On the subject of boating accidents...

[jonhenderson]

Does anyone happen to know the cause/outcome of the catamaran that flipped over just off Calshot the other week?







<hr width=100% size=1>I can't see the whites of their eyes, I'm not tacking....

 

[Boathook]

Don't know. But being a cruising Cat owner and seeing the picture of the one in the Solent it had a dagger board down. As the boat was an Iroquois ? (they sail rings round my cruising cat) they do go occassionally when pushed hard in bad weather. Having written that, I do not know when the last one did flip. I also read that they had only just purchased it so that does not help.
Would I buy one - YES, but my first trip would have to be in the correct conditions or with some one experienced in this type of boat.
These are only my opinions so may be some owners would like to comment?

Now, wheres my book on reefing. Full sail and 25+ knots of wind gives bad leeway ...


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[jonhenderson]

Unfortunately my knowledge of sailing cats is low, recent and coming with experience as the summer weekends go by. I am currently sailing on a friend's Edel Cat 35. He wanted a new adventure and bought a boat. My cat has sailed more than him so I'm teaching him how to sail.

So far so good as winds have never been too strong to feel unsafe.

Last weekend we were on a reach in 13-18kn true and comfortably cracking along at over 10kn. I was loving it he was nervous! Heh heh!!

Anyway, the subject of reefing is an obvious subject for discussion - when is it prudent to do so on a racer/cruiser cat? I have done some net research which has borne little fruit, but for a report written by an owner of and Edel 35 who said he had been in 35kn apparent with full main. Can this be a) true and b) safe?!

Any thoughts for a monohull sailor rapidly being converted to the multi version?!

<hr width=100% size=1>I can't see the whites of their eyes, I'm not tacking....

 

[snowleopard]

every boat is different. i wouldn't sail an iroqois in more than 15 knots of wind with a full main but my 40 footer is quite happy in those conditions.

stability is conferred by size, weight and beam. if you increase everything in proportion the stability goes up with the 4th power of the length so big is beautiful.

i once read the suggestion that you should take your new cat out with an experienced crew on the sheets then, in flat water, drive it till it lifts a hull, then you'll know its limits. personally i'm not that brave!

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[BrendanS]

There was an amazing photo in a Sunday Times magazine some months back, of a large catamaran towing an ex world record holder water skier. One hull must have been over 20' out of the water.

<hr width=100% size=1>Err, let me know if Depsol enters the forum, I'll go and hide

 

[snowleopard]

must be the french...

they do like to fly a hull, or in the case of tri sailors, two.

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[snowleopard]

must be the french...

they do like to fly a hull, or in the case of tri sailors, two.

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[jamesjermain]

But they capsize don\'t they?

May I be permitted to quote from an article I wrote for an American magazine. (excuse length)

In a section titled 'But they capsize, don't they', I said:

'Let's be quite clear about this. The incidence of capsize among modern cruising catamarans is almost nil. Certainly fewer cruising cats capsize then monohulls sink. Ask yourself this: 'Would you prefer to await rescue sitting on the underside of a wide brigedeck with the ship's stores still accessible, or crouched in a tiby liferaft with just the ocntents of the survival pack for comfort?

But if you buy a cat you have to accept that capsize is possible and that righting, without external assistance, is not. Cats, by their nature, give little warning of themoment they are going to flip, even to experienced sailors, so you need some sort of quasi-scientific basis on which to make the vital decision of when to reef. Designers have come up with quite a simple equation, based on the balance of righting forces with heeling force. It gives the wind speed necessary to lift the windward hull in a flat sea (static stability).

(I'm writing this in words cos I don't know how to do a formula in html)
Apparent wind speed = (F(a constant) x the square root of actual displacement x half the beam between the centrelines of the two hulls) divided by (sail area x the height of the centre of effort of the current rig).

The constant (f) is usually taken to be 14 and all figures should be in feet and pounds.

Because the sea is never still, particularly in wind speeds sufficient to capzise a cat, wave motion is a major factor in any capsize, and this needs to be taken into consideraton. If you reduce teh apparent windspeed gtiven by the above formula by a sixth, this will give a safe margin in most sea conditions.'

In practice, most cruising cats can sail safely in winds up to 25 knots before putting in the first reef, around 28 to 30 knots for the second and 35 to 38 for the third/storm canvas.

The full article ran to about 6 pages and appeared in Sail, January 2003 and examined the pros and cons of cats and various aspects of their design.

<hr width=100% size=1>JJ

 

[jonhenderson]

Re: But they capsize don\'t they?

James that's most interesting - I may have to see if I can get hold a copy of that edition.

And get me calculator out too.....!!

That basic rule or thumb looks to be sensible to me too, although an Edel Cat is faster than your average cruiser so it may be able to be pushed a little harder, we shall see.

Jon





<hr width=100% size=1>I can't see the whites of their eyes, I'm not tacking....

 

[jonhenderson]

One further question

How do you work out what the height of the centre of effort on the rig is?

Also assuming a centre of effort as half way up the mast, the formula doesn't seem to work for me? Input data:

Displacement 7000lbs
Beam 20'
Sail Area 720sq'
Height of COE 20'

Output 0.7....?!

Cheers!





<hr width=100% size=1>I can't see the whites of their eyes, I'm not tacking....<P ID="edit"><FONT SIZE=-1>Edited by jonhenderson on 02/06/2003 12:52 (server time).</FONT></P>

 

[jamesjermain]

Re: One further question

Draw diagram of sail plan. Calculate centre of effort of each sail and mark it, draw line between two centres of effort and mark combined centre of efforts as a point along the line proportional to the areas of the two sails.

Sorry, doesn't work in a few words - needs a diagram. It should be about a third of the way up the mast from the gooseneck.

<hr width=100% size=1>JJ

 

[coachone]

Re: But they capsize don\'t they?

I have owned an Edel cat for 5years [could be the one you sail on]

I would make three comments;

1]always judge the correct amount of sail to set relative to the true windspeed in the gusts [not the apparent wind which will be very different, especially when sailing downwind]

2]25kts true windspeed is too much wind to have the full main up, unless you are racing and have a hand on the sheet!

3]cats have lower prismatic [ ie they are more easily driven] than water-pushing monohulls, therefore you don't need as much power, ie sail, to drive them.If in doubt take a reef in.

The mainsail on most cats is the bigger, more powerful, sail and the because of the dynamics is the sail that might cause the boat to nosedive off wind.....therefore reef the main first before reefing the jib.

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[jamesjermain]

Re: But they capsize don\'t they?

The Edel Cat 35 has a fairly big rig and I would suggest itmight need reefing earlier rather than later. If the Edel Cat 35 you are sailing is the one previously owned by Rod Carr and, before him, Geoff Hayles, it has a much bigger rig than standard and definitely needs handling with kid gloves.

<hr width=100% size=1>JJ

 

[jonhenderson]

Re: But they capsize don\'t they?

That is the same boat James yes - Impulse is the name and she's a beauty. I never thought I'd hear myself say that of a cruising cat but she is!

Thanks for the advice - appreciated.

<hr width=100% size=1>I can't see the whites of their eyes, I'm not tacking....