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Old 12-11-2012, 21:30   #16
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The wind matters a little bit. When it's blowing ten knots you won't be going 8.1.
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Old 12-11-2012, 22:01   #17
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Re: Passage Speed

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Originally Posted by Weyalan View Post
Please specify the units. I assume
SA = sail area, but it is square metres, square feet, acres, etc? Likewise
D = displacement, but is that kilograms, pounds or tons (imperial long, imperial short or metric)
LWL = waterline length, but metres, feet, rods, perches or furlongs
You really went out of your way to find perches for your post didn't you?

LWL is in feet.

The ratio SA/D = SA / [(D / 64)^0.6666]

D = Displacement in LB

SA = Triangular area of the main excluding roach and the area of the foretriange (ie. 100% jib, no overlap)

You didn't ask but I'll state the obvious and note that mileage refers to minutes of arc as measured from the center of the earth (AKA Nautical Miles).
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Old 12-11-2012, 22:29   #18
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Re: Passage Speed

I wasn't meant to be cheeky at all. honest
But it isn't immediately clear whether to use American units (feet and pounds) or rest of the world units (metres, kilograms) and, despite what another poster says, these will give different results. Sorry for my impertenence
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Old 12-11-2012, 23:16   #19
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Re: Passage Speed

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The wind matters a little bit. When it's blowing ten knots you won't be going 8.1.

No?

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Old 13-11-2012, 00:25   #20
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Re: Passage Speed

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Am I missing something or did you just show me 11 knots apparent in a quartering wind?
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Old 13-11-2012, 00:37   #21
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Re: Passage Speed

Type of boat - cat, tri, mono can obviously as pointed out by others have different short term speed differences. But if you are interested in how much time it takes to get a sailboat from one harbor to another while cruising, then I would say the Mono is the best.

Although the cat & tri are faster in optimum wind and sea conditions, the mono can keep on slogging (like the energizer bunny) when the other boats need to reduce speed or stay in harbor. Pointing ability also makes a significant difference. I once beat a cat crossing the Anegada Passage because I could point higher while he with his greater speed had to fall off more to hold the wind.

So like the turtle and the hare, on passages the boat that can stay out there clicking off the nautical miles will beat the boats that cannot.
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Old 13-11-2012, 01:24   #22
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Re: Passage Speed

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Ah right, thats essentially what I'm trying to work out. So in cruising trim, would it be fair to say that say a Dragonfly 920 would cover similar ground to a modern, plaining hull 32 foot mono (very roughly)?
Not even close. The DF will be very much faster than a 32 ft mono - The Df is quicker than me, and if a 32 ft production cruising mono beats me, I will buy it.

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....how much time it takes to get a sailboat from one harbor to another while cruising, then I would say the Mono is the best.

Although the cat & tri are faster in optimum wind and sea conditions, the mono can keep on slogging (like the energizer bunny) when the other boats need to reduce speed or stay in harbor. Pointing ability also makes a significant difference. I once beat a cat crossing the Anegada Passage because I could point higher while he with his greater speed had to fall off more to hold the wind.

So like the turtle and the hare, on passages the boat that can stay out there clicking off the nautical miles will beat the boats that cannot.
And yet in the real world of cruising sailors, eg the recent Louisiades rally and last years similar events the cats were anchored well before the monos. The quickest was a chincogan 52 (Grainger design) Seawind 1250 and 1160 were next. In the Vanuatu Rally I think 44 Cruising Cat should be able to give us more info but I understand it was similar.
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Old 13-11-2012, 03:52   #23
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Quote:
Originally Posted by rebel heart

Am I missing something or did you just show me 11 knots apparent in a quartering wind?
Looked like 8-9 kts boat speed in 10-11 kts true wind on a broad reach, not the fastest point of sail. We figure the speed on our boat at 70-80% of true wind on a good point of sail. That would be 7-8 kts of boat speed in a 10 kt wind. Of course that wouldn't be the figures for going close hauled or dead down wind.
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Old 13-11-2012, 05:28   #24
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Re: Passage Speed

I'm glad I started this now, looks like an interesting debate!

So it seems from what I can gather, that in short races a multi (probably a tri is better), however for longer duration cruises (and maybe races?) it becomes a much greyer area.

I'm guessing that the hypotheticals go out of the window for this and its down to those with real world experience to share their knowledge?

Anyway, thank you for all your help so far, I am learning a lot!
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Old 13-11-2012, 06:02   #25
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Re: Passage Speed

Well, I don't know about the Sun Fast 3200...............

However, I have a Sun Fast 40.3. Theoretical hull speed just under 9 knots. I have reached this a number of times. This summer, I ran downwind in force 8-9 and racked up at 10,5 to 11 knots (we were planing). But we couldn't hold that speed. We did the 36 NM from Falsterbokanalen to Ystad in just under 4 hours (so just over 9 knots average). The next day we did the 47 NM from Ystad to Allinge (on Bornholm) in under 6 hours (average just under 9 knots). The wind day two was force 7.

So yes, she's fast. Could we do 200NM days? I doubt it. I doubt I would want to since we are only two aboard.

Would I want to try 22 knots (as per the link on the 3200)? HELL NO! I'm not an idiot. The slightest helm error and you've screwed an entire kennel of pooches.

By the way, the 40.3 is a cruisers dream - lot and lots of comfort inside. Nice finishing touches.

Not many of them around - but a great boat
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Old 13-11-2012, 06:09   #26
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Re: Passage Speed

Apparently there is a Sunfast 3600 being released at the Paris boatshow in December, should be very exciting!

I've not come across the 40.3 before, will check it out!
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Old 13-11-2012, 06:51   #27
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Re: Passage Speed

Quote:
Originally Posted by Factor View Post
. . . And yet in the real world of cruising sailors, eg the recent Louisiades rally and last years similar events the cats were anchored well before the monos. The quickest was a chincogan 52 (Grainger design) Seawind 1250 and 1160 were next. In the Vanuatu Rally I think 44 Cruising Cat should be able to give us more info but I understand it was similar.
Make that "in the real world of rich cruising sailors . . . " I looked up those catamarans and wow, they are really great 40ft to 52 ft boats. And if I had the nearly half million dollars to 3/4 million dollars it takes to buy one, I would. And for that money speed would be expected along with all the other fabulous features of those boats.

But down here in the world of budget cruisers, where the OP most probably is looking for a well used rugged, reasonably reliable boat (just a guess, he may be filthy rich) at an economical price, I would suggest the best "bang for the buck" would be in mono-hulls.

As others have posted, when "loaded for cruising" the speed differential between cat and mono in terms of getting from one fabulous harbor/island to the next fabulous island/harbor is not significant. But, IMHO, the ability to slog along in reasonable comfort in rough wind/wave conditions is the best feature of monohulls.

However, if money was not a limiting factor, then catamarans are definitely the go, not so much for their speed, but instead for their accommodations and ability to ride flatter when at anchor in rolly harbors. For the Caribbean I think catamarans are definitely the overall winners considering that you will be spending 90% of your time anchored in one place or another.
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Old 13-11-2012, 07:01   #28
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Re: Passage Speed

Haha, I'd love something shiney and new :-)

But your assumption of a 'well used rugged, reasonably reliable boat' is spot on in reality.

My plan is to buy something to mess around on initially, say £5k, just to learn the basics, or possibly just charter more (cost will be about the same over the course of 1 year, for chartering a few times vs buying for 5k +fees, maintenance and then selling on fairly quickly), then get something a bit more suited to my needs in due course.

I think also one key point that you rightly point out is location, I live in South East England, hence the South Coast, Channel Islands and Northern Coast of France / Eastern Coast of Europe would be my likely cruising grounds.
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Old 13-11-2012, 07:03   #29
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Re: Passage Speed

Here's a link to a Sun Fast 40.3 that is for sale
Sailing yacht JEANNEAU SUN FAST 40.3 [year: 2005] used - Sailing yacht for sale - EYB

95K euros is a good price.
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Old 13-11-2012, 07:09   #30
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Re: Passage Speed

"Average" is the key word - and it's VMG, not straight line speed. Multihulls go like gangbusters on their ideal points of sail and when they are tended by aggressive crews. No one doubts that.

But in a variety of seas and on a variety of points of sail (and with mostly mom-and-pop crews), things start to even out a bit.

I would suggest that something like the Carib 1500 is a good test of reality. On average the longer waterline monos tend to do as well or better than the multis. World Cruising Club Carib1500 Fleet Viewer
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