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Old 16-05-2015, 16:20   #106
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by Canibul View Post
I don't understand your point about Catalacs. Isn't the subject flipping cats over? Here's a design nobody has ever flipped over, and your response is to dismiss that , mention something else entirely and then say you're introducting a "more positive note" about bridge deck slamming?

Again, what has this got to do with capsizing? Seems About as apropos as the gel coat color or what type of anchor it's carrying.

This thread is starting to remind me of the people who will try to explain to you that some un named one else somewhere calculated that a bumblebee cannot fly. Therefore it must be true.

Do catamarans south of the equator flip to right side up? I've been thinking of getting me some of those logging boots with the spikes so I can keep on the top of my rapidly spinning catamaran.
After your previous post I found this which a great read. Affordable Cruising Catamarans I like the author. Honest chap who seems very happy with the virtues of the catalac.

The rudder on the skeg assisting point angle was quite an interesting highlight also acting like a wing.

As he says. Bit of a f&*k up when they thought up the name. Was never gonna win favour easily in the US with that name.

Interesting stuff.
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Old 16-05-2015, 17:02   #107
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Re: Is there a catamaran of cruising size that can self right unaided?

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To some extent it is a question of luck whether you get caught in wind of 50kts, 60kts or more.
Obviously, if you can't handle a cat in 50-60kts of wind and you never see such, you can classify it as luck. Personally, I've been there done that, never questioned my ability to handle the boat, nor the ability of the boat to handle the conditions. The only thing that pissed me off is getting caught in such conditions.
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Old 16-05-2015, 17:11   #108
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by Juho View Post
Here's my plan for saving a catamaran that has turned upside down (single-handed, in the middle of an ocean).

I have a rescue package that consists of some large inflatable balloons and rafts. First I move one of the balloons to the top of the mast (maybe using a halyard) and fill it up. If the mast is strong enough to turn the boat upside down, it may be strong enough to turn it also back. When the mast floats again (horizontal) I put some additional rafts below it and fill them. At some point the boat will turn itself upright again. Done.

P.S. I might use that rescue package also to save a sinking monohull (fill the balloons inside the hull).
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Old 16-05-2015, 18:11   #109
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by DerekKelsall View Post
Hi,

The challenge of self righting a capsized catamaran is not as difficult a task as perhaps first perceived. We spent a lot of time on safety issues in the early days of my design career. It does have to start at the design stage.

Thirty years ago we built a 36ft. cruising catamaran which we capsized on a lake in Sandwich in Kent. The righting system was automatic to a large extent, invented by the owner Gunther Ulrich. Capsized she floated on the saloon top and the bows. Valves in the bows were opened and she began to rotate. The secret is to arrange for the buoyancy to remain offset from the center of gravity as she rotates to flip past the 90 degrees. At that point the rotation continues with the water flowing out of the bow compartments. Stopping at about 30 degree from full floatation, then pumps are employed.

This system was on similar to one we had previously fitted to a tri. which involved pumping all of the water. Gunthers system depended on no floatation built into the bows, which would be too much of a compromise for most cat owners. The system we used on the tri (not tested) applies equally to a cruising cat, with relatively little compromise or cost in the overall picture. Flotation needs to be positioned to provide the axis of rotation and water tight doors etc. Obviously, this is not dependent on the rig being in place. We got so little interest at the time, we did not take further.

However, with a few cat losses recently we are considering going back to offering this and the survival compartment design we can also offer. There is very little compromise to arrange an aft cabin for survival.

Yes - what about big seas etc. Some day perhaps a cat will capsize and sail home - and then we will know.

Happy boating,

Derek.
Keep me updated on this please..
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Old 16-05-2015, 18:15   #110
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by DerekKelsall View Post
Hi,



The challenge of self righting a capsized catamaran is not as difficult a task as perhaps first perceived. We spent a lot of time on safety issues in the early days of my design career. It does have to start at the design stage.



Thirty years ago we built a 36ft. cruising catamaran which we capsized on a lake in Sandwich in Kent. The righting system was automatic to a large extent, invented by the owner Gunther Ulrich. Capsized she floated on the saloon top and the bows. Valves in the bows were opened and she began to rotate. The secret is to arrange for the buoyancy to remain offset from the center of gravity as she rotates to flip past the 90 degrees. At that point the rotation continues with the water flowing out of the bow compartments. Stopping at about 30 degree from full floatation, then pumps are employed.



This system was on similar to one we had previously fitted to a tri. which involved pumping all of the water. Gunthers system depended on no floatation built into the bows, which would be too much of a compromise for most cat owners. The system we used on the tri (not tested) applies equally to a cruising cat, with relatively little compromise or cost in the overall picture. Flotation needs to be positioned to provide the axis of rotation and water tight doors etc. Obviously, this is not dependent on the rig being in place. We got so little interest at the time, we did not take further.



However, with a few cat losses recently we are considering going back to offering this and the survival compartment design we can also offer. There is very little compromise to arrange an aft cabin for survival.



Yes - what about big seas etc. Some day perhaps a cat will capsize and sail home - and then we will know.



Happy boating,



Derek.

Thanks for the rare and informative post Derek
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Old 16-05-2015, 18:52   #111
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Re: Is there a catamaran of cruising size that can self right unaided?

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You could not use the mast as it would be too congested but you could use the shrouds and run the balloons to top of the mast that way but I am useless at doing knots in balloons and run out of puff after a couple.

I would just run back and forward on the top like Jack Sparrow did. That worked.

Joking aside there is some merit in what Juho says if you could get a big lift bag being pulled down against a shroud somehow.

But I would use big water bags kept underneath and would put these out side of one hull then attach one end of my carbon fibre rope that I also keep under the bridge deck to the bags and the ends to the other side of the hull then would winch them on board evenly using my pulley ratchets. I am right in thinking the underneath of the bridge deck is a cats boot, trunk for you Americans where you keep your tools? 4 x 5 cubic metre bags should do the trick.
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Old 16-05-2015, 19:35   #112
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Re: Is there a catamaran of cruising size that can self right unaided?

An idea from Tony Bigras

Osram VII Design for Righting after Capsize



Quote:
I have no plans to test the righting method before there is an actual need. However it seems prudent to pay attention to the design details during construction given that they can provide a theoretical option for self rescue at negligable extra cost. The centers of gravity and bouyancy and the physics say it should be doable.

That said here is how it is supposed to work.

First off we plan for a bit of habitability when upside down. Just relying on the foam insulation/floatation it should sit about with the deck about 12" underwater and slightly bow down. There is an access hatch at the bottom of the wet locker to get out onto the bridge deck. Tie points are in place to rig hammocks to get out of the water down below. A few waterproof flashlights are kept below. The fuel and batteries are all out in cockpit lockers and any leakage should stay out there.

When the weather is ok for righting we give it a try.

The actual righting method involves stern over bow righting. The bows are flooded and submersed which puts the stern into the air, then the stern is pulled down to the surface. At that point the bows are bailed out. Everything get soaking wet but we are right side up.

If the mast is still up (down) when capsized it helps the righting effort with its sealed bouyancy, but it is not critical.

The forward sections are not foamed so they are easy to flood and when flooded the mast should bring itself to the surface. Getting the rest of the way requires a lever and some weight. The lever is the catwalk/boarding_ladder/righting_lever. The weight is just a bunch of 4 gallon emergency_bouyancy/water containers I normally carry in the bows.

About 50 of these tied together provied the weight. The catwalk is unpinned from its pivots up forward and connected to the pivots on the underside of the bridgedeck. The anchor windlass is on the catwalk and is a spooling ratchet type ( sorta like a huge trailer winch ) and provides the purchase via a 2/1 block at end of the cockpit. Swell action should help with the takeup being done as the swell lifts the floating containers.

Extra stuf for the contigency includes:

Pivot points welded on for the catwalk.
A couple of permantently rigged blocks.
Making the wetlocker drain also removable.
Hardpoints welded in for the hammocks.
Multi use 4 gal containers ( used cooking oil jugs about 50 cents each )
Using fastpins rather than bolts for the catwalk pivots.
Non skid and harness tie points on the underside of bridgedeck.

I worked on a 40' production cat in El Salvador in 1978 with this designed in ( never got into production ) and also included it on my 23' cat. It is just a simple bit of low cost planning for a bit of peace of mind for the most part I think. One nice aspect with the use of aluminium is that it is easy to adjust the flooded center of bouyancy with the placement of foam.
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Old 16-05-2015, 20:00   #113
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Re: Is there a catamaran of cruising size that can self right unaided?

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Thanks for the rare and informative post Derek
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Old 16-05-2015, 20:02   #114
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Re: Is there a catamaran of cruising size that can self right unaided?

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We had F11 - F12 in the Med this week.

I have had 183km/h in my marina in the South of France a few years back.

In both cases I was glad to be at home in my solid steel reinforced concrete house.
Don't be a knucklehead. I say something simple and someone has to run with it. We are talking about hurricane sea states, which any boat may founder in, not coastal storms. Heck, I've had a beach cat out on 70 knots (reported at the CG station 1/4 mile away) and managed by feathering. Big deal. I've seen 60 knots in squalls many times in my PDQ and not even felt excited.

Yes, home is better.

----

These threads are so pointless. Most of us would consider getting caught in a dangerous (definition varies with the boat--duh)storm an act of poor seamanship, because we have no interest in crossing oceans and weather forecasting is good. So for most of us, owning a hurricane-proof high latitude boat makes as much sense as driving a Hummer; none at all. Wouldn't want one.
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Old 16-05-2015, 21:12   #115
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by DerekKelsall View Post
Hi,

The challenge of self righting a capsized catamaran is not as difficult a task as perhaps first perceived. We spent a lot of time on safety issues in the early days of my design career. It does have to start at the design stage.

Thirty years ago we built a 36ft. cruising catamaran which we capsized on a lake in Sandwich in Kent. The righting system was automatic to a large extent, invented by the owner Gunther Ulrich. Capsized she floated on the saloon top and the bows. Valves in the bows were opened and she began to rotate. The secret is to arrange for the buoyancy to remain offset from the center of gravity as she rotates to flip past the 90 degrees. At that point the rotation continues with the water flowing out of the bow compartments. Stopping at about 30 degree from full floatation, then pumps are employed.

This system was on similar to one we had previously fitted to a tri. which involved pumping all of the water. Gunthers system depended on no floatation built into the bows, which would be too much of a compromise for most cat owners. The system we used on the tri (not tested) applies equally to a cruising cat, with relatively little compromise or cost in the overall picture. Flotation needs to be positioned to provide the axis of rotation and water tight doors etc. Obviously, this is not dependent on the rig being in place. We got so little interest at the time, we did not take further.

However, with a few cat losses recently we are considering going back to offering this and the survival compartment design we can also offer. There is very little compromise to arrange an aft cabin for survival.

Yes - what about big seas etc. Some day perhaps a cat will capsize and sail home - and then we will know.

Happy boating,

Derek.
Sounds like a neat idea. I bet someone can figure out how to create flotation that can be released or retracted towards mid hulls when a catamaran goes inverted.
That would be a major selling point for those very cautious types out there.

Hey folks! It's Derek Kelsall! Designer par excellence!
Thanks for posting and please beef up your post count. We want to hear more about your thoughts on multihulls.
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Old 16-05-2015, 23:22   #116
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Re: Is there a catamaran of cruising size that can self right unaided?

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I do not know a great deal about catamarans except that they make me a little nervous.

I have read the pro catamaran argument that says a cat will not sink if capsized which is all well and good but the probability of a catamaran capsizing far outweighs that of a mono sinking.

I wondered if there is any technology that has dealt with and solved the problem of righting a catamaran hull unaided by external assistance while at sea.
We've flipped our boat thousands of times. We must have according to the experts on here. Gets so you don't even notice.
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Old 17-05-2015, 00:20   #117
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Re: Is there a catamaran of cruising size that can self right unaided?

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You are completely wrong. Go and get a quote to sail to the artic in a 40 foot cat and a quote for the same journey in a mono. For the same values from the same company.

I've had insurance for open ocean sailing on a mono and a cat. If anything the cat's premiums, in percentage terms, are CHEAPER. I'd assume that was mostly because the cat has a higher value. There were no restrictions on where I could go.

To say the risk of a cat capsiszing is higher isn't borne out by the facts. A mono can sink in a marina berth on a perfectly calm day.

I'm another who'd like to see the numbers you're using.
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Old 17-05-2015, 00:41   #118
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Re: Is there a catamaran of cruising size that can self right unaided?

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"Most sailors agree that the mainsail, particularly the large roached, full battened mainsail combined with the aft-led-shroud, no-backstay-configuration that is used in most catamarans today, is by far the most troublesome sail to hoist, reef/unreef, furl and cover. In addition, mainsails create significant safety liabilities because they cannot be easily or quickly reefed or furled when sailing downwind. In violent squalls this feature has caused more than a few capsizes. The conventional catamaran mainsail can also be somewhat risky to gybe in a blow."

.
Amazing the Chris White would write such rubbish. Obviously he's selling something.

We routinely reef downwind. Because of the battens and battencars, it's far easier than with our old mono, which was virtually impossible to reef downwind. (The sail would wrap around the shrouds as soon as halyard tension was released.)

Gybing is a piece of cake, again far easier and safer than our old mono, due to the wide traveller track, and higher boatspeed resulting in lower apparent wind.


Pretty laughable that higher lattitudes are somehow seen as tougher. A few weeks ago there were winds of around 150 knots where I am, in the tropics, right now.
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Old 17-05-2015, 02:18   #119
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pirate Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by Juho View Post
Here's my plan for saving a catamaran that has turned upside down (single-handed, in the middle of an ocean).

I have a rescue package that consists of some large inflatable balloons and rafts. First I move one of the balloons to the top of the mast (maybe using a halyard) and fill it up. If the mast is strong enough to turn the boat upside down, it may be strong enough to turn it also back. When the mast floats again (horizontal) I put some additional rafts below it and fill them. At some point the boat will turn itself upright again. Done.

P.S. I might use that rescue package also to save a sinking monohull (fill the balloons inside the hull).
As its 'Flipped'.. would not the top of the mast now be the bottom..
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Old 17-05-2015, 03:28   #120
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Re: Is there a catamaran of cruising size that can self right unaided?

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I do not know a great deal about catamarans
Says it all really
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