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Old 24-10-2012, 06:21   #121
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

A French sailor arrived in my marina today. He sailed a 11 meter long catamaran around the world in 152 days. Average speed was 9 knots. During the trip he hit a very big storm near Australia and his boat was the only one that didn't sink. He ran from the storm with the wind at the stern and pulled warps. He strongly recommends that cleats be strong to hold the warps or Jordan series drouges since both his cleats were ripped off the boat during the storm. He had to resort to holding a line to the winch.
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Old 24-10-2012, 06:33   #122
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Quote:
Originally Posted by carstenb View Post
(...)

How about getting to the other end of the passage and the worst that happened was spilling my sundowner?

You lucky duck catamaran owners!!!

;-)

Or was the lake placid on that specific day?

;-))

Love,
lippy b.
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Old 24-10-2012, 06:58   #123
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Re: Beamy boats more resistant to capsize ? Well.... not necessarily

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Originally Posted by barnakiel View Post
Well, if the beam is more than the breaking waves are tall (say you are sailing a lake), then you are safer (than in a narrower boat). But what if they are not? (say you are sailing an ocean)

E.g. remember that the beamy boat will have her lee deck sunk deeper in the wave - and more bottom area exposed to the rolling water - both factors may contribute to a deeper capsize.

I think, in real life, boats are unlikely to capsize or get rolled 360. When they are, both types (narrow/beamy) will do so equally - the beamy ones then are more prone to stay inverted for longer (some - for ever).

It is far more common however for boats to get badly knocked down (flat, or mast in the water). When sea conditions are bad like this, my personal experience says (along with some reading of accident accounts) that the narrow boats are knocked down more often but they seem to recover better while the beamy ones have fewer but more severe wipe outs.

It is all a long and involved story and can be viewed from so many angles that in the end probably everybody is right. This has been proven in many a thread at CF ... ;-)

Narrow or beamy, make sure that if you are crossing waters where such a wave can exist, your boat is prepared to get wiped out, capsized and rolled 360 - and that she will recover.

Cheers,
b.
The short answer is that it takes more to capsize a beamy boat. They are much more stable than the narrower hulled boats, BUT once capsized, they (many times) cannot be righted. Whereas a boat like a Cape Dory 30 (9' beam) or a Bristol 27 (8' beam) will roll right back upright. For example, on the Bristol 27 total displacement is 6600lbs with 2500lbs being in the keel.
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Old 24-10-2012, 07:51   #124
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Thomm225

Further up this thread is a link to USSailing website with a capsize calculator. It shows an inverse relationship between wide of beam and stability (bigger beam - less stabile).

Barnakiel - Mulithull Please! I drive a mono. But spilling my sundowner is bad enough
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Old 24-10-2012, 08:32   #125
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

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Originally Posted by carstenb View Post
Thomm225

Further up this thread is a link to USSailing website with a capsize calculator. It shows an inverse relationship between wide of beam and stability (bigger beam - less stabile).

Barnakiel - Mulithull Please! I drive a mono. But spilling my sundowner is bad enough
This from boat designer Ted Brewer:



<LI class=g>




Good Old Boat - Is your boat stable? article

www.goodoldboat.com › Reader ServicesArticlesCached - Similar

A simple way to design a boat with greater form stability is to increase the beam....

<LI class=g>

<LI class=g>Form stability




A simple way to design a boat with greater form stability is to increase the beam, but this can create problems of safety if carried to excess. The stable hull always tries to remain parallel to the water's surface, but if that surface is the face of a great wave at an angle of 50 or 60 degrees to the horizon, then the super-stable boat is definitely in trouble (see Fig. 6).
Light-displacement craft with overly generous beam may be almost as stable upside down as they are right side up, like Huck Finn's raft. If they are rolled 180 degrees in extreme conditions of wind and sea, they may not right themselves, or they can right so slowly that the hull fills with water through hatches, vents, and other openings. When the boat eventually does right itself, it may well be in a dangerously swamped condition.
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Old 24-10-2012, 11:05   #126
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Re: Beamy boats more resistant to capsize ? Well.... not necessarily

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Originally Posted by thomm225 View Post
The short answer is that it takes more to capsize a beamy boat. They are much more stable than the narrower hulled boats, BUT once capsized, they (many times) cannot be righted. Whereas a boat like a Cape Dory 30 (9' beam) or a Bristol 27 (8' beam) will roll right back upright. For example, on the Bristol 27 total displacement is 6600lbs with 2500lbs being in the keel.
Maybe we can avoid short answers in general discussions (time and space at CF allowing). I would propose that in flat water and all other things equal, it may take more force to capsize the beamy hull. (?)

But oceans are not flat water, and most sea going boats are ballasted and the ballast adds not only righting moment but also roll inertia.

So to say, I think there is a huge gap between static capsize forces (e.g. trying to capsize a boat with a crane pulling on her keel - see VG capsize tests) and dynamic forces as present once the sea is covered with waves (some of them breaking) and the boat is under way (in many directions!).

Marchaj's book explains some of the factors but I know there is a newer book on the subject yet to be devoured by my humble self.

Cheers,
b.
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Old 24-10-2012, 11:18   #127
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Okay then, generally speaking a beamier boat is more stable. If I were going to go off shore though (as in way off) , I would rather be on say a Bristol 27-32 than one of the large catamarans. Folks have flipped those things off shore before and had to stay living in them inverted until help arrived.

Tom

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Old 24-10-2012, 11:33   #128
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

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Originally Posted by thomm225 View Post
Okay then, generally speaking a beamier boat is more stable. If I were going to go off shore though (as in way off) , I would rather be on say a Bristol 27-32 than one of the large catamarans. Folks have flipped those things off shore before and had to stay living in them inverted until help arrived.

Tom

Bristol 27 #335
Doh. I have sailed both types of boats offshore. A cat beats mono hands down: the comfort, the ability to go on in light airs, the condition of the crew that does not get tossed about 24/7.

Our boat is very similar to yours. She took us in relative safety rtw (only one bad knock down - perhaps 135 degs or thereabouts). A 27' cat would be probably less safe. But things do change once one steps up to a bigger boat.

Cheers,
b.
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Old 24-10-2012, 12:56   #129
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

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Doh. I have sailed both types of boats offshore. A cat beats mono hands down: the comfort, the ability to go on in light airs, the condition of the crew that does not get tossed about 24/7.

Our boat is very similar to yours. She took us in relative safety rtw (only one bad knock down - perhaps 135 degs or thereabouts). A 27' cat would be probably less safe. But things do change once one steps up to a bigger boat.

Cheers,
b.
I raced small catamarans for about 15 years. Best speed was 23 knots on a 17' singlehanded catamaran with spinnaker and high aspect ratio main sail! (see NACRA F17)

So, one good thing about the cats (and that includes the big ones) is that you should be about to pick and choose the weather and sea conditions you want. If I had a full crew, I'd probably go with a big catamaran. A few years ago during that large size RTW Catamaran race they were averaging 600 plus miles per day and " driving" around the weather systems.

This video is of Play Station which was one of the boats in the race:

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Old 24-10-2012, 13:30   #130
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Back to the smallest - there is that Swedish guy who built his small boat and now he has been sailing her. Never met, but anyways he is inspirational:

http://www.nuriadevilanova.com/img/peter-pan.jpg

(You can read some of his story just hit google translate)

Just thinking how inventive - the simplest boat, the fewest things to break and the maximum of ocean time! Some idea.

b.
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Old 24-10-2012, 13:38   #131
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Yep, and then there's Hannes Lindemann who crossed the Atlantic (the second time) in a foldable 17' Klepper Kayak.

Book Review: Alone At Sea
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Old 25-10-2012, 01:25   #132
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Thomm225

Notice that your quote from that book says that when faced with a wave that puts the boat at a 50-60 degree angle to the horizon, the beamier boat gets more unstable.

50-60 degrees is what happens when hit by a breaking wave beam on...........
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Old 25-10-2012, 01:44   #133
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Thomm225

A few thousand words up this post, someone (I think it might have been me) made the point that "form stability" helped avoid capsizes due to wind force in waters sheltered from oceanic waves. Racing dinghies capsize in this mode, if the people sailing them have any sense of place.

Whereas form stability makes things worse in respect of capsizes due to wave action in high seastates (which is the sort of capsize deep-sea sailors are concerned with).

Which means that the curves of righting moment (which are based on the water being horizontal) are of little interest in evaluating safe options, unless you're looking at a multihull, or a mono so radically
beamy it qualifies as a monomeringue :-)

Your statement "The short answer is that it takes more to capsize a beamy boat." is short by one word: if you inject the word "wind" after "more", it's a reasonable simplification.
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Old 25-10-2012, 02:19   #134
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

carstenb

A while ago you asked if I had any thoughts about running off. Work got temporarily in the way...

IN the context of a thread which has turned into a discussion about capsize, it can safely be assumed that for one or more of any number of reasons, running off is not a happening thing, for any sailor considering these issues.

In other words, for anyone looking down the barrel-roll of a capsize gun.

Possible reasons for being side-on to a big one might include:

1) Boat broached

2) Something in the way: (a) thin water (b) no water (c) movement of water in dangerous direction) (d) big ship (e) other .......

3) Something stalking (Tropical Revolving Storm, for instance, providing incentives to exit the dangerous quadrant)

4) Steering failure

5) Unexpectedly large wave while reaching

6) Mythical "cross sea" while running - a rogue wave running across a high established wavetrain
(I'm a bit sceptical - I wonder if they're more of an optical illusion, because it seems to me rogue waves rely on the summation effect, where, by a statistical freak, a whole bunch of underlying wavetrains peak at the same time and place -- to me this implies they're all travelling in the same general direction or in opposition. I've certainly never seen a single big cross-sea)

7) Pyramidal seas (these on the other hand are relatively common, and tough to handle -- sort of thing you get when the forecast says "4m swells from the NW, 5m swells from the SE, and 6m swells from the SW", and the mere words conjure up the unique feeling of vomit rising towards your gorge.

The worst seastate I've encountered so far (as luck would have it, in the smallest yacht I've ever sailed offshore) was mercifully remarkably regular.
The waves were perfectly formed and evenly spaced (albeit at least 3x too close together) so it was a smooth ride, albeit a wild one.
Their direction put us in a bit of a quandary, because we had problem 2(b) to leeward and problem 2(c) where we were going.

So we found ourselves reaching, (VERY fast considering the size of the boat) almost as high as a beam reach -- the least desirable point of sail -- towards a location where the seas were inevitably going to become more inclined to break.

We had no choice, because all other points of sail were either suicidal (eg running off) or impossible (eg turning back, or alternatively trying to claw upwind).
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Old 25-10-2012, 02:50   #135
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Re: What is the Smallest Boat That You Would Sail Outside of Coastal Waters?

Andrew,

I can agree with your points but I guess I was speaking in terms of blue water (i.e. no low water). And I was thinking about doing something BEFORE you broach.

While I've never experienced it, my personal thinking is thatI'm better off running, with warps or a drogue that battling it out with a sea anchor (ala Pardley).

Having said all that, We are planning to start our circumnavigation in about 2-3 years (getting the boat ready now). I'm sincerely hoping that when we get all the way around, I'll be able to say that the worst weather we encountered as gale strength. But I will be ready to handle much worse.
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