inboard vs outboard

[joeray]

I have just purchased for repair and refitting a Kingfisher 26 MK II yacht. It is fitted with a Lister Petter inboard which will need a good (and probably expensive) service at some stage. The engine is very large (and I assume, noisy) and takes up a large space in the cabin and sits literally in front of the galley. I am thinking of taking it out and replacing it with a +/- 10HP 4 stroke petrol outboard. Questions:

1. Does it make sense?
2. Will it alter the trim and hence the manoeuvrability of the boat?
3. Is replacing inboard for outboard aesthetic or does it go against all the tenets of good sailing practice - I don't want to offend!

Thanks in advance for any advice you may want to give.

Regards


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[Talbot]

There are three specific disadvantages to moving from an inboard to an outboard:
Engine performance in bad weather will be a lot worse, cause of the propellor coming out of the water (due to its position) .
Outboards have very poor electrical generation capacity.
You will need to carry a LOT more fuel, and this will be petrol not diesel.


If you really must change, the the only engine type that you should be considering is the high thrust range (designed to push sailing boats rather than high speed tenders) A good example is the <A target="_blank" HREF=http://www.yamaha-motor.co.uk/products/marine/outboards/Outboards_comparison_details.jsp?model=tcm:46-16861&model=tcm:46-16872&model=tcm:46-16883&model=tcm:46-16886>Yamaha FT9.9</A> Note the different gear ratio, and it also spins a more heavily bladed prop - so more thrust.

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[Vara]

I hadn't heard of this boat so I googled it <A target="_blank" HREF=http://www.boatsandoutboards.co.uk/view/CBB017/>Here</A>.
A broker with a sense of humour?

I would go for the inboard option every time, any Int combustion engine will give you grief and cost shed loads of money,but an inboard does give you better options regarding battery charging ,hot water,and would probably have better fuel economy,it also puts the propellor in the right place ie in the water.Your point about having a large weight is valid, much better to have a heavy lump in the middle or thereabouts than hanging off the end.

<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!

 

[LORDNELSON]

There are also advantages to the outboard outboard option. 1. Reduction in number of holes in the hull and worry about the stern gland. 2. Easy access for O&M. 3.In the winter no worries about freezing damage, you can take the O/B home!

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[doug748]

Also, really huge bills are impossible for the outboard, you just fork out 500 quid for a replacement. Ken Endean ( see Yachting Monthly) does more sailing than most and he seems happy with an outboard.
However you have a steady performer there and the extra push of an inboard might suit it better. I would only be happy with an outboard mounted in a proper well. Brian.

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[pc_eye]

Try looking at the Bukh-Farymann Diesel model 32W 8,2KW @ 3000 rpm = 13 HP. Weight 92KG marine engine seen at http://www.farymann.de/frames_englisch.htm this would be ideal for a 26 ft boat.

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[kilkerr1]

Hi

Welcome to Kingfisherdom! What sail number you got? We've had a K20+ for just over a year now and have just bought a K30 as a project. Just needed a K26 to complete the set...anyway another really good place to ask your question would be the Kingfisher Yacht Owner's Association. There are currently a few technical probs with the website but you could contact Pete Johnson who is one of their (extremely helpful) technical guys and has has provided us with loads of invaluable advice. I've PMd you his contact email address.

Happy Kingfishering!

<hr width=100% size=1><A target="_blank" HREF=http://kilkerr.members.easyspace.com/santateresa_pics.htm>Santa Teresa and other t'ings</A>

 

[ridgy]

Have the engine thoroughly serviced and if the engineer says it's okay then stick with it.

I had a 6hp outboard on my old boat and while it was always reliable it was never a pleasure. Motoring in to any sort of sea was the devils work, two small waves on the trot and you were stopped, that little egg whisk of a propellor just doesn't do the business. You might think there wouldn't be a sea without wind but you don't have to be in Portland Race for the tide to kick up a bit of chop.

Also the high pitch (5000rpm vs 2500) whine for 30 miles drives you mad and refuelling with petrol at sea is something you can look forward to.

Life is considerably better now with an inboard diesel, if a £100 per year more expensive in servicing costs (though some of that is saved in fuel costs). I would never go back unless there was financially no option.

Also consider the effect on resale.


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[Birdseye]

Dont do it!

No outboard is as good as a diesel inboard except possibly for racing boats where weight matters. Diesels are more reliable, have much less dangerous fuel, and drive through a prop which isnt stuck at the end of the boat and doesnt pitch out of the water when you really need it in bad weather. Outboards can be nicked - whoever heard of someone pinching an inboard? Outboard corrode badly, even the best of them.

And your boat will be worth less with an outboard.

<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[TrueBlue]

I suppose it depends on how much motoring you intend to do, and indeed how much you plan on using the boat.

I always work on the principal if If it ain't broke --(etc). Lister and Petter small diesels were very "agricultural" by nature, taht is were designed to be simple and easy to service "by a blacksmith" (i.e. lump hammer) and are reasonably tolerant of abuse. All you realy need to do is to change the oil and filter "regularly". I would do it once a year. I have a single cylinder gen-set at home for emergencies and I don't suppose the previous owners ever changed the oil - but it still runs.

Yes, thet are noisy, yes, they emit clouds of smoke when starting, but they run "forever".

Parts are available - contact Marine Engine Services of Uxbridge.

If it's a Petter it may be collectable and have some value.

If it were me I'd be inclined not to rip it out as a priority - see hoe runs for a season. If you want the space, then consider a small modern diesel from Beta Marine - who may be able to supply you with a drop in relpacement if you give them the model number. They know all about Listers.

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Stop what you're doing and wait my signal

 

[charles_reed]

Not much

The only advantages an outboard has over an inboard are the ease of taking it off to be worked on at home and that you can use it for steering.

In terms of effective propulsion it's useless in any seaway, it gives you a desperately shorter range, it's noisier, x5 as expensive to run and about 1/3 the life for only 1/2 the price.

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[extravert]

Some real figures

Just a few of my experiences...

My first boat with its subsequent owner is still on its original outboard.The outboard is a 1981 model 7.5hp Honda. It has never had a major overhaul.

My second boat's 10hp Bukh died at age 14 and cost £5000 to replace. It became uneconomic to repair - spares required were over £2000.

My current 10hp Yamaha outboard costs £1200 if I were to replace it, the same price as a Bukh sail drive leg.

My Bukh driving a 2.8 tonne monohull gave 20mpg. I had a 180 mile range.

My Yamaha driving a 1.8 tonne tri gives 19mpg. This gives me a 190 mile range.

In 2007 marine diesel is likely to cost the same price as road diesel.

The largest part of motoring cost for a small boat with typical useage is replacing the engine when it dies.

These are not made up figures. These are real experiences of the 3 boats I have owned.


<hr width=100% size=1>Summer is what you expect - rain is what you get.

 

[Vara]

Re: Some real figures

Would I be right in saying that a multi hull pitches less than a mono hull.
If that is so the biggest problem of an out board(getting the prop to stay in the water) would disappear.

<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!

 

[duncan]

Re: Some real figures

yep - and they are more efficently driven for any given boat length hence the excellent fuel economy.

my singular experience of an OB on a yacht (Jaguar 25 I think it was) trying to make ground against wind and tide after a long crossing to Le Havre - we just couldn't make any ground at all - resulted in me refusing to set foot in similar for a passage ever again. However for a multihull it make much more sense.
For a monohull a diesel should be significantly more frugal at anything less than full throttle, and at a more acceptable noise level as already stated.
The safety one is always interesting, especially when you consider how many diesel craft carry a small plastic can of petrol for the dingy stowed(?)...........
A good quality OB suited to your needs, plus mods etc and removing the old engine won't come cheap so if you can get some reliable life back into the existing unit, or even swap it for a rebuit unit, I would have thought it worthwhile in the long run.

<hr width=100% size=1>madesco madidum ..../forums/images/icons/smile.gif

 

[oldharry]

Re: Some real figures

No. Multihulls tend to pitch more, not less. However, Outboards or drive legs work better on multis because they are not placed right at the end of the hull as they almost invariably are on a monohull, so the prop is much less likely to be lifted out of the water.

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[Birdseye]

Re: Some real figures

extravert is hardly fair in comparing a notoriously expensive engine, the bukh, with a cheap outboard.

I first had a boat powered by a Honda 8hp o/b. It was unreliable in practise (water in electrics, silted up waterways, fuel vapourisation) and corroded quite badly. fuel consumption wasnt too bad but hp for hp, carburettored petrol engines consume about 50% more fuel than injected diesels. mind you, unless you do a lot of motorsailing, fuel bills arent really an issue.

my yanmar 2gm diesel was replaced after 14 years with another 2gm as a precaution when going to the med. the cost was £1600 after an allowance for the old engine which the dealer then did up and re-sold. this did not include a new gearbox or alternator, but everything else. bit more realistic for a modern engine than £5k for a Bukh.



<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[charles_reed]

Unlucky you

someone always has to be the exception to prove the rule.

Perhaps you should have been more mechanically wise when you chose your boats.

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[charles_reed]

The majority

of multihulls, use either an outdrive leg or an outboard.

The alternative is an expensive and space-hungry twin engine installation.

Extravert's posting should be viewed in the spirit intended, to provoke discussion and air the minority view.

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[joeray]

Thanks for all the advice. It appears that the inboard option will prevail! I am looking at a Yanmar 2GM20F and am going to talk to a marine engineer in Newhaven at the weekend. I shall brace myself re the cost!

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[joeray]

Thanks for the reply. The general concensus appears to be that I stay with the inboard option. I am currently looking at a Yanmar 2GM20F at a local marine engineers in Newhaven. My requests for a good service on the Lister are meeting deaf ears and, to bequite honest, I think I would rather buy new,
Regards

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