or maintenance are also really important changes for me. As I begin to look at 30-foot boats for ocean sailing. I'm only considering inboard diesel engines. However, if I was looking at 26-27 footer for inland trailer sailing on protected waters, I'd probably go with an outboard.