Question for catamaran cruiser owners

[lw395]

Are you sure about that? Dumping the sail & bearing off will put the sails at right angles to the wind if you had been on a beat.

I'd expect to dump & turn into the wind, but I do realise that there is still a risk of centripetal force lifting the inside hull if you are going very quickly.

You missed the word 'offwind' in my original post, or maybe I should have said 'downwind'?. Upwind, you are right, luff to spill wind.
Downwind, bear off, use your speed to reduce the apparent wind.
It's the same in fast asymmetric dinghies.

 

[oldsaltoz]

If it helps, I have sailing cruising cats for many years and never managed to lift a hull, even on an ex racing cat that was converted to a cruiser.

Of the hire cats sailing in the Whitsunday Islands (Oz) by complete amateurs none have ever flipped or tripped, mind you a few have sand bars and odd rock.

Good luck and fair winds.

 

[wotayottie]

One thing to remember. People fixate with cats on the angle of maximum righting moment which is of course far lower at about 45 degrees than even the lightest keeled AWB. However they forget that the energy required to get a cruising cat of a given length to the angle of max righting moment is way more than for the same length mono because the weight of one cat hull is so far away from the centre of rotation in the other hull. Capsizes usually come not just from the sustained pressure of the wind in the sails but from wave impact transferring energy when the boat is already heeling and the boat tripping over its centre of rotation. A cat has to collect far more wave energy to capsize than a mono of the same length. If you doubt that, have a look at some graphs of righting moment against angle of heel.

This is why cruising cats usually have shallow keels ( makes sliding sideways under pressure easier) and its also why resistance to capsize in cats goes up as the cube of the loa and not simply in proportion to it.

 

[Tomahawk]

I would like a large cruising cat one day, and I understand they have to be watched all the time (not auto pilot and make a cuppa on a windy day).

Thanks

Tim

You have very good and very expensive taste.... A Gunboat 60 is carbon fibre and epoxy all over... and undr and inside /outside Etc.. They are not your average cruising cat.. In racing mode it is fully crewed and pushing hard.. in cruising mode a reef.. loose two or three knots and still overtake everything on one hull.. ( except a Volvo 70)


Would love one myself ... but don't have that much..

 

[Tropic Cat]

....This is why cruising cats usually have shallow keels ( makes sliding sideways under pressure easier) and its also why resistance to capsize in cats goes up as the cube of the loa and not simply in proportion to it.

This is all correct and the reason why I own a catamaran with an underwater profile which slips sideways in gusts. Dagger board catamarans are terrific performers, but you have to sail with a hand on the main sheet.

 

[Tomahawk]

My Outremer has dagger boards..

I was told by one of the designers, if it accelerates in the gusts you are OK.

This seems to make sense.. Unlike the Gunboat which is extremely light, mine (and most cruising cats) is too heavy to get a hull right out of the water without pushing the other one deep in as all the buoyancy is now coming from one hull.. As that hull is pushed deeper in the water it produces more drag... and if very bad the bow starts to dig in... this stops her accelerating .. hence the warning note ... it is past the time to reef... I have found, however, that once reefed we do not slow down much..

If you do buy Gunboat... Can I come out to play? (pretty please..)

 

[Tomahawk]

http://www.youtube.com/watch?v=JihMSktupkY&feature=player_detailpage#t=1s

This chap is by himself.. He is French which does explain a lot... but you can see he is on autopilot and does not have his hand on the mainsheet in expectation of going flip...

It would be an interesting runoff between the Gunboat and this Outremer 50.. The Gunboat certainly has it on speed alone but the Outremer seems more forgiving..