Beneteau 27.7 - Engine Horse Power

steveej

steveej

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Hi all,

I am looking for my next boat and am keen on the Beneteau 27.7.

There seems to be two engine options 9hp and 18hp. Obviously 18 is better but I trying to determine whether it is worth looking at the 9hp version as I am concerned it is too underpowered for my needs.

Displacement is 2,795kg for a Hull Length of 8.3M so it is a light displacement boat.

I am trying to gauge what sort of speed the 9HP engine could push this along at in flat water.

The first season will be in the Bristol Channel in Cardiff so there are some strong tides, especially when trying to get back to Cardiff after going west for the weekend.

Last boat I had was a Hurley 22 at 1,814kg displacement and 6HP and that was about the minimum that was acceptable to cope with Bristol channel tides. In terms of ratios the increase in HP from 6 to 9 is about the same in terms of displacement i.e. a 50% increase.

Hurley 22 LWL is 5.18 so going up to 8.3M is more than a 50% increase.

Looking at these figure it seems that 9HP is just about acceptable but is my thinking correct?

Of course sailing back should be no issue but there isn't always wind.
 
A good friend had one of these with the Yanmar 1 gm which IIRC is the standard engine on these. It went fine and I'm pretty sure you could get above 6 knts in calm water and in any wind they sail faster than they can motor! You should be fine as there are loads out there rock hopping in tidal Brittany waters!
 
steveej said:
The first season will be in the Bristol Channel in Cardiff so there are some strong tides, especially when trying to get back to Cardiff after going west for the weekend.
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You're obviously concerned about this, so why not narrow your search to boats with the bigger engine? Apart from anything else, you won't be running a small engine flat-out to get anywhere.
 
That is the problem if you limit your engine supply to Yanmar when at the time there was no engine between the 1GM and 2GM (since rectified with the YM range).

The 1GM is adequate and it does not mind running almost flat out for hours on end, but you have to accept that it is an auxiliary to a sharp sailing boat rather than a get you home on time means of power.
 
If tides and motoring into chop is a concern the your concerns are correct. It would be fine on flat water with no tide but add in some waves and wind on the nose and you'd always be looking for more power.
 
Tranona said:
That is the problem if you limit your engine supply to Yanmar when at the time there was no engine between the 1GM and 2GM (since rectified with the YM range).

The 1GM is adequate and it does not mind running almost flat out for hours on end, but you have to accept that it is an auxiliary to a sharp sailing boat rather than a get you home on time means of power.
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This is a concern because I do work full time and the plan for this is for it to be a fast weekend cruising boat.

There is one in NWales on for 25 with 9HP. One in Ireland for 23 with 18HP but doesnt look as good condition from photos. One in Brittany for 22 photos look like chaos down below with cushions everywhere but might be ok.

I was going to buy a Bavaria but since we are moving house my budget has been slashed.
 
I would think carefully about that extra power with the 2G20, I find it useful. I have this engine on a perhaps slightly larger 28-29 foot yacht about 3200kgs loaded up sailing weight. Spec’ed at 2400kgs empty witout engine. On a three blade feathering prop. A perfect match in my view. Averaging 1.34 litres per hr. It has enough grip on the water in choppy harbour entrances, it can go flat out (rated for a limit of 1 hour flat out) to get to start lines quickly, can go flat out to get back in the harbour against a strong foul tide, has enough grip on the water to manoeuvre ok, very smooth at normal high operating rpm and starts sooo easily. Also I reckon the 2GM20 is slightly less prone to the blocked exhaust port problem. But if I was a a race purist then I might be interested in saving weight knowing that if too windy and rough then my race would have been cancelled anyway.
 
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Channel Sailor said:
I would think carefully about that extra power with the 2G20, I find it useful. I have this engine on a perhaps slightly larger 28-29 foot yacht about 3200kgs loaded up sailing weight. Spec’ed at 2400kgs empty witout engine. On a three blade feathering prop. A perfect match in my view. Averaging 1.34 litres per hr. It has enough grip on the water in choppy harbour entrances, it can go flat out (rated for a limit of 1 hour flat out) to get to start lines quickly, can go flat out to get back in the harbour against a strong foul tide, has enough grip on the water to manoeuvre ok, very smooth at normal high operating rpm and starts sooo easily. Also I reckon the 2GM20 is slightly less prone to the blocked exhaust port problem. But if I was a a race purist then I might be interested in saving weight knowing that if too windy and rough then my race would have been cancelled anyway.
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What boat is that?

This one is 29 LOA and just over 27 LWL
 
The 27.7 has a very easily driven hull and is relatively light weight for its size.

We have a similar slightly larger and heavier boat with a 10 HP engine.

The only time that we really struggle is if having to motor into a short wind against tide chop usually to meet a tidal gate around here. It can be mitigated by getting into calmer water out of tide or motor sailing!
I think you would be right to be concerned. However I would not be deterred from buying a boat that is easily driven by motor or sail for the few times a small motor could be a disadvantage.

The 27.7 is a lovely performer.
 
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steveej said:
What boat is that?

This one is 29 LOA and just over 27 LWL
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Jeanneau 29 Sport, 8.75m LOA 7.05m water line length. I also notice that if 30kts-35kts of wind appears unexpectedly in the sheltered or harbours in flat ish water, then I still seem to have a reasonable degree of control and speed. This is probably helped a lot by a three bladed prop'. But of course I have not tried the smaller engine in the same boat, so the 9hp one could be just fine too.
 
Whilst it is always nice to have a little power left in reserve for 'a bad day' remember that, at 2 feet smaller than yours, my Jeanneau Eolia 25 never needed full throttle to get to hull speed using it's 9hp Yanmar 1GM10.

Mind you, the 33' Aphrodite 101 also had the same 9hp engine.

Good if you like economy, simplicity and reliability. Bad news if you like smoothness and hot water.
 
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