One engine or Two?

Corky

Corky

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I'm looking at 2 boats currently, one is a 2002 model with a single diesel engine 250hp with bowthruster, the other is a twin engined (AD31s) 1994 model with no bow thruster. Both are same model, similarly priced ( yet to be haggled) and both nice boats. The question, I suppose is, knowing there are pros and cons of two vs one engine - has anyone gone from a 2 engine setup down to one and was it a problem?
 
Corky said:
I'm looking at 2 boats currently, one is a 2002 model with a single diesel engine 250hp with bowthruster, the other is a twin engined (AD31s) 1994 model with no bow thruster. Both are same model, similarly priced ( yet to be haggled) and both nice boats. The question, I suppose is, knowing there are pros and cons of two vs one engine - has anyone gone from a 2 engine setup down to one and was it a problem?
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I haven't gone from 2 engines to 1 but until recently I had a single sterndrive engined 25ft RIB for messing about in the Solent. To be honest, I'd got too used to the easy handling of twin engined boats and handling a single engined boat, even a small one like mine, in a confined marina came as a bit of a shock at first. I got used to it quite quickly with a bit of practice but it was a good thing that it was a bouncy inflatable boat rather than hard grp
All things being equal, I'd always go for twins, from the safety point of view as well as the easier handling but I've had AD31's in a previous boat and they're noisy vibey things so sea trial the boat first before you commit
 
It would be two engines every time, however, the other question is; do you want a 1994 boat or a 2002 boat, surely there is a big difference in the general appearance, the 2002 must have a contemporary modern finish with up to date equipment and materials, whilst the 1994 must look dated
 
single or twin!!

Hi
I have done it the other way,ie from 1 to 2,i never had a problem mooring with only 1 & 2 are alot more expensive to maintain,& alot more in the water to hit things with,regards MM1. ps.forgot to say my choice would be 1.
 
Tidnock said:
It would be two engines every time, however, the other question is; do you want a 1994 boat or a 2002 boat, surely there is a big difference in the general appearance, the 2002 must have a contemporary modern finish with up to date equipment and materials, whilst the 1994 must look dated
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Doh! I missed that. That would change things for me. If it's the same boat at the same price but 8 yrs younger, I'd go for the single assuming the engine was a well known make. One other factor is that the single would probably be faster. If I remember correctly, the Ad31's are 130hp so the small amount of extra power would be more than offset by the extra weight and extra drag of the 2nd drive
 
Surprisingly the 1994 boat is almost identical but has some nice 'personal' touches so there's little to gain on that score.
 
Corky said:
I'm looking at 2 boats currently, one is a 2002 model with a single diesel engine 250hp with bowthruster, the other is a twin engined (AD31s) 1994 model with no bow thruster. Both are same model, similarly priced ( yet to be haggled) and both nice boats. The question, I suppose is, knowing there are pros and cons of two vs one engine - has anyone gone from a 2 engine setup down to one and was it a problem?
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Well I was pleased to have two last Saturday when the port engine stopped whilst in the Solent. We went up to Swanick on one engine then found that if the port engine is out the bow thruster cannot be initiated. We used to have a single engine boat with bow thruster and had very few problems. A twin engine boat, on one engine with no bow thruster is challenging to moor with a bit of current and wind. I like the comfort feeling of having two engines in case one goes down but would not be concerned about going back to a single engine set up.
 
one or two ?

Looking at your location then twins would be nice.However it also depends on you boat useage.
If you are a out in all weather/seasons and always disappearing off to far flung over the horizon long distance destinations,then would always want a twin set up.
If on the the other hand you is a fine weather twicer a year on hot days only man happy to visit the bay just round the corner (again) then the single may appeal.
As for age,would pick the best maintained boat in the best overall condition and worry very little about if the interior is old fashioned solid actual tree wood materials as opposed to any highly transitory "o so last year" "instant scratch n chip " shiney cherry/ash/lime/oak finish.
 
[QUOTE it also depends on you boat useage.
If you intend some interesting boating and not just blasting from marina to marina then you have no choice: UK rivers and European waterways will be in your reach with a single shaft-driven engine, while longish keel and protected prop/rudder facilitate a dying berth, a huge financial saving.
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Twin for me every time, the only downside is to lumps of metal to service £££££ but well worth it if one of 'em stops!
 
The question, I suppose is, knowing there are pros and cons of two vs one engine - has anyone gone from a 2 engine setup down to one and was it a problem?
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All comes down to the depth of your wallet, your attitude to risk and finally how confident you are with your manoeuvring skills - different stokes for different folks as they say.
Personally I’m entirely happy with one good engine and a rudder.
 
I'd go for the single engine for cost reasons, annual maintenance cost alot cheaper, general cost of having something fail on two engines and the fuel cost savings with one. You can mitigate the risk of a single engine failure or prop fouling by subscribing to something like Seastart, having spares and making sure the single engine is well maintained. I do admit that I've had two failures on my boat in the last few years - bracket sheared off and snapped three drive belts, however I had spares and I was up running again within an hour. The other was a fishing rope, prop removed and rope cleared and running again - on both occansions Seastart assisted.
 
Thanks

Thanks to all for your thoughts. The boat is a 30ft planing hull and the usage would be regular (80hrs a year) and while not fair weather, I'm happy to sit in harbour till things blow over. Speed isn't the essence and having had single engines for the last 20 yrs I've just ensured the sngle is reliable. Plus I'm usually in Seastart range. I was just interested to hear some ideas of what anyone who went from 2 to 1 felt.

I'll probably go for the newer boat with the single engine.

Thanks again.
 
Corky said:
I'll probably go for the newer boat with the single engine.
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Seconded. Given the alternatives you mentioned, that would be my choice either.
But 250hp (or 260, for that matter) on a planing 30 footer is pretty much on the borderline of being underpowered imho.
 
The only disadvantage I can see of having 2 engines is one of money...

You have a spare engine if one breaks.

If you have twin fuel tanks as is often the case with twin engines then you have a degree of protection from fuel contamination.

A twin is infinitely more manoeuvreable.

The fact that the engines are not on the centreline of the boat makes the boat is more laterally stable.

However, more expensive to buy, run and maintain.

Two engines for me every time given the choice. However, the money aspect is a big one and so if it is a single engine or none at all then a single is not an unreasonable choice.
 
Paul

There are plenty of pros and cons for both sides of the debate, but one point that is often raised (not having a go at you personally), is the advantage of twin fuel tanks on a twin screw installation, as protection against contamination.

If the fuel taken onboard was dodgey, it would be put into each of the tanks so both engines would be effected.

If the bug develops due to a suitable growing environment from condensation (low fuel levels), both tanks are usually the same level, so should have a similar level of condensation.

A single screw boat can always have an auxilary fuel tank.

Just a thought.
 
AndieMac said:
If the bug develops due to a suitable growing environment from condensation (low fuel levels), both tanks are usually the same level, so should have a similar level of condensation.
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a common misconception, fuel bug does not require condensation to grow, or even a fuel water interface. There are many types of diesel bug, and many will grow in diesel alone.
 
Andiemac... I didn't mention anything about the bug!

You are right of course... if you fill both tanks at the same time & from the same supplier.

Unless I was going on a long trip, I would always only fill one side per visit ensuring I had a clean supply. Not possible on long passages I accept that. But most boating is done pottering near your home port when filling just one side on each visit to the pumps works well.

There are other types of contamination too... solid such as sand, liquid such as water... both of which can get in through the filler cap.
 
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