40' Required for Circumnavigation

[smj]

Originally Posted by Ian McD

I have just gone through this discussion again with much dissappointment. It's a bit like the Chevy v Ford guys. A Little knowledge and a lot of 'don't want to know' ' with a fair bit of ignorance added for interest. All very entertaining but not a lot of help to the poor sod who asked the question. The question has been answered several times by ref to real info but all this seems to be ignored. In several instances, ignorance is exceeded by bad manners. There is no question that all things being equal, bigger is better. There is no question that a keel boat, properly designed, has more chance of coming through that ultimate storm right side up. Accept it and move on. It is very simple high school physics. From there we can go into to the design of each type and make both as safe as they can be given those defining characteristics. Horses for courses.

Hmmm, in the 1979 Fastnet race there were quite a few monos that rolled and lives lost. There was also 2 Prout catamarans that sailed through the middle of the fleet completely unharmed, that means floating right side up. At the end of the race the owner of one of the Prouts stated it was a little beastly out there.
Whoops I guess high school physics didn't hold true that time!

[harlie]

Have to say – I’m a bit disappointed. As someone who is contemplating upgrading to a cat in the 38-44’ range, I picked this thread up hoping to get some valuable info – instead we find a slanging match on mono V cat – again.

[owengg]

When I started the thread I was hoping folks would pat me on the bottom and tell me everything would be ok on a catamaran that I could actually afford in the 35 to 38 range. Personally I like many of the qualities the cat has to offer like space, sailing mostly flat, shallow draft, etc.

I think my answer is that nothing is safe, not even driving to the marina! I suppose one just has to go for it and try to offset the risks with provisioning, planning, experience, and skill no matter what type vessel. Buy a boat you like and can afford and know or learn its limits.

[Jimbo485]

Yep, that is it, Owen!
The rest is just little details.

[downunder]

Originally Posted by owengg

What size catamaran is needed for a circumnavigation? I've read of the dangers of pitch polling in catamarans. From what I've read a circumnavigation shouldn't even be attempted in a boat under 40 ft.

Why are monohulls under 40 feet considered safer? The physics don't make much sense to me.

I think the question has been answered. Pitchpolling is not an issue with modern cruiser designs although was certainly an issue with racing cats.

The monohulls under 40ft are safer is certainly a very debatable issue where agreement will not be reached in these forums. Get a copy of Seaworthiness : The Forgotten Factor by C. A. Marchaj one of the definitive works on the subjective.

He has great reservations about many modern monohull designs.

[Paul L]

Originally Posted by 44'cruisingcat

You guys....

There are several designers who draw cruising boats that SAIL. Like Chris White, Kurt Hughes, several Aussies such as Bob Oram, Geoff and Craig Schionning, and many others. Their CRUISING boats sail to windward as well as or better than the vast majority of mono's My boat simply eats mono's to windward - any CRUISING boat to 50 feet is so easy it's almost funny to watch their expressions of amazement.
....

44,
Do you have any links or can you post some polars for these Cats? I'd like to see some hard data on how close to weather they sail at design weights.

I have no dog in this fight, so 'you guys' doesn't really apply. Just interested in what some of the better cruising cats can these days.

[hoppy]

Originally Posted by colemj

Don't have a collection - just googled "capsized sailboat". The results came back with 3 pictures of Volvo/AC-type racing cats and the rest were monos. Interestingly, a search for "sunken sailboat" just turns up monos.

Anyway, I was responding to the person who categorically stated that "A cats most stable position is upside down. A monohulls is right-side up..." He didn't differentiate anymore than that.

And going back to that google search thing - by far, the vast majority of pictures for both capsized and sunken boats were powerboats!

Mark

[andreshs1]

There are a series of videos blogs in youtube of a young couple that were doing the round the world trip on a Lagoon 380s,
Lovely cat!!
search for Honeymoon, lagoon 380s

Regards

[Sand crab]

I thought I'd post some pics of overturned monos but couldn't find any. Then I realized that they're all on the bottom of the ocean.

[Jimbo485]

Like this one, Sand Crab?

Like this one, Sand Crab?

She has a bit of a heel, but hell, she is still upright and still anchored. I even checked her anchor - being a good neighbor and all that - the anchor is well dug in and she shouldn't drag anytime soon in my opinion. But I could be wrong...

[barnakiel]

Originally Posted by Ian McD

(...) There is no question that a keel boat, (...)

"...Déjà vu is the experience of feeling sure that one has already witnessed or experienced a current situation...".

Source: Wikipedia. ;-)

Now seriously, there are many questions. Catamarans are also keel boats, for one. They are even more keel boats than monos since they have two keels. That the hulls are not ballasted is another issue and that ballast does not equal stability nor safety is yet another. I, for one, have never seen any commercial craft built with a long keel that would have a heavy lead blob at its end. WHY?

There is a graph somewhere up the line, it is good to look at the vanishing stability, then it is also good to look at the righting moments. Which boat is safer - the one that will not capsize or the one that will capsize and come back?

And WHY?

In fact, there are many questions. By asking and addressing them we can move this world, and this thread, forward.

Cheers,
barnie

[sarafina]

Play Nice(er) Please.

[estarzinger]

This by shuttleworth is worthwhile reading.

[Sand crab]

Originally Posted by barnakiel

"
There is a graph somewhere up the line, it is good to look at the vanishing stability, then it is also good to look at the righting moments. Which boat is safer - the one that will not capsize or the one that will capsize and come back?

One should also ponder which boat is safer......the one with 4 tons of lead at the bottom which might free itself from said boat or the one that heels over at 90 degrees in high seas and wind and won't come back up because the waves are crashing on the rig or the one where the crew are so exhausted from being in the dramatically heeling boat for days in this storm that they can't get any sleep and make a very bad decision like slipping off the boat or the one where the scalding pot of liquid flies off the stove and gives the crew severe burns.......I could go on

What I'm trying to say that argueing mono vs multi is pointless. They both have their good and bad. BOB

PS Yeah, like that one Jimbo

[alan_za]

In general the larger a cat is the more seaworthy it is, since the goal of a cat is not to capsize ever. That is not to say a small cat can't be seaworthy, but you definately have to be more careful.

With mono's it's more complicated since there are a number of factors (ignoring hull shape) which influence it's seaworthiness; loa, beam and keel weight to displacement -all of which contribute to 1)not capsizing and 2) righting after a capsize.

Only one of these factors, loa, falls under the larger is better rule.