horses

[Metabarca]

Dear all,

I'm in the process of shopping for a new (old) boat and wanted the panel's advice on the following. I am viewing three examples of the same 32 foot sailing boat. All things being equal, should I prefer a 25hp Volvo to a 17hp Volvo or is the difference actually fairly minimal when all is said and done? More specifically, will I notice more vibration and noise with the 17hp to maintain a given speed than I would with the 25hp? Will the 17hp simply not have as much oomph?
Thanks for all comments received.

<hr width=100% size=1>Adriatic links here: <A target="_blank" HREF=http://www.comoy.com/saillinks.html>http://www.comoy.com/saillinks.html</A>

 

[capricorn]

Several factors to consider:

Displacement, 17hp probably plenty for a modern 32ft AWB but presumably your older boat is considerably heavier.

Sailing Area, Fron your profile it looks like you're med based. Extra power much less important when you don't have to punch into a head tide.

As I'm sure you know hull speed is a factor of waterline length. Take the low powered one for a motor and see how easy it is to reach hull speed. If you have to firewall it in a flat calm its probably not enough.

For an older boat, condition of the engine would be the deciding factor for me.

<hr width=100% size=1>

 

[snowleopard]

in the 'old days' the rule was 1hp per ton for an auxiliary, 3 for a motor sailer. but then sailing boats only used the engine for manoevering in a calm.

these days it's more like 3 hp/ton for an auxiliary and 6+ for a motor-sailer.

a big engine is a great thing to have when it's come on to blow and home is upwind, it means you can furl the sails, start the engine(s) and head straight for it. (s*d the purists, mine is 10 hp/ton!)

<hr width=100% size=1>

 

[Talbot]

I am sure that you would recognise that it is not a head tide that shows the difference between a big and a smaller engine (unless the big one can push you above hull speed) but pushing against a strong wind and waves. To the best of my knowledge, this still occurs in the med as well as thoroughout the "summer" in UK /forums/images/icons/smile.gif

<hr width=100% size=1>

 

[Roberto]

counting the number of times I thanked the extra hps of my engine, no doubt go bigger

ciao


<hr width=100% size=1>

 

[Metabarca]

Thanks for messages so far.
Length on waterline is: 7.45m, displacement about 5000 kg. What I want to know is, when the bora starts blowing and I'm the wrong side of the bumpy bits, would an extra 8hp (ie 25hp) actually be noticeable?
Perhaps I'm a little paranoid (I've had to do with 7 hp until now, and that has sometimes rather felt like being on the Pamplona bull run with two sprained ankles and a thundering noise behind...)

<hr width=100% size=1>Adriatic links here: <A target="_blank" HREF=http://www.comoy.com/saillinks.html>http://www.comoy.com/saillinks.html</A>

 

[Talbot]

<blockquote><font size=1>In reply to:</font><hr>

Length on waterline is: 7.45m, displacement about 5000 kg. What I want to know is, when the bora starts blowing and I'm the wrong side of the bumpy bits, would an extra 8hp (ie 25hp) actually be noticeable?


<hr></blockquote>

YES definitely.

<hr width=100% size=1>

 

[mirabriani]

P B O Circa 1998
"Tide is King"
However, if it were my choice I would go for the best engine.
A friends new engine cost more than the boat!
Briani

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by mirabriani on 22/09/2004 19:36 (server time).</FONT></P>

 

[Aja]

Agree!

Donald

<hr width=100% size=1>

 

[bedouin]

Noticeable - Yes, critical - No. I guess that (below hull speed) power required is a function of the square of the speed, so that extra 8hp would equate to about a 20% increase in speed.

There are down-sides to the bigger engine as well, such as greater fuel consumption and more drag from the correspondingly bigger prop.

<hr width=100% size=1>

 

[powerskipper]

Dame and I thought it was about gee gee horses, not the kind that eat oil and drink fuel /forums/images/icons/frown.gif

<hr width=100% size=1><A target="_blank" HREF=http://powerskipper.mysite.freeserve.com/>http://powerskipper.mysite.freeserve.com/</A>
Julie

 

[SPROUTZ]

I have had a 33 footer for 22 years wih a Volvo 24 HP engine and I was quite unhappy due to oil leaks nearly since new and low performances of the fridge with the compressor connected to the engine.
Engine reconditioninig made at you boatyard in Monfalcone was a waste of money.
When I replaced the engine with a new 28 HP Volvo, performances of the boat against the Bora and the Meltemi improved a lot and the Frigoboat frigdge was even able to freeze a can of beer.
Further discussions with owners of boats similar to my old Gladiateur ( 5 tons displacement) always indicated that a 18 HP engine was not enough for the boat in the Med.

<hr width=100% size=1>

 

[Talbot]

I assume from your criptic post that you disagree with me. I can only post from my own experience. My boat has a 27 hp diesel outboard. A similar boat has a 9.9hp saildrive outboard. Our speed on a relatively calm sea is almost identical. When the wind and waves are against, I slow down a tad, the other boat stops.

No argument as far as I am concerned unless (as I said in the first post) your engine is actually large enough to push you above hull speed.

<hr width=100% size=1>

 

[Talbot]

I assume from your criptic post that you disagree with me. I can only post from my own experience. My boat has a 27 hp diesel outboard. A similar boat has a 9.9hp saildrive outboard. Our speed on a relatively calm sea is almost identical. When the wind and waves are against, I slow down a tad, the other boat stops.

No argument as far as I am concerned unless (as I said in the first post) your engine is actually large enough to push you above hull speed.

<hr width=100% size=1>

 

[mirabriani]

I bow (twice) to your greater experience
Regards Briani

<hr width=100% size=1>

 

[Evadne]

1hp per ton? I've got a tad over 2hp per ton (6.5hp, 3.5 tons) and am seriously underpowered, especially at this time of year. Mind you I don't need such a big fuel tank.

<hr width=100% size=1>

 

[aitchw]

Don't you find, as I do, that a slightly bigger engine working less hard does not always use significantly more fuel than the smaller one working it's nuts off. Plus wear and tear is reduced and there is more chance of having enough extra punch in adverse conditions to get you home. Within reason, I would always prefer the bigger engine.

<hr width=100% size=1>