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RabidRabbit 25-01-2013 20:15

Knocked down 90 degrees
 
Correct me if I'm wrong. If I plan to sail all over the planet for 40-50 years. At some point it should be expected that a knock down will occur, even with the best weather windows, a storm at sea is unavoidable. So wouldnt the vessel choice for a life at sea be one that pops back up when knocked down 90 degees? Seems like this would be a bigger issue with cruisers, pretty much a deal breaker for me. I cant imagine being in any bad weather and wishing I was in a cat.

cwyckham 25-01-2013 20:23

Re: Knocked down 90 degrees
 
Having a boring Friday afternoon and decided to go for a little troll, did we?

The vast majority of monohull round the world cruisers never get knocked down. It's a lot harder to knock down a cat. They virtually never go over, and then gross user error can often be blamed. Some very narrow designs may be an exception.

If I could afford it, I'd sell my mono for a sporty cat and cruise in that. Many would. Many do. I would have no issue whatsoever being in bad weather in a cat, and I'd be a hell of a lot more comfortable than in a mono.

bobconnie 25-01-2013 20:29

Re: Knocked down 90 degrees
 
:whistling:We have sailed for ver 30 yrs in mono hulls, quit counting NMs years ago at 40,000 + never been knocked down yet !! any amount over normal !! I thik ya got things a little slanted !! shorten sail before ya need to !!

boatman61 25-01-2013 20:32

Re: Knocked down 90 degrees
 
Had a coupla 90* knockdowns over the years... last one was in a 53ftr last year.. F7-8 on the beam and the cross sea's just happened to catch us right... crew injured and my coffee spilled...:banghead:
bitta damage but cosmetic mainly..
It happens to most voyagers sooner or later if your getting the miles in.. no big deal...:D
A 360 however is a whole different ball game..:p

DeepFrz 25-01-2013 20:49

Re: Knocked down 90 degrees
 
Quote:

It's a lot harder to knock down a cat. They virtually never go over, and then gross user error can often be blamed.
Do you ever wonder why all production Cats have an escape hatch in the hulls? Have you never seen pictures of the crew of a cat clinging to the underside waiting rescue? I happens more than you realize.

RabidRabbit 25-01-2013 21:00

Re: Knocked down 90 degrees
 
I'm not trollin for nothin, This is a real issue, if its not what your looking for please feel free to sail right by.

I had come to beleive from my library of 60s & 70s cruising books that the knock down was something that hapened to everyone.

sww914 25-01-2013 21:04

Re: Knocked down 90 degrees
 
Quote:

Originally Posted by RabidRabbit (Post 1139714)
I'm not trollin for nothin, This is a real issue, if its not what your looking for please feel free to sail right by.

I had come to beleive from my library of 60s & 70s cruising books that the knock down was something that happened to everyone.

My boat went through 3 hurricanes in the 70's. With today's weather forecasting there's no need for that anymore. I plan to never get knocked down.

cwyckham 25-01-2013 21:06

Re: Knocked down 90 degrees
 
Quote:

Originally Posted by DeepFrz (Post 1139707)
Do you ever wonder why all production Cats have an escape hatch in the hulls? Have you never seen pictures of the crew of a cat clinging to the underside waiting rescue? I happens more than you realize.

The escape hatch just makes sense. Of course, it's possible for them to go over and you need to have a hatch. That's sort of like asking if I know why commercial aircraft have rescue slides. They need them. Doesn't mean that I hesitate to fly just because there's a safety slide installed.

Jim Cate 25-01-2013 21:49

Re: Knocked down 90 degrees
 
RRabbit, I'm not sure exactly what you are looking for!

However virtually any ballasted monohull will rapidly recover from a 90 degree knockdown. There is a parameter called AVS (angle of vanishing stability) which tells you how far over the boat can go and be sure of returning to upright. Most monohulls have AVS values somewhere in the 110-130 degree range. I'm not a naval architect, and the problem is somewhat more complex than as represented here, but that value will give you an idea for any design. Such numbers are always calculated during the design, but are not always shown in the glossy sales brochure. an inquiry to the builder may be necessary.

And to add to the mass of anecdotal evidence: in something over 150,000 miles of blue water and coastal cruising, we have experienced one knockdown to about 90 degrees. I didn't like it. but the boat recovered quickly.

Cheers,

Jim

Jimbo485 25-01-2013 21:50

Re: Knocked down 90 degrees
 
The last time our escape hatch was used involved a female friend who had drunk too much and thought she would lie down in an aft bunk for a while. Suddenly she realised she was going to chuck but she wasn't going to have enough time to get to the deck or the head.

She classified that as an emergency, opened the hatch and spewed her guts out directly into the water.

Very, very lucky we had an emergency hatch!

Jimbo485 25-01-2013 22:05

Re: Knocked down 90 degrees
 
We had a knock down on our previous boat, a mono. We released the sheets and waited a minute (it was a long minute!) for the water to come off the sails and then she popped right back up immediately. No problem. Apart from the mess down below.

cwyckham 25-01-2013 22:25

Re: Knocked down 90 degrees
 
Looks like my stats suck. From our very small sample size, it looks like the sailors who've been cruising monos for many years and many miles get knocked down as far as 90 degrees more than I thought. It would be really interesting to do a real survey like Beth and Evans put together sometimes.

I haven't heard too many cat owners chime in yet.

donradcliffe 25-01-2013 22:28

Re: Knocked down 90 degrees
 
I spilled my cereal once in over 100,000 ocean miles in monohulls. I've had masts near the water in race boats with spinnakers up, but more like 80 degrees than 90. They popped right back up after we got the spinnaker down. On a cruise we don't press the boat nearly as hard as on a race.

roverhi 25-01-2013 22:42

Re: Knocked down 90 degrees
 
The problems with multi-hulls is they reach a point of negative stability or positive stability but upside down. Have a late friend who proved multi's turn turtle. Found his trimaran floating upside down with crew tangled in the running rigging and drowned, no sign of him. Have put the spreaders in the water in the Bay off of SF in a W32. Wind went from a nice sailing breeze to near 40k instantly and subsided back to a nice breeze in minutes. Got a feeling if it had been a multi, would have been able to get a close look at the bottom paint.

That's the reason I'd never sail a cat offshore unless with a full skilled crew that has the quick reactions to dump the main and/or head off when the feces flies. A multi can be blown over without the help of waves. Since I make passages single handed can't rely on a multi to take care of itself. A Mono cannot be rolled except in conjunction with waves, Even then the boat will right itself though probably missing the rig. Still it will be floating upright. A mono will turn up into the wind and dump the wind pressure all by itself in almost all situations. Some people can live with the inverted possibilities of a multi, I can't. Couldn't afford one in any case.

daddle 25-01-2013 22:52

I think you should go out and do a knockdown in controlled conditions. It's a confidence builder. When it happens out at sea in an uncontrolled situation you can then say to yourself "Oh, this again. No sweat."

I've had race boats over 90 degrees on several occasions. This boat blew over to 80 degrees cruising on a nice blustery day with all the white sails flying. Demonstrates and failings in ones stowage plan. Would be dangerous on the typical houseboat cruiser what with the basil plants and grills deployed, dinghies flying around, etc.


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