Inboard or outboard engine

[Wansworth]

One choice I have is either a small yacht with an inboard or another with an outboard.Having had various yachts with inboards there seem to be quite a lot of downsides which with age don’t get better.Amongst the problems are getting at filters and seals fuel tank drains and shaft connections in general getting at stuff in awkward places and the need for an engineer to come to the boat if required,whilst an outboard is all there to sea and can be taken to a shop if required.The downside ofthe outboard is it’s not so handy to start and use in maneuvering situations nor in a rough sea.Not being in anyway an engine fixer much to my shame I am leaning more towards an outboard on a 7 meter yacht

 

[Bobc]

Depends on the type of sailing you will be doing. If it's mainly in flat water and moderate winds, then the outboard option is probably the best for the reasons you state. The biggest downside with them is that they come out of the water in a choppy sea.

 

[fredrussell]

For the reason Bobc mentions above, the only outboard setup I would want would be a centrally positioned well in the cockpit in which the outboard can be raised and lowered with ease. They’re a damn nuisance on the transom.

 

[TSB240]

Have you considered the limited range and how you I tend to store large quantities of highly inflamable fuel if you want to extend it.

You potentially get a long walk to a petrol station for fuel in my cruising ground.

10 hp diesel uses about 1 litre an hour at 5 knots on a 7m yacht. 10hp petrol OB 5 litres an hour 2T possible slightly better 4T

It's a lot harder for a tea leaf to take away your means of propulsion if it is fixed inboard.

Not convinced yet?

 

[AngusMcDoon]

10 hp diesel uses about 1 litre an hour at 5 knots on a 7m yacht. 10hp petrol OB 5 litres an hour 2T possible slightly better 4T

I'm not entirely convinced by those numbers for four stroke engines. Having owned a 30' trimeringue for 20 years (but not now) with a modern 10hp 4 stroke outboard I would use 1.5 litres of petrol per hour at 5 knots in calm conditions. Getting fuel is not always easy but I learned where it was available.

 

[dunedin]

Have you considered the limited range and how you I tend to store large quantities of highly inflamable fuel if you want to extend it.

You potentially get a long walk to a petrol station for fuel in my cruising ground.

10 hp diesel uses about 1 litre an hour at 5 knots on a 7m yacht. 10hp petrol OB 5 litres an hour 2T possible slightly better 4T

It's a lot harder for a tea leaf to take away your means of propulsion if it is fixed inboard.

Not convinced yet?

Clearly if planning to motor for hours on long distances an inboard diesel is best.
But if buying a boat to potter about locally in fine weather, the motor may not be needed for long, just to get in and out of harbour, so fuel consumption is a very minor consideration.

 

[Ningaloo]

My first boat was an MG Spring (7.8m). Most I viewed had inboard diesels but a few had outboards.
My "mentor" at the time persuaded me to only consider the diesels, something I never regretted. My first season was mostly pottering in the East Solent but in the next two years I sailed between Brighton and Dartmouth with one channel crossing. I would not have wanted an outboard for those longer trips which inevitably involved some motoring.
As an aside, the channel crossing convinced me that the Spring was too small and tender for my needs and I upgraded to a 10m Beneteau.

 

[barkwright99]

It's not exactly scientific but my observations of my partner in the RNLI is that they tow in more vessels with outboards than inboards...
Like I said, just an observation which you can't draw conclusions on but it would spark me to look into the reliability of each.

 

[PMJD]

Our first boat was a Gibsea 26 with an 8 HP outboard and a 5 litre cannister for fuel. Our experience was that if we ran it for a while and then came into the lock on our home port it would die just as you wanted to put on reverse and stop crashing into a wall or other boats. Our second and third boats had inboard diesels and we never regretted dumping the outboard as our main propulsion. Less flammable fuel, more reliable, easy to service. Yes small boats sometimes are a bit awkward to get to all the parts. But you adapt. We do all regular servicing and fluids ourselves.

 

[wombat88]

I had a Jaguar 21 with outboard in a well. 8HP 'sail drive' Tohatsu pushed her along quite well. Using both rudder and outboard manoeuvrability could be quite impressive once you have worked out the knack.

But...
1 I was advised not leave the outboard immersed for weeks. So that involved lifting the engine and resting it on something
2 Security. Padlocks and chains etc. 'Oh put it in the cabin' they say...well, as you get older 8hp gets heavier and heavier.
3 Reversing. Outboards make pretty hopeless brakes. An inboard seems much more capable of stopping a boat.

I wouldn't go there again

 

[steve yates]

My mariner 6 pushes my 18foot boat along at 4-5 knots using about 1l an hour. Its never burned 5l an hour in its life.
I carry 4 5l cans to refill the 12l remote tank, Enough to motor for 24 hrs, which I’ll never do.

 

[mrming]

I had a First 235 with a 8hp Yamaha 4 stroke. There was a cut out in the transom which meant it was very low / lots of shaft in the water, but could be tilted up easily for sailing / on the mooring. It had remote controls for throttle / gears. Boat was raced and sometimes cruised, mostly in flat water. The boat sailed extremely well so we really only used the outboard as a true auxiliary to get us on and off moorings / in and out of marinas.

Pros:
- Take off / home for easy maintenance.
- Simple to maintain and fix.
- Relatively quiet.
- Pushed the easily driven hull at 6 knots with no issues.

Cons:
- Fuel used to sit in the carb and cause it to gum up, blocking the very narrow jet. Only a problem if left for a while.
- Even though it was mounted low, would cavitate in big waves.
- Poor range compared to a diesel.
- Low output from the alternator (7A I think) so not great for charging batteries.
- Not great for close quarters handling.

As has been said above, if daysailing in flattish water, an outboard on a small yacht works great. If you’re going any distance, inboard diesel is a better option imo.

 

[LONG_KEELER]

I started out with outboards in boats, moved to diesel engines and now back to outboards.

The big difference has been dependable 4 stroke engines with solid state reliable electrics and much improved mpg with much less noise. All have been in outboard wells rather than on the transom which I have never fancied. Weightwise, up to about 6hp is manageable, around 26kilos.

To power bigger boats needing 10hp or so , things are starting to get seriously heavy. Noise is still a problem though with outboard wells . They are very difficult to silence unlike inboards. Bigger engines with lower revs is the ideal. I leave them in the well all year after having applied the appropriate primer and antifouling. The prop is easy to clean. I would not use an outboard if a saildrive prop was not available (Large Mickey Mouse ears) for displacement boats.

I prefer the flexibility of outboards, I even carry a backup . It suits me but it's down to personal choice.

There is lots of data on props stopped/turning/feathering but very little data on no leg or prop at all. On longer trips, I have shipped the outboard and inserted the fairing. To be honest, I have never really noticed the speed difference. Perhaps the racing boys notice the difference.

 

[Topcat47]

I have found fixing problems with an inboard diesel at sea, very much easier than with outboards. Even changing spark plugs when bouncing about in a chop is no fun, and you can forget changing a water pump impeller until you reach land.

 

[Stemar]

I agree with the pros and cons of each mentioned above. There is one other consideration, which is where you're going to keep the boat. If trailing it home ever time, you may appreciate the lighter weight of the OB, plus the relative ease of taking it for a service. In a marina with good security, either would be fine, but on a mooring, an inboard will significantly improve the likelihood of it being there when you arrive for a sail.

I'd far rather have a reliable OB than an unreliable inboard, but all things being equal I'd have the diesel. There are exceptions, obviously, but in my limited experience, once a diesel has started, give it clean fuel and oil plus a good supply of cooling water and it'll just keep going. An aging outboard can be even more of a hateful thing than a stroppy diesel!

 

[seumask]

We had a Hunter delta 25 ft powered by a 8hp 2 stoke Yamaha twin ( lifting in a well in the port quaterlocker ) and crossed to Cherbourg and the chanel Islands. We could just do a full crossing ( 75NM) on around 40L of petrol. That was much i mproved when we repalced it with a 6 hp Tohatsu 4 stoke. Less noisy and much more fuel efficent.
In broad terms if there was enough wind to sail we sailed, if there was'nt enough wind motoring was relcutantly accepted. A 70 mile channel crossing was not expected to be engine the whole way and we would not set off if that was the forecast. Our longest motor was across Lyme bay from Brixham to Chapmans pool, about 55NM but with some tide assist aprox 45NM motoring with the Yamaha 2 stoke.
Realy liked the ease of maintenance and swapability, often in the harbour we only used the 3 hp used on the tender.

 

[Wansworth]

On a personal note I motored through the Brittany canal in a 27 footer .The seagull gave out in La Coruña so gave it to a fisherman in Cangas,now have it back after 30yeRs in the basement…..still not running?

 

[Birdseye]

One choice I have is either a small yacht with an inboard or another with an outboard.Having had various yachts with inboards there seem to be quite a lot of downsides which with age don’t get better.Amongst the problems are getting at filters and seals fuel tank drains and shaft connections in general getting at stuff in awkward places and the need for an engineer to come to the boat if required,whilst an outboard is all there to sea and can be taken to a shop if required.The downside ofthe outboard is it’s not so handy to start and use in maneuvering situations nor in a rough sea.Not being in anyway an engine fixer much to my shame I am leaning more towards an outboard on a 7 meter yacht

Had one once and never again. Issues:
1/ outboards are petrol so consumption is high and refuelling at sea is dodgy yet sometimes needed.
2/ a lot of outboards are stern mounted and so become less useful the greater the pitching
3/ a lot of OB are not central mounted so you can only motorsail on one tack
4/ above 5 hp outboards are heavy so the idea of lifting off and taking home gets less practical
5/ outboards arent much use for battery chargin
6/ outboards are raw water cooled and corrode / block as a result.
7/ sea water and ignition systems arent good bedfellows.
8/ outboards are nickable and attractive to low lifes

 

[LittleSister]

My take on it is that it depends on the type of sailing you aspire to. An outboard is fine in and out of the same place and, if it's transom mounted, without much in the way of waves and swell.

If you want to go cruising there's no substitute for a diesel inboard.

I say that as someone who used to cruise with a petrol outboard - an absolute pain in the neck. Many hours, miles walking and taxi fares (and tide/daylight/weather windows) wasted trying to get to petrol stations (not necessarily open once you get there!) in places I wasn't familiar with.

Some modern outboards might perhaps provide a decent electrical output, the pathetic output of mine was another serious constraint. Some modern outboards might be less outrageously thirsty than mine was, but even then I doubt you'll get near matching diesel fuel economy in real cruising, and carrying enough petrol can be a real constraint.

If you want to go cruising get a diesel inboard, learn some basic diesel and electrics maintenance if you're not already familiar, and select the boat carefully for general condition of the engine and availability of spares for that model.

 

[jamie N]

I've an inboard diesel and a 2.3 outboard on the back. I like the back up of having both, and find that within a marina the outboard is (by far) the better option. The outboard has had an extra 6" extension fitted to it, and is used on the inflatable at other times.
If I'd to only have the option of one, it'd be to have an inboard, pretty much every time.