How many engines?

[britemp]

I am trying to decide between 1 or 2 engines.

If I order a Targa 27.1 with a Volvo D6 it will do around 38 knots. If I order the slightly larger Targa 30 with 2 x D6 it looks like it will do about 45 knots. The 27.1 can only have 1 engine AFAIK.

That's not a lot of knots for an awful lot of notes (pound!).

I really like the idea of 2 engines for safety etc but in the above case it doesn't really seem much benefit (plus 2x fuel consumption) as the 27.1 is big enough for my needs.

Being new to this and with my Norfolk Broads experience being limited to a 44 footer with a 30hp lister-petter, am I in my noobishness, missing something obvious or is 1 engine OK?


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[tristan]

There is always more security and inherent safety in 2 engines and the larger boat will have more volume and a better cruising aspect (it will be a more comforfable ride!)
Having said that, the fuel costs will be higher and the maintenence will double so it is a trade-off either way.
My personal choice at the moment would be to get the 30 with twin KAD300's if it is still an option - the D6's are not yet experienced enough to justify that one year warranty (and the power to weight ratio is much higher)

Any more questions plese ask.

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[Col]

Two engines don't neccesarily mean twice the fuel consumption.
If you're whizzing around at WOT all the time, then yes, you probably will double it.

Most people adopt a comfortable cruising speed, this means 2 engines sharing the work so neither is running as hard as one would be on its own. If you get it right, 2 won't use a huge amount more than just 1.

Factor in the better manouverability, and safety in having 2 engines makes my choice a twin every time.

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[Col]

Two engines don't neccesarily mean twice the fuel consumption.
If you're whizzing around at WOT all the time, then yes, you probably will double it.

Most people adopt a comfortable cruising speed, this means 2 engines sharing the work so neither is running as hard as one would be on its own. If you get it right, 2 won't use a huge amount more than just 1.

Factor in the better manouverability, and safety in having 2 engines; makes my choice a twin every time.

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[mainshiptom]

I would always go for two !

It is not only the engine but also two leges/rudders and two props in case one fouls up ?

We have very reliable engines but one did fail last year due to a silly fault !

We got into Harbour on one engine no problem, what would we have done with one ? and what about our pride ?

Go for two ! Once at sea you will never regrat it , you will save on the extra prop on the bow !

Tom

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[hlb]

Planing boats are fairly unhandlable in close quarters with one engine. With two there a doddle. Plus what others have said.

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[tcm]

Re: How fast is fast?

I imagine that this is your first boat?

When we bought our firstboat, I was worried sick about the dog-slow speed. 34 knots was the maximum listed, and then someone said that it might not even be able to do that if it was loaded with fuel!

However, i can tell you that altho 30 knots is rubbish for a car, in a boat on anything but a smooth lake it is mentally fast. The boat gobbles fuel at an horrendous rate, and everyone is holding on for dear life. Any loose towels and other clothing risks getting whipped overboard. See if you or a passenger can hold there head out of the window in a car at 30mph without tears streaming and you will se what i mean. Then try the same thing over a ploughed field to get an idea of a boat over some waves.

These days we bimble along at 20 knots, nice comfy trip, no stress, no problem. You do not need a boat that does 40 knots and most have a boat that does nowhere near this speed.

You can ignore this advice - in the same way as I initially ignored anyone who would say erm look, 30 knots is pretty damn quick. Later , they came on the boat at 27 knots, hung on tight and said yeah, I was right, huh? And they were. I asked the manufactuer about the massive fuel consumption: they said drop to 22 knots and it will be half. SWMBO very pleased we did so, and anyway these days the towels fly off the front if we go above 18 knots.

Space-wise, i would imagine that the larger boat has loads more space. Again, this isn't like cars, all of which need to be nearly the same size else they won't fit on the road. Note that (unless the 30 footer has a huge bathing platform) then the space increases in proportion to the cube of the length. 27 cubed is 19683 , 30 cubed is 2700, in other words possibly 30% more volume. Ish.



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[Solitaire]

Oooh Hadyn, are you saying then that those of us who only have single engine (planing) boats and can handle them well in close quarters are better boat handlers than those with twin engines? /forums/images/icons/wink.gif.

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[Wiggo]

Re: No, no, no

The really good boat handlers do it all with the bowthruster.

<puts on tin hat, hides under desk>

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[Solitaire]

Re: No, no, no

/forums/images/icons/laugh.gif Another twin engine driver who has a "get out of jail" card then!!! /forums/images/icons/wink.gif

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[muchy_]

I have also heard that with twins if you catch a rope on both props the damage can be quite considerable if the the props are pulling against each other, bent shafts and the like.
Dont forget that twice the mechanicals means double the chance of something breaking anyway.
There is of course the old argument that if you only have one engine then it will be pretty well looked after but with two you can always take that chance with it because you have another one so they dont get as well pampered.
Just look around at all the fishing boats and tugs and things.......one engine (mostly).
Why not go for the one engine option and just get an outboard as an auxillary for emergencies? You have your radio as well, call for assistance if need be.

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[ipw]

The rib that crossed the atlantic had only one diesel cat engine .I was talking to the designer at sbs and said you are better having one engine, with plenty of space all round for better maintenance and emergency repairs than two cramped engines .

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[oldgit]

Re:Two please.?

If one is better than two.why did --------- (choose the deity of choice)give you two arms legs eyes ears and b..ls THEN./forums/images/icons/laugh.gif

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[Col]

At the end of the day, why don't you sea trial both a twin & single engine boat, and see which one you prefer.

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[britemp]

Thanks for that - I didn't realise the power-to-weight ratio would vary so much between the KAD300 and the D6 and it's £4k cheaper.

I guess my real problem is that to go from a 27.1 with 1 engine (£75k) to a 30 with 2 engines (£124k) is a huge amount of money for very little perceived benefit and because of the unusual design of the targa, very little extra space.

Having said that I really would prefer 2 engines but I'm not willing to spend an extra £50k for the privelidge!

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[britemp]

Hi Col

I agree with you and don't intend whizzing around flat out all the time but to go from a 27.1 with 1 engine to a 30 with 2 is a jump from £75k to £124k for 6 knots and a bit more elbow room I don't need.

Think I'd still prefer 2 but the £49k difference will buy me the TVR Tuscan S I want!


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[britemp]

Re: How fast is fast?

Certainly not going to ignore what you say - it pretty much reflects what I thought. I'm not bothered about top speed too much, but everyone tells me to always order a boat with the biggest engine option and it is one way of measuring what you get for the money.

The problem with the Targa is that it has a lot of deck space and going from a 27 to a 30 doesn't add much interior space but that doesn't matter to me much. The big problem is a 27.1 with 1 engine is £75k and a 30 with 2 is £124k - hell of a jump for not much.


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[britemp]

Will do.

Thanks to everyone for your advice - will consider it all carefully.


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[DavidJ]

"Dont forget that twice the mechanicals means double the chance of something breaking anyway."

Not so, say the chances of an engine breaking down in any one day are 1% (.01) then the chances of both breaking down in the same day are .01x.01=.0001 ie 0.01%, that's 100 times safer with two engines. That's one total breakdown every 10,000 days (ie 27 years)

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[foxgoose]

When I bought my 27 in 2001, I could have had twin 4cyl jobs or a single KAD 43.

The twin engines lose two of the 4 rather vestigial berths and Wessex advised against them saying they would be rougher, noisier and a bit heavy for the hull.

However, I think the new D4's would be smoother and maybe lighter - won't Botnia give you a price for these?

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