Sub-30 Foot Sailboat Power

[Ex-Calif]

I am a fan of having a diesel engine but I think I have become a convert for sub-30 foot boats. A few years ago the diesel died in my boat (compression) the parts for the Yanmar would come to over $4,000 add labor and machine shop costs and any diesel engine overhaul pushes $10k+

The motor is only 10 hp but damn, I get an 80 amp alternator that I gotta have! But do I? If I am putting $10k into an arguably $10-$15k boat does that make sense? No. For many of us it's just a cranky, persnickty (ancient) $10k generator.

So I put a 5hp outboard on while I noodled this. 3 years later I am still noodling it but I had an aha moment. The 5hp Chinese engine turned out to be a POS and I installed a 15hp Yamaha. First off I get 5 more hp than the diesel and the boat goes like a scalded cat wide open (actually I haven't run it wide open it scares me - LOL) while at gentlemanly speeds it sips petrol.

The PITA is reaching over the transom to start it, shift gears and throttle it so I have rigged up extensions.

The engine bay is clean and spacious (storage and batteries) and there is no diesel smell or smoke in the salon.

So my epiphany and plan for any next sub 30 footer is a 15hp outboard with a 10amp generator, electric start and remote controls. All this kit still adds up to tons less than a diesel overhaul. You can also pull the engine up for more efficient sailing and do away with saildrives and shafts and all that BS. There is the issue of prop cavitation but proper planning can minimize this and even shaft boats can cavitate in crap conditions.

With two remote tank you can carry 50L of petrol for plenty of range although I would seal the locker and install a bilge blower for safety.

The engine bay space is now purposed for more house batteries and 3-400W of solar takes care of the charging. I would also consider buying a Honda 2000 for an aft locker. I reckon all this kit is still cheaper than 1 full professional diesel overhaul for a sub-30 foot boat.

Electric is interesting but it's not there yet for me.You have to have too much solar and too many batteries to get the same or less utility.

- 15hp electric start outboard & 10amp generator - $2500-$3000
- Remote control kit - $500(?)
- 400W solar - $800(?)
- Honda 2000 - $1200

$5,500 is just the parts bill for a Volvo MD2010 overhaul.

[brownoarsman]

Thanks for putting the math out there. As I've got a 28 foot Pearson with its original universal raw water cooled diesel going on 2,500 hours (and no thermostat as a PO installed a recirculating valve instead so it runs at an always cold 110 degrees), it's good to see that I'm not facing a massive expense! Till then, religious maintenance is probably best, and getting that temperature up.
What do you think of the weight of the outboard on the performance of the boat? Mine is very narrow beam and I can feel the tanks up front and the anchor dragging her bow down and inducing a bit of weather helm. Especially loaded with panels high up on the pushpit as I imagine you must be with 300 watts, have you noticed a difference in hobby horsing?


Sent from my iPhone using Cruisers Sailing Forum

[SkiprJohn]

Hi Ex,

You've done the math and gone a direction that suits your needs. I've owned and sailed a bunch of different boats and because of local conditions I'll just throw the old negatives at the outboard idea. The positive is cost.

It adds a lot of weight to the stern that you might balance by adding chain to the anchor locker but then you get hobby-horseing might effect the sailing characteristics of your design.

It is usually mounted to one side of the stern or the other so is close to immersion while on the opposite tack.

At my age it is really hard to raise and lower a 4-cycle and they don't like to be placed on the wrong side.

Where I sail if you go out the bay you get lots of times when if the engine is running the prop and cooling pick up tube are out of the water half the time.

There have been times when sailing fast that the engine even in the up position gets immersed by a wave that slaps us in the butt.

Stowing gas (petrol) is always a concern aboard a small vessel. It truly is a lot more flammable than a diesel.

So, I guess you can tell that if I had my druthers I really like the sound and smell of a diesel.

Can you buy an old rebuilt for less than the parts?

kindest regards,

[Jim Cate]

And then for those of us who sometimes run aground... I've never seen a stern-hung outboard that would generate much thrust in reverse. This could be a drawback to add to the list...

Jim

[Don C L]

One thing I loved about my boat (Columbia 29) when I got it was that it had never had an inboard. Yes the engine hanging off the stern has its weight and handling hassles, and it is unsightly, BUT, I completely agree that to have all the stuff outside is nicer. True, gas is not fun but stored securely in the lazarette is somewhat acceptable to me. As far as reverse when grounded, I am not sure many inboards would really fare much better. That is a case for the little anchor rowed out in the dinghy to pull it off. But I am going to raise it one more level soon. Oars! Now I know, but hold on. A friend a while back kind of challenged me to go engineless so it has stuck as an obsession. For the most part, if I am willing to accept being stuck with no wind once in a while, I just need to get into and out of anchorage and harbor when it is dead calm. No I will not be powering out of tight spots, or bad anchorages, so as in the old days, I have to be careful not to get into them in the first place. The gunwales on my boat are low enough to make this possible. I haven't tried it yet but it's high on the project list. Personally I can appreciate the opinion that if you have a boat that MUST have an inboard, the boat may be too big, too sluggish or both! There, now that should generate some controversy!

[Reefmagnet]

I've had both setups on sub 30 footers and both have their pros and cons. I had a 25 footer with a 9.9 four stroke Yamaha hi thrust. With remote controls and electric start, there was never a need to reach over the back of the transom for the motor. The reason many outboards do not have much reverse thrust (aside from throttle restriction/gear ratio) is because the exhaust gas exits the props hub and causes cavitation. The "high thrust" outboards have a lower revolving prop speed and the Yamaha, at least, has a prop design that deflects the exhaust gases to the front of the motor when the prop is engaged into reverse giving it good reverse thrust. I had a 27 footer that was outboard powered but I retrofitted a new 10 hp diesel inboard. This same 27 footer had a 15 hp 4 stroke outboard prior to that took it through half a circumnavigation.

For me, this is how I see it...

Outboard Pros and cons:
+ Cheap and easy to install
+ Can be removed from the boat for repairs and maintenance
+ Don't take up internal space and there's at least 3 thru hulls saved.
+ No stinky diesel fume or scum lines on the transom
+++ Don't have to dive to scrub the prop clean

- Low charging capacity (though fitting regular alternators to small outboards has been done by some in the past and somewhere, someplace someone may even make an adapter kit)
- Add weight to the transom when hung off the back. Enough that can cause structural issues if not done properly, but certainly does weigh the boat down and encourages hobby horsing.
- Suffer, from various degrees, to having the prop pop out of the water. The rougher it gets the more prop popping that will occur.
- Motoring range suffers due to approximately 30% higher consumption than diesel equivalents and limited fuel carrying options.
- On the water troubleshooting and maintenance is a pain in the neck.
- security issues for unattended vessels in remote locations (as in risk of the outboard being pinched).
- outboard exposed to damage when reversing into berth or when tilted up on mooring.

Inboard Pros and Cons
+ High charging capacity as standard.
+ Lower fuel consumption and more fuel storage options.
+ Easier access for trouble shooting and maintenance when on the water
+ Better location in the boat for ballast and weight distribution
+ Longer lifespan
+ "Big boat" feel about them and arguably more reliable

- Expensive
- Take up internal space
- Add heat to the cabin
- Older units can add fuel and oil stink to the cabin (although I haven't had this experience - touch wood!)
- Adds at least two more below waterline holes to the boat
--- Have to clean the prop if not in constant use

I'd have to say that these day's I'd really only want an inboard on a smaller sailboat if I was doing extended long distance cruising. Other than that, the outboard has definite advantages.

[Ex-Calif]

Just a reminder that over 30 feet I think this is not the way to go. You can't really get more than say a 20hp on the transom effectively so when you pass 30 feet I think a modern diesel is the way to go.

Also many transom types (angled) make this a non-starter. Plumb transom is required, IMO, although I did consider a midships mounted outboard with a well and retractor. Some designs are doing this. You lose the advantage of creating inner space and you have a gas powered engine in the "salon" area - not my druther.

Originally Posted by brownoarsman

What do you think of the weight of the outboard on the performance of the boat? Mine is very narrow beam and I can feel the tanks up front and the anchor dragging her bow down and inducing a bit of weather helm. Especially loaded with panels high up on the pushpit as I imagine you must be with 300 watts, have you noticed a difference in hobby horsing?


Sent from my iPhone using Cruisers Sailing Forum

Weight and location matters on a sailboat. We want the heavy stuff low and amidships in general and we want a balanced boat.

The MD2010 weighs 280 lbs with saildrive. The Yamaha 15L weighs 90.

Using the bow as a datum the MD is at about 20 feet from the bow the Yamaha is 27 feet.

MD = 280 X 20 = 5600 foot pounds
YH = 90 X 27 = 2430 foot pounds

Mathematically the hobby horsing concern is a non-issue unless one is worried about a "light stern" - this may in fact be the issue with some of the extreme cases of cavitation. The stern lifts to easily.

In fact I wsa commenting to my brother how high Relax Lah! appears to be sitting on her lines after refit.

When one loads out the original engine bay with batteries one can actually balance the boat again I am sure.

Originally Posted by SkiprJohn

Hi Ex,

You've done the math and gone a direction that suits your needs. I've owned and sailed a bunch of different boats and because of local conditions I'll just throw the old negatives at the outboard idea. The positive is cost.

It adds a lot of weight to the stern that you might balance by adding chain to the anchor locker but then you get hobby-horseing might effect the sailing characteristics of your design.

See above I think we may have been thinking about the cause of hobby horsing incorrectly for quite a while.

Originally Posted by SkiprJohn

It is usually mounted to one side of the stern or the other so is close to immersion while on the opposite tack.

At my age it is really hard to raise and lower a 4-cycle and they don't like to be placed on the wrong side.

Where I sail if you go out the bay you get lots of times when if the engine is running the prop and cooling pick up tube are out of the water half the time.

There have been times when sailing fast that the engine even in the up position gets immersed by a wave that slaps us in the butt.

I think this can be improved. I have an "articulating" mount and yes the 88 pound deadlift is not fun. The vertical slide mounts are a better option and I bet some enterprising engineer could create a rack a pinion one with a crank or even electric motor!

Getting splashed, pooped whatever is of course a probability. I reckon a marine outboard engine oughtta be able to survive getting soaked but your concern is valid and real.

Originally Posted by SkiprJohn

Stowing gas (petrol) is always a concern aboard a small vessel. It truly is a lot more flammable than a diesel.

So, I guess you can tell that if I had my druthers I really like the sound and smell of a diesel.

Can you buy an old rebuilt for less than the parts?

kindest regards,

Petrol on-board is a concern for millions of power boats. They don't seem to blow up every day and most cruisers have petrol for the dink on-board somewhere anyway. One could even install a proper petrol fuel bladder, bilge blower etc.

OTOH - small generator (H2000) dink and outboard would all run on the same fuel and you eliminate one type.

The used Diesel of course is an option but you then still get 20-30 year old design and systems. Half the threads on CF Engineering would disappear if pesky, cranky, ancient diesel not working threads didn't keep us in business.

For $5,500 you get brand new everything...

Originally Posted by Jim Cate

And then for those of us who sometimes run aground... I've never seen a stern-hung outboard that would generate much thrust in reverse. This could be a drawback to add to the list...

Jim

True reverse performance is diminished. As you know there are other ways to unground - kedging, heeling, dink push and waiting...

[Don C L]

It sounds to me like you have nailed the defense of the outboard for the sub-30s. I could agree it may depend on hull design, displacement and cruising plans/cruising ground and personal preferences. I can only add that I may not be so satisfied with mine were it not for the set-up built by the former owner who was an engineer. It is centered on the transom and it is easily lifted clear of the water without having to tilt up the engine. It also has been lowering the long shaft plenty deep. I'll add a couple shots of it here. On some hulls I can see how the height of the transom and angle could make a transom-hung engine not desirable. In my old Columbia 24 I had the engine in a well and was able to tilt it up into a cut-out in the transom. It worked very well and the boat was not structurally compromised by that. The 29's engine well was designed to fit a Seagull engine which is way too small. As far as fuel for the outboard, what have you heard about the propane powered Lehr outboard? If I had the money, I'd seriously consider it. One review of it sounded positive.

[roland stockham]

Also had both and would say yes to the outboard with two provisos.
1 Coastal & sheltered waters only. Not suitable for big seas
2 Boats are measured by the ton not length '30ft is irrelevant' limit for me would be around 2 - 2.5 ton regardless of length.

Rather have a good outboard than a bad inboard though!

[Hard Rock Candy]

My first sailboat ran a 5 horse honda outboard with an accessory 7 amp alternator. Only once were we in trouble because of the outboard. In the bay of Honduras we got caught in a storm where we had waves so high that we could not keep the outboard in the water or unsub merged. we were gradually being driven ashore and finally dropped anchor in 30 ft of water. we only had about 110 ft of road and only ten ft of chain so it took a while to get the anchor to set. I know that outboard went under water about ten or 15 times, but it never did quit running. But little miracles happen a lot when at sea. Mac

[Rough Magic]

In the short run, the outboard is cheaper. But in the long run, the diesel is the less expensive choice.

Out board and parts, $4000, and a life of 2000 hours in the most perfect of conditions. A resale of 1/4 the cost. Roughly $2/hour over the life of the engine.

Diesel, $9000 (with new gear box), and a life of 10,000 hours with proper maintainance. A resale value in the boat of about half. Roughly 90 cents an hour over the life of the engine.

The real costs also have to take in the cost of the fuel. Diesels are at least 25% more efficient than gasoline. On a big power boat, this makes all the difference, not so much with sailors. It can even mean that at about 500 hours, the difference in fuel costs alone paid for the more expensive engine.

Safty: on inboard gas engines, the fuel tank is vented to the atmosphere, outside the hull. I would NEVER put a portable gas can in the hull of the boat, gas or diesel powered. If it leaks..... The USCG will make you remove it, if inspected. Your insurance may not cover you if there were to be a fire. You could build a sealed locker vented only overboard, to stow the gas can.

Each to his own, but my money, if only for safty, would be on the diesel.

Dave

[s/vfootloose]

I used to sail on a Seaforth 24 back in the late 70's It had either a diesel or a outboard that was set in a well in the cockpit. It was a great set up for an outboard.

[ramblinrod]

The best engine is one that is reliable and someone else pays for.


In the case of a slipped boat (any size) intended for cruising big water, I prefer a diesel for the reliable performance.


In the case of a trailerable boat, I prefer an outboard (for the weight savings and maintenance ease).


My son just went through some soul searching, while hunting for a 26 or 27 foot sailboat, intended to be slipped for cruising on Lake Ontario.


I advised to get one with a (good) diesel, and he did.


As long as the diesel runs, it will be the best choice. Should he need to repower down the road, he'll have to do some sole searching.

[warrior 90]

Originally Posted by Reefmagnet

I've had both setups on sub 30 footers and both have their pros and cons. I had a 25 footer with a 9.9 four stroke Yamaha hi thrust. With remote controls and electric start, there was never a need to reach over the back of the transom for the motor. The reason many outboards do not have much reverse thrust (aside from throttle restriction/gear ratio) is because the exhaust gas exits the props hub and causes cavitation. The "high thrust" outboards have a lower revolving prop speed and the Yamaha, at least, has a prop design that deflects the exhaust gases to the front of the motor when the prop is engaged into reverse giving it good reverse thrust. I had a 27 footer that was outboard powered but I retrofitted a new 10 hp diesel inboard. This same 27 footer had a 15 hp 4 stroke outboard prior to that took it through half a circumnavigation.

For me, this is how I see it...

Outboard Pros and cons:
+ Cheap and easy to install
+ Can be removed from the boat for repairs and maintenance
+ Don't take up internal space and there's at least 3 thru hulls saved.
+ No stinky diesel fume or scum lines on the transom
+++ Don't have to dive to scrub the prop clean

- Low charging capacity (though fitting regular alternators to small outboards has been done by some in the past and somewhere, someplace someone may even make an adapter kit)
- Add weight to the transom when hung off the back. Enough that can cause structural issues if not done properly, but certainly does weigh the boat down and encourages hobby horsing.
- Suffer, from various degrees, to having the prop pop out of the water. The rougher it gets the more prop popping that will occur.
- Motoring range suffers due to approximately 30% higher consumption than diesel equivalents and limited fuel carrying options.
- On the water troubleshooting and maintenance is a pain in the neck.
- security issues for unattended vessels in remote locations (as in risk of the outboard being pinched).
- outboard exposed to damage when reversing into berth or when tilted up on mooring.

Inboard Pros and Cons
+ High charging capacity as standard.
+ Lower fuel consumption and more fuel storage options.
+ Easier access for trouble shooting and maintenance when on the water
+ Better location in the boat for ballast and weight distribution
+ Longer lifespan
+ "Big boat" feel about them and arguably more reliable

- Expensive
- Take up internal space
- Add heat to the cabin
- Older units can add fuel and oil stink to the cabin (although I haven't had this experience - touch wood!)
- Adds at least two more below waterline holes to the boat
--- Have to clean the prop if not in constant use

I'd have to say that these day's I'd really only want an inboard on a smaller sailboat if I was doing extended long distance cruising. Other than that, the outboard has definite advantages.

Yes there are pros and cons
Check on Diesel outboards....yes the are not common but have
+ more compression = more power specially low RPM
+ lot less fuel consumption
+ lot less maintanace...no ignition system

- a little bit more noise
- also slightly more weight
- not too many alternatives of supply spare parts

Here is a Yanmar D28

https://www.youtube.com/watch?v=8kFj9aG9Eow

Yanmar D18

https://www.youtube.com/watch?v=3YZlJRpN-Eo

Parsun 15

https://www.youtube.com/watch?v=8At-PW0K784

Well, before You all think chinese crap look a little to the comentaries of the videos
Those are cheap options and unequaled in fuel consumption so less tank size or more range
No direct experience but those engines are running in a lot of boats

This also seems to be a possible cheaper solution for inboard on smaller boats.They have a 20 Hp 2 cylinder V Diesel 4 Stroke water cooled marine pack with gear box Total 80 kg
Runsun Products - diesel outboard motor manufacturer,40hp diesel outboard engine,v twin engine,10hp diesel engine,20hp diesel engine,v2 motor,diesel motor,v twin motor,small diesel engine,6hp small diesel engine,diesel generators,portable fire pump,w

Small foot print
Says very good for narrow hulls and short motor drive
Cheap Diesel Motors

[Ex-Calif]

I bought the Parsun 5hp. It is the engine I recently replaced with the Yamaha. Lasted 3 years. It was a model after the western management took over and things were supposed to be better. The metal parts were crap. All the shift linkage in the leg broke and then when I tried to repair started disintegrating.

One guy's bad experience.