What makes a Yacht go faster

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TonyS

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What do forumites think affects boat speed the most.
Clean bottom 75% - 1.5 kts
Folding Prop 15 % - 0.3 kts
Performance sails 10% - 0.2 kts
or is it boat dependent?
 
From my limited experience over the past year I'd say a clean bottom and properly trimed sails. Sexy sails would be nice but they'd still be useless if they were badly trimmed.
 
Either sailing to the wind or trimming the sails regularly. Maximising the sail area for the conditions. Use of spinnaker or cruising chute. The mainsail is not just hoisted and sheeted centrally either, regardless of the point of sailing. Yes Mr Moody/Bavaria Owner ;-)
Trimming the sails to avoid extreme weather helm - cant tell so easily with a wheel, just when it hits the end stop and then the boat luffs into No Mans Land Fort (Bavaria seen on Round the Island 2004)
And a nice big engine with no weed on the prop.
 
Hull/Boat design.

Having crewed on an 8 metre J80 travelling at 17 knots, (and regularly above 10 knots) which is way above it's theoretical hull speed

The hull hummmed!
And sometimes so did we!!!
 
Concentration.

During the long distance races it's amazing how many good boats slow down at night, when concentration lapses. And 'set and forget' mentality sets in.

If every last tenth of a knot is what you want, that's the difference between a good crew and a great crew.
 
Agree with most of what's been said, but would stress the clean hull and constant concentration on sail trim. The trimming is what tends to suffer first on cruising (i.e. not racing) boats, and there's nothing wrong with that - as long as you accept that speed/pointing will suffer. As Robb says, most cruisers 'slow down' at night because of this.

Design is outside anyone's ability to change if you have a production boat - you sail what you've got! Forethought's summary just about covers it all, especially re the weatherhelm. Trimming this out is probably the most neglected element on the cruisers I've sailed, with some skippers creating huge drag with <15 deg of helm.

Tickles me, 'cos these are often the very chaps who've insisted they must have an expensive folding prop "to get an extra half a knot!!

Cheers Jerry
 
Ahem, as one with a folding prop, I'd say it depends a bit where you are on the experience curve.

Sure, sail trim, concentration, etc are important but once you have these sorted you can't overcome the laws of physics with those. Then things like good sails, clean bottoms and folding props all contribute to aiding boat speed especially in lighter airs. In our case, we swapped a 130% 10oz genoa for 150% 9oz and that gave us a good knot in winds <=F3, swapping to a folding prop added abt another 1/2 knot in winds <=F4. As a result we now plan our passages at 6 knots rather than 5.

And, of course as tcm says don't forget the donkey, we've also replaced the old wheezing Thorneycroft 30 hp crusing speed abt 5 knots with a diesel sipping Beta 37.5 hp crusing speed 6 knots.
 
Is it true that humming boats have aphrodisiac qualities?? heard this is so with humming centre boards on peformance dinghies but wondering if this applies to yachts?? or should I just hum regardless??
 
All are true, but why doesn't anybody mention weight?. I can get a good 500 kgs, off the boat for club regattas (low tank usage, dinghy, dinghy engine, spare parts, tools, etc.). Guess this doesn't work with cruising on one's mind since most of us load up, but it IS an important speed factor.
 
Ah 'tis the eternal quest! all those little things that can be done
will add up to a fair bit but if you can't trim yer sails..... The gap between the genoa and mainsail is crucial. Stand on leward quarter and look up at trailing edge of both sails. They should run parralell with a nice bit of twist up top. Also look at curve of foot of both. Should also be p//.. If you sometimes wonder why when everthing is set and seems ok she still does not seem to be realy going 'mind the gap'/ slot, tis where the apparent wind exits the surface of the sails after accelerating through the slot. Dont squeeze it too much..
 
Hi Chris,

Yes, entirely agree with you! My point was that one or two of my friends still sail with huge weatherhelm (IMHO) that could be trimmed out or substantially reduced, yet have invested in expensive folding props to help their speed!

Do BOTH by all means, just seems odd to to me not to do the obvious first/as well!

Cheers Jerry
 
Money, of course

"Now, Fife, I haven't got money to burn, but if it makes her any faster, just shovel on the notes!"

Sir Thomas Lipton to William Fife III, ordering his third America's Cup challenger, Shamrock III, about a century ago.

Seriously, I agree with your analysis - at least, its right for my old gaff cutter!
 
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