New Imoca's

5 years ago
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tarquin1
tarquin1
954 posts
954 posts
13 Jun 2020 7:44pm



These things are insane. How physically and mentally demanding is the Vendee going to be on one of these.
tarquin1
tarquin1
954 posts
954 posts
13 Jun 2020 8:05pm
Tried to attatch a vid but dosnt want to do it. Google Imoca Charal if you are interested.
Azure305
Azure305
NSW
402 posts
NSW, 402 posts
13 Jun 2020 10:16pm
tarquin1
tarquin1
954 posts
954 posts
13 Jun 2020 8:31pm
tarquin1
tarquin1
954 posts
954 posts
13 Jun 2020 8:36pm
Thanks AzureF305. That's an old one. They have just relaunched her with new foils and other mods.
SandS
SandS
VIC
5904 posts
VIC, 5904 posts
14 Jun 2020 10:00am
looks like the rudder and associated bits will take big hits !
2bish
2bish
TAS
825 posts
TAS, 825 posts
15 Jun 2020 8:36pm
I know, I can't imagine being switched on for such long stretches of time on such twitchy powerful beasts. I know they mostly sail them on autopilot once they're set, but still, it must be absolutely exhausting. And there's Alex Thomsons little dingle with Guadaloupe near the end of the Route du Rhum, to press the point. He was knackered and asleep. I'm really looking forward to the Vendee start!

A lot of the older foiling hulls have had updated foils added too, it's going to be a fast race.
Ramona
Ramona
NSW
7756 posts
NSW, 7756 posts
16 Jun 2020 8:39am
I believe the noise inside is what causes the most stress and exhaustion.
Strachan
Strachan
ACT
47 posts
ACT, 47 posts
16 Jun 2020 12:41pm
Yep, the noise must be incredible. One of the features in the last race was an interview with the race doctor. He said that it's a fairly constant 120 dB inside the hull as it's carbon fibre. Most skippers "sleep" with noise cancelling headphones on.
Strachan
Strachan
ACT
47 posts
ACT, 47 posts
16 Jun 2020 12:44pm
SandS said..
looks like the rudder and associated bits will take big hits !


I think I read that some boats are carrying spare foils this time. No idea how you'd change one in big seas. Last time Thomson broke one off (shipping container I think) and was fast on one tack and slow on the other without the foil. Amazing boats.
2bish
2bish
TAS
825 posts
TAS, 825 posts
16 Jun 2020 4:33pm
120dB.... man! that's a chain saw at full tilt less than one meter away, I'd be wearing my noise cancelling headphones the whole time.
Strachan
Strachan
ACT
47 posts
ACT, 47 posts
17 Jun 2020 5:22pm
2bish said..
120dB.... man! that's a chain saw at full tilt less than one meter away, I'd be wearing my noise cancelling headphones the whole time.


I slightly exaggerated. It varies between 90 and 120 dB: www.vendeeglobe.org/en/news/16517/ear-flaps

Still very unpleasant.
Andrew68
Andrew68
VIC
433 posts
VIC, 433 posts
24 Jun 2020 6:54am
Andrew68
Andrew68
VIC
433 posts
VIC, 433 posts
24 Jun 2020 6:54am
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shaggybaxter
shaggybaxter
QLD
2677 posts
QLD, 2677 posts
24 Jun 2020 8:22am
I often wonder if the Volvo boys look at the Imocas and grind their teeth for the Imoca's traits on protection from the elements. I get that you can't do this on a fully crewed boat, but man, I know which one I'd rather do the Southern Ocean in.




shaggybaxter
shaggybaxter
QLD
2677 posts
QLD, 2677 posts
24 Jun 2020 8:27am
And if you ever needed justification for a three point tether with a short strop....
That toe rail looks awfully important all of a sudden!




Strachan
Strachan
ACT
47 posts
ACT, 47 posts
24 Jun 2020 2:35pm
shaggybaxter said..
And if you ever needed justification for a three point tether with a short strop....
That toe rail looks awfully important all of a sudden!





Absolutely. Interesting how the foredeck is as clean as possible to allow water to run off, lightening the bow. Also not a deck-sweeping foot on the jib as there must be a sweet spot where not catching water is more important than sail area.
tarquin1
tarquin1
954 posts
954 posts
24 Jun 2020 1:06pm
shaggybaxter said..
I often wonder if the Volvo boys look at the Imocas and grind their teeth for the Imoca's traits on protection from the elements. I get that you can't do this on a fully crewed boat, but man, I know which one I'd rather do the Southern Ocean in.





There was an interview with David Witt I saw. They asked him Volvo or Imoca. He said Imoca. Going around the world on a Volvo boat is like someone spraying you with a fire hose any time you go on deck.
The Corum boat is launched now and there are some great articles about it. It's very different again. Scow bow. The foils are quite high on the top sides too.
wongaga
wongaga
VIC
661 posts
VIC, 661 posts
24 Jun 2020 5:30pm
Ramona said..
I believe the noise inside is what causes the most stress and exhaustion.


On a delivery trip of a carbon-fibre hull SH boat, for about a day we were running regularly topping 20kn (boat speed) and coming off 4-5 m breaking waves. Helming was exhausting but fun, but being off-watch was an appalling experience due to the incessant loud crash-bang noise, and the incredible jolting jarring and vibration. I can't imagine how those crews endure weeks of that.

I love my nice semi-full keel 55% ballast ratio, 14 SA/D old man boat!

Cheers, Graeme
tarquin1
tarquin1
954 posts
JakeNN
JakeNN
372 posts
372 posts
12 Jul 2020 6:29pm
wongaga said..
I love my nice semi-full keel 55% ballast ratio, 14 SA/D old man boat!
Cheers, Graeme


Just keen to learn here ... What is a semi-full keep 55% ballast ratio, 24 SA/D?

Does it get planing? Wouldn't it be nice to get planing, switch on the auto-pilot and enjoy the ride with a beer?
EC31
EC31
NSW
490 posts
NSW, 490 posts
12 Jul 2020 8:57pm


JakeNN said..



Does it get planing? Wouldn't it be nice to get planing, switch on the auto-pilot and enjoy the ride with a beer?


Probably a better question for ShaggyB!
wongaga
wongaga
VIC
661 posts
VIC, 661 posts
13 Jul 2020 10:20am
JakeNN said..


wongaga said..
I love my nice semi-full keel 55% ballast ratio, 14 SA/D old man boat!
Cheers, Graeme




Just keen to learn here ... What is a semi-full keep 55% ballast ratio, 24 SA/D?

Does it get planing? Wouldn't it be nice to get planing, switch on the auto-pilot and enjoy the ride with a beer?



Think of a 1970's 4-cylinder Volvo station wagon as compared to a F1 racer.
shaggybaxter
shaggybaxter
QLD
2677 posts
QLD, 2677 posts
14 Jul 2020 6:35am
JakeNN said..








wongaga said..
I love my nice semi-full keel 55% ballast ratio, 14 SA/D old man boat!
Cheers, Graeme










Just keen to learn here ... What is a semi-full keep 55% ballast ratio, 24 SA/D?

Does it get planing? Wouldn't it be nice to get planing, switch on the auto-pilot and enjoy the ride with a beer?









Hi Jake,
The ballast ratio is a percentage of the ballast compared to the dry weight. The higher the number, the more ballast is carried compared to the overall weight, which means more resistance to heel. Graeme's 55% compared to my 36% means as the weather gets a bit fresh Graeme is enjoying a nice cup of tea with full sails up as I am scrambling to downsize sail area to keep the boat on her feet.
The SA/D is a comparison of your total sail area to your displacement. Upwind I run a SA/D of 34'ish, downwind it jumps to about 65. Graeme's SA/D of 14 means as the weather gets fresh he is now enjoying a nice nap after his cup of tea, still with full sails up, as I am hanging on grimly as the boat charges off like it's been possessed . We start planing at about 15kn TWS and as the wind comes behind about 80 deg TWA.

To answer your question, yes its the best feeling in the world to sit back when the boat is trimmed, on the plane and it' s effortlessly soaking up miles. For Fusion, the lower ballast ratio is offset by a wider beam which lends a lot of hull form resistance to heeling, so gusts tend to be soaked up by the hull shape rather than put you over on your ear. That sort of thing isn't reflected in your SA/D or Ballast ratio, which is why there is a bazillion other calcs naval architects use to typify a boats manners.
So while a higher SA/D is enormously rewarding, you can't be lazy. Speed is fun, but if the comfort level goes way down to achieve this it gets a bit naff pretty quickly.
To apply this to the real world... Graeme and I are headed for same harbour and its been a bit fresh. Graeme may get their a tad later but he'll be dry, comfy, sporting a big smile and a hairstyle like he stepped out of Vogue magazine. I might get there a bit quicker, but I'll be soaked, tired, counting bruises, sporting a HUGE smile and a hairstyle like I stepped out of Just Mechanics.
Cheers!
SB
wongaga
wongaga
VIC
661 posts
VIC, 661 posts
14 Jul 2020 11:31am
Good grief Shaggy, you'll give people the wrong idea about Compass owners!
Datawiz
Datawiz
VIC
605 posts
VIC, 605 posts
14 Jul 2020 7:12pm
shaggybaxter said..

JakeNN said..









wongaga said..
I love my nice semi-full keel 55% ballast ratio, 14 SA/D old man boat!
Cheers, Graeme











Just keen to learn here ... What is a semi-full keep 55% ballast ratio, 24 SA/D?

Does it get planing? Wouldn't it be nice to get planing, switch on the auto-pilot and enjoy the ride with a beer?










Hi Jake,
The ballast ratio is a percentage of the ballast compared to the dry weight. The higher the number, the more ballast is carried compared to the overall weight, which means more resistance to heel. Graeme's 55% compared to my 36% means as the weather gets a bit fresh Graeme is enjoying a nice cup of tea with full sails up as I am scrambling to downsize sail area to keep the boat on her feet.
The SA/D is a comparison of your total sail area to your displacement. Upwind I run a SA/D of 34'ish, downwind it jumps to about 65. Graeme's SA/D of 14 means as the weather gets fresh he is now enjoying a nice nap after his cup of tea, still with full sails up, as I am hanging on grimly as the boat charges off like it's been possessed . We start planing at about 15kn TWS and as the wind comes behind about 80 deg TWA.

To answer your question, yes its the best feeling in the world to sit back when the boat is trimmed, on the plane and it' s effortlessly soaking up miles. For Fusion, the lower ballast ratio is offset by a wider beam which lends a lot of hull form resistance to heeling, so gusts tend to be soaked up by the hull shape rather than put you over on your ear. That sort of thing isn't reflected in your SA/D or Ballast ratio, which is why there is a bazillion other calcs naval architects use to typify a boats manners.
So while a higher SA/D is enormously rewarding, you can't be lazy. Speed is fun, but if the comfort level goes way down to achieve this it gets a bit naff pretty quickly.
To apply this to the real world... Graeme and I are headed for same harbour and its been a bit fresh. Graeme may get their a tad later but he'll be dry, comfy, sporting a big smile and a hairstyle like he stepped out of Vogue magazine. I might get there a bit quicker, but I'll be soaked, tired, counting bruises, sporting a HUGE smile and a hairstyle like I stepped out of Just Mechanics.
Cheers!
SB


Good writing SB - got a kick out of reading it
JakeNN
JakeNN
372 posts
372 posts
15 Jul 2020 10:10pm
shaggybaxter said..
To answer your question, yes its the best feeling in the world to sit back when the boat is trimmed, on the plane and it' s effortlessly soaking up miles.


I have had a short planing experience on a 50ft yacht and I have to agree it was amazing ... a similar amazing feel to windsurfing.

Thanks SB ... I have got so much to learn!

So planing on a 50 ft knot is not really as easy as it looks on youtube! hmmm .. and I'm sure it doesn't come cheaply either!
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