Inboard Or Outboard?

[Saildriver44]

Hi, I'm new here but I'm in the market for a 36-42 foot sailboat. As I search I find most have an inboard Diesel engine of around 25-30 hp. But...the PDQ and a few others offer outboards located in wells. I have sailed a Seawind configured like this and it seemed ok. My question is....which is better? I am very mechanically inclined and I can work on either version knowing full well the inboard can be a knuckle buster at times. I'm looking at fuel burn, maintenance, longevity versus cost, etc. I also understand the implied advantages of diesel fuel regarding safety onboard, engine life and reliability. But....which one....I'm surfing for opinions and suggestions which I may not have come up with on my own. The overall boat is my first concern but power is a serious consideration. Thanks for any and all input.

[Greenhand]

It is going to be much easier to work on an inboard while underway.


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[Mark1977]

Any boat in the 38 to 42 range will have an inboard. If that is the size you want , there will be no choice.

[Mark1977]

Oops just seen this is in the multi-hull .....I'm out of here.....

[Saildriver44]

Thanks for the input. Duh? I just noticed I put 38 instead of 36. Yeah, the PDQ, etc have the outboards. I've kinda narrowed my choices to a Maxim 380 or the PDQ, Lagoon, or Prout. So that gives me inboard, sail drives or outboard. I thought about being able to pull the unit out of the water versus sail drives or inboards in the water all the time, etc. My price range is trying to stay under $170k. Single handed and first Caribbean, then who knows. I've read so many posts of the best boat, best buy, etc. I think I'm going cross eyed. I've found lots of turnkey boats in the price range so now it's whatever I haven't thought of. Input?

[valhalla360]

I wouldn't buy the idea that it's easier to work on an inboard in a seaway. They are typically buried in the hull at the back of a cabin. An outboard can typically be pulled up and worked on in the fresh air on deck. I know where I would rather be.

What sold us is we replaced the entire drivetrain for $5k including installation when we bought the boat. Cost out what just a new diesel engine is (let alone the transmission and the rest of the drive train) and you would have to burn a lot of fuel to make up the difference.

Advantages:
- Prop is completely out of the water so it doesn't slow you down while sailing and no need to clean growth off it or monkey around with folding props.
- Modern 4stroke EFI motors are quite and are closing in on the efficency of diesels.
- Anywhere there are small boats, there is an outboard mechanic around.
- You will probably have gas on board for the dingy motor anyway.
- Not sure about the PDQ setup but if the battery dies, a couple pulls and our motor is running.

We are quite happy with an outboard.

[Cotemar]

Inboard diesels is the way to go with a 30HP for a 36 footer to a 40hp in the 42footer.

A 36 footer with a 30hp will be a fast boat in the 7.5 + knot range burning 1/2 gallon per hour using one engine only. If running both engines then the fuel burn will be 1 gallon per hour at 9.5 knots.

You will need 3 blade folding props to get those numbers though. The engine will be at or around 2400 RPM

[smj]

Originally Posted by Cotemar

Inboard diesels is the way to go with a 30HP for a 36 footer to a 40hp in the 42footer.

A 36 footer with a 30hp will be a fast boat in the 7.5 + knot range burning 1/2 gallon per hour using one engine only. If running both engines then the fuel burn will be 1 gallon per hour at 9.5 knots.

You will need 3 blade folding props to get those number though. The enginewill be at or around 2400 RPM

Your probably right, the large diesel motor will give you a faster motoring speed at the cost of sailing performance. We are talking sailboats? In all honesty they both have their advantages and disadvantages.


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[Tony B]

When it comes to sailboats, the type of mechanical propulsion, even though important, would be near the bottom of the list of requirements. But that's just me.
Generally, the specific boat (make, model, year) pretty much does not have a choice of propulsion type. You want that boat, you take that motor with it.
With power boats, the choice with inboard engines including I/O is usually gas or diesel. Rarely do you have the choice of inboard or outboard.
The basic design includes stability and weight distribution and usually does not account for the extra weight extending from beyond the stern for an outboard unless it was specifically designed for outboards.

I have been on sailboats that had their original inboard engines die on them. The owner replaced them with outboards. Did they work? Yes. Did they work well? Definitely not in any kind of sea. Under the best of conditions, the noise from cavitation was very annoying.

[valhalla360]

Originally Posted by Cotemar

Inboard diesels is the way to go with a 30HP for a 36 footer to a 40hp in the 42footer.

A 36 footer with a 30hp will be a fast boat in the 7.5 + knot range burning 1/2 gallon per hour using one engine only. If running both engines then the fuel burn will be 1 gallon per hour at 9.5 knots.

You will need 3 blade folding props to get those numbers though. The engine will be at or around 2400 RPM

30hp per motor or combined? A pair of 30hp motors is probably overkill for a 36' boat.

So by saving 1/4 gal/hr over an equivilent outboard with similar speed performance how long does it take to pay for a pair of 3 blade folding props?

Running the numbers, the only reason I can think of for going diesel in this scenario is if you don't want any gasoline on the boat. A valid concern though with reasonable care, it shouldn't be a problem.

[Cotemar]

Originally Posted by valhalla360

30hp per motor or combined? A pair of 30hp motors is probably overkill for a 36' boat.

I used to think the same as you do. Until I got on a 36 foot sailing catamaran with two 20HP diesels. What a dog it was in any heavy wind and waves. You always had to motor with both 20 HP engines, ALWAYS.

With twin 30 HP you have a fast boat using just one engine, no matter what the wind and waves are. If your in 50+ knot head wind and waves, Its OK to start the 2nd engine.

Every sailboat with inboards should have folding props.

[nimblemotors]

I agree, pick the boat you like and you get the engine setup that comes with it. I would only add that an outboard is easier to replace and repair, so the older a boat is, the more likely you will have to replace and repair the engine.
When I bought an old speedboat, I only looked at those with outboards.

Originally Posted by Tony B

When it comes to sailboats, the type of mechanical propulsion, even though important, would be near the bottom of the list of requirements. But that's just me.
Generally, the specific boat (make, model, year) pretty much does not have a choice of propulsion type. You want that boat, you take that motor with it.
With power boats, the choice with inboard engines including I/O is usually gas or diesel. Rarely do you have the choice of inboard or outboard.
The basic design includes stability and weight distribution and usually does not account for the extra weight extending from beyond the stern for an outboard unless it was specifically designed for outboards.

I have been on sailboats that had their original inboard engines die on them. The owner replaced them with outboards. Did they work? Yes. Did they work well? Definitely not in any kind of sea. Under the best of conditions, the noise from cavitation was very annoying.

[valhalla360]

Originally Posted by Cotemar

I used to think the same as you do. Until I got on a 36 foot sailing catamaran with two 20HP diesels. What a dog it was in any heavy wind and waves. You always had to motor with both 20 HP engines, ALWAYS.

With twin 30 HP you have a fast boat using just one engine, no matter what the wind and waves are. If your in 50+ knot head wind and waves, Its OK to start the 2nd engine.

Every sailboat with inboards should have folding props.

We'll have to disagree on how much power is appropriate, we motor on a single 25hp and rarely go above 1/2 throttle unless really fighting a really strong wind or current, so I don't know why you would need to run two 20hp all the time.

Requiring folding props just makes that much more of a case for outboards as it will take many years of fuel savings to make up for a few thousand up front on folding props.

[Saildriver44]

Many great answers here. I hadn't thought of the years of cost recovery for folding props or the anode replacement or normal corrosion on anything dangling in the water. Fuel consumption is a minor concern. I think the 9.9 hp on the PDQ's run about half a gallon an hour per motor, right? So very nominal comparatively to the diesel. And the cavitation may be an issue. When you need to motor due to foul weather what are the drawbacks to the outboard in a well? Is the cavitation really a performance detriment to be concerned with?


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[Cotemar]

Picking the right sail boat with the right engines is sort of like having ice cream or onions.

The well powered engines are like delicious ice cream and will make you very happy all of the time.

The under powered engines are like onions and sometime no matter how good you are and how hard you try you will still be crying when the sheets hit the fan.