Tahiti in twenty days ?

My neighbour is off to Tahiti in the morning.

He seems a nice chap, and supported by a solid and experienced crew aboard a 65'ish sloop hopes to make 5000NM in 20 days.

It is always nice to over emphasize ability, be it the number of pushups in the morning, the size of that king salmon in Alaska, or the ability of one's yacht.

250NM a day - average - , is good going offshore downwind. I've crossed the pond thrice and heralded 250 as a celebration!
Looking at his yacht sitting opposite it seems unlikey to me that this target can be met - and at best imprudent to challenge the Pacific victualed for such a fast crossing!

So, my query is how sustainable is it for any boat to maintain a speed greater than 1.25 times the root of waterline length ?

I understand it is dependent on sails, trim, crew ability, wind, forecast, etc.. but in a perfect world would anyone expect a 65'ish sloop to make 5000 ocean miles in 20 days?

 

Is it downwind at this time of year? Far nicer to take the scenic route via some islands like ...... Just empty miles of ocean - Sorry guys - wrong side of the pond... anyway, what is the hurry?

 

I would say yes.

If he gets at least 15 days of really good winds.

Passage time, as I see it, is a game of averages.

Days of light, fluky, and variable winds must be made up with days of absolute stellar performance. The longer the passage, the less likely this is to happen.

Say he gets five days of absolutely crappy winds and only averages, say, 5kts.

Now he has 5kts * 24hrs* 5days or 600 nm for five days.

This gets subtracted from 5000 nm, leaving 4400 nm left to travel in just fifteen days. 4400 nm/15 days comes to 293 nm/day to finish the voyage on time.

293nm/24hrs = 12.2 kts he would have to average for the rest of the trip.

Assuming his LWL is 60 ft, that means he must sail at 12.2 kts/7.75 (sqrt of 60ft) or at a hull speed ratio of 1.57.

If he has a more modern light displacement sloop which can often sail well past the traditional hull speed ratio 1.34, he may well still have a chance.

It must be remembered, though, that it's not just light winds that can slow you down. Storm conditions can be just as effective, if they force you to slow down or even heave to.

It may well be possible and I wish him the best of luck on his passage, but it is not as easy as it looks.

Bob

 

OK so are we looking at 50 to 100 days - a good strong fishing line and many lures (fresh fish), now we need water & vegetables... ??? Oh and frozen "fresh/pure" lime juice to prevent scurvy he he he

Where is the port of departure? up near Washington State?

 

Is he on a racing yacht in the Tahiti race? if yes,then much more likely than a 65 ft cruiser,still not easy though,you say the boat was sitting across from you,how about a name.
Steve.

 

i aint got nuff fingers to keep up with ya's math hehe
wait a minute,i'll take my shoes off hehe

 

I did a study of recorded Best Days Runs ... a S/L ratio of 1.5 was about as good as it got starting in the 60's. Banking on a 250m/day average is a bit of a stretch ... could be done ...

 

No I'm with Randy on this, they won't to do it sailing.

Only racing boats with pro crews achieve over 10 knot averages sailing on long passages. It is very hard to do even with a hard bitten crew on the rail and a mean racing hull carrying everything the boat will stand when the wind blows. A cruiser has no chance unless they have a powerful motor, a hull that motors well, and they use it often.

 

No way in the world would a normal yacht do that sort of milage in 20 days, she would have to be a serious racing type hull with a crew of 20 to do it. 250 a day is good, very good, but a 65 is , very good.

 

Owen, since you started this thread, please be so kind as to tell us how long she took, and if/how many hours running the iron sails?

Thanks
Brian

 

I made Tahiti in 20 days from San Francisco in '95 on a Swan 36. As I recall we had decent breeze the entire passage, lots of reaching some running, 12 to 18kts ave. TWS the whole way except a realitive calm for about 24hrs as we passed thru the ITCZ. The passage could take a very long time if you pick the wrong place to cross the ITCZ -- Get good weather routing for that (Commanders).
Stay clear of the Tuomotus in the dark. Have fun

 

Lucky man - fast passage... Congrats on your good luck.