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Old 27-10-2013, 19:42   #91
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Re: 50ft monhull vs 44ft cat

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Originally Posted by Jimbo485 View Post
Jim,

I like your logic, I truly respect your opinions and it hurts me to note this but.......

....... a cat has a huge gap between the hulls where nothing much happens. Only 2 weeks ago, for unimportant reasons, we were in a collision situation with a floating object. A quick glance showed that we did not have enough time/distance to turn away. So I aimed at it. At the last second I made a correction to be sure it went straight down the middle without touching any hulls, props or dagger boards. It passed underneath sin problema.

Doing the mathematical calculations of the the front-on cross-sectional area exposed to a potential collision, I have no doubt that the multis are the least riskiest, as compared to a mono.

Multi-hulls have hulls that are individually very fine and shallow. Multiply that by 2 and it is still sweet nothing.
All very well when considering small, low profile floaters, but how about the dread shipping container? Doubt if it will pass safely through...

But it is all meant as a sort of joke... almost!

Jim
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Old 27-10-2013, 19:59   #92
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Re: 50ft monhull vs 44ft cat

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but how about the dread shipping container? Doubt if it will pass safely through...
If it is floating a couple feet below the surface like many of them do, we will pass right over it unnoticed. Wouldn't want to be in one of those 6' draft thingies, though!

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Old 28-10-2013, 14:51   #93
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Re: 50ft monhull vs 44ft cat

Shallower draught is safer too. We can get into cyclone holes deep draught boats can't.

Several of the boats we met in Bundaberg wouldn't sail south through the Great Sandy straits because of their concerns about draught. They had to go about 50 miles in the wrong direction before turning South and going around the outside of Fraser island. They are far more vulnerable to weather there.

And a guy I met just recently with a deep keeler decided to opt for going outside Moreton / North/south Stradbroke islands too.

We have several excellent, sheltered anchorages we regularly use, that deep draughted boats can't access.
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Old 28-10-2013, 15:13   #94
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Re: 50ft monhull vs 44ft cat

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Back to a same old same old question.
Which one is safer for blue water. Transatlantic.
The one without an idiot as Skipper.
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Old 28-10-2013, 17:35   #95
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Re: 50ft monhull vs 44ft cat

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Shallower draught is safer too. We can get into cyclone holes deep draught boats can't.

Several of the boats we met in Bundaberg wouldn't sail south through the Great Sandy straits because of their concerns about draught. They had to go about 50 miles in the wrong direction before turning South and going around the outside of Fraser island. They are far more vulnerable to weather there.

And a guy I met just recently with a deep keeler decided to opt for going outside Moreton / North/south Stradbroke islands too.

We have several excellent, sheltered anchorages we regularly use, that deep draughted boats can't access.
Well, ignorance is not always bliss! Don't know what draft your friends have, but we are 2.2 metres and have made at least 20 passages through the Sandy Straights. Have personal friends with 2.6 metres who have also made it without issue. It does require watching the tides, but that should not be beyond the skill set of any cruiser.

And re the floating container... IIRC many of them are 40 feet long. Even if floating two feet below the surface, unless you are lucky enough to approach it parallel to its longitudinal axis a strike seems likely.

But we're beginning to sound silly here IMO. The odds of hitting one in any yacht are very very slim, and I stopped really worrying about it a long time and lots of miles ago. We should reserve our worrying strength for important issues like meteor strikes and rats carrying bubonic plague.

Cheers,

Jim
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Old 28-10-2013, 17:47   #96
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Re: 50ft monhull vs 44ft cat

double what doj said......

everyone is different. each feels safe in different circumstances and situations and surroundings.
that is why the gods made so many different kinds of boats....


or was that the aliens... i fergit....

ye know, guys... each time yŠll do this stoopit argument, it gets dummer and dummer.... mebbe that is saying something.....
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Old 28-10-2013, 17:53   #97
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Re: 50ft monhull vs 44ft cat

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But we're beginning to sound silly here IMO.
Oh, I thought we were sounding silly quite awhile ago - I was just playing along for fun!

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Old 29-10-2013, 02:39   #98
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Re: 50ft monhull vs 44ft cat

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Mark,
You are aware that when the victory ships were first launched they broke apart and sank with alarming regularity [and often all hands] due to a faulty design and worse construction techniques aren't you?
The answer though for slow cargo ships is simply cost/ton/mile isn't it not inherent safety?
Cheers,
Mac
If your goal is to move 50,000 tons of bulk cargo, a really big mono is the way to go.

If you are moving 2 people, the math works out a little different.
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Old 29-10-2013, 02:59   #99
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Re: 50ft monhull vs 44ft cat

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An idle thought: has anyone considered that with a beam of around 2 times that of a monohull of similar capacity, the catamaran has about twice the probability of hitting a floating hazard?

I am not sure what this means in terms of real life cruising disasters, but I think that it is mathematically correct.

Cheers,

Jim
Actually the math isn't double the likelyhood of hitting a container, even ignoring the possibility of stradeling with a cat.

If you are approaching a 50' container broadside, with say a 16' beam mono or a 20' beam cat (If your are more than 1/2 the beam off the end of the container you miss it):
- There is a 66' range of headings where the mono will hit the container.
- There is a 70' range of headings where the cat will hit the container.

Hardly double. Factor in stradling, shallow draft, approaching on the narrow end and the silly rareness of hitting a container in the first place and it's really a non-issue.
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Old 29-10-2013, 03:33   #100
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Re: 50ft monhull vs 44ft cat

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Have personal friends with 2.6 metres who have also made it without issue.
They would have an hour either side of high at Sheridan Flats.
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Old 29-10-2013, 08:37   #101
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Re: 50ft monhull vs 44ft cat

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Originally Posted by valhalla360 View Post
Actually the math isn't double the likelyhood of hitting a container, even ignoring the possibility of stradeling with a cat.

If you are approaching a 50' container broadside, with say a 16' beam mono or a 20' beam cat (If your are more than 1/2 the beam off the end of the container you miss it):
- There is a 66' range of headings where the mono will hit the container.
- There is a 70' range of headings where the cat will hit the container.

Hardly double. Factor in stradling, shallow draft, approaching on the narrow end and the silly rareness of hitting a container in the first place and it's really a non-issue.
Killjoy!

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Old 29-10-2013, 09:58   #102
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Re: 50ft monhull vs 44ft cat

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Originally Posted by valhalla360 View Post
Actually the math isn't double the likelyhood of hitting a container, even ignoring the possibility of stradeling with a cat.

If you are approaching a 50' container broadside, with say a 16' beam mono or a 20' beam cat (If your are more than 1/2 the beam off the end of the container you miss it):
- There is a 66' range of headings where the mono will hit the container.
- There is a 70' range of headings where the cat will hit the container.

Hardly double. Factor in stradling, shallow draft, approaching on the narrow end and the silly rareness of hitting a container in the first place and it's really a non-issue.
Comparing a mono with a 16 foot beam and a cat with a 20 foot beam seems not to meet the criteria of vessels with similar capacity...

Further, consider the effect of a mono striking something at a point offset by one third of the beam... this will be a glancing blow with the chance of simply shoving the bow sideways. With a cat, a similar strike at one third of the beam is still a bows on impact on one hull, and this seems a more serious event to me.

But who cares? It is a silly argument over a very unlikely occurrence.

Jim
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Old 29-10-2013, 10:03   #103
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Re: 50ft monhull vs 44ft cat

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But who cares? It is a silly argument over a very unlikely occurrence.

Jim
It is isn't it? But lots of people from the safety of their armchairs like to spend most of their thinking time on the 0.01% odds of stuff happening.
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Old 29-10-2013, 11:55   #104
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Re: 50ft monhull vs 44ft cat

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Comparing a mono with a 16 foot beam and a cat with a 20 foot beam seems not to meet the criteria of vessels with similar capacity...

Further, consider the effect of a mono striking something at a point offset by one third of the beam... this will be a glancing blow with the chance of simply shoving the bow sideways. With a cat, a similar strike at one third of the beam is still a bows on impact on one hull, and this seems a more serious event to me.

But who cares? It is a silly argument over a very unlikely occurrence.

Jim
Given a 50' and 44', those beams seem fairly representative.

If we want to talk about glancing blows, a container just below the surface, I'll probably slide right over the top. On the other hand a 50' with a full head of steam will still apply a heck of a lot of force to point location on the hull with a glancing blow.

The point is it's a faulty arguement to say the risk is proportional to the beam.
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Old 29-10-2013, 13:49   #105
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Re: 50ft monhull vs 44ft cat

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Well, ignorance is not always bliss! Don't know what draft your friends have, but we are 2.2 metres and have made at least 20 passages through the Sandy Straights. Have personal friends with 2.6 metres who have also made it without issue. It does require watching the tides, but that should not be beyond the skill set of any cruiser.

Cheers,

Jim
Never said they COULDN'T do it, but they WOULDN'T do it. I tried to convince them they'd have no trouble, it's all very well marked, etc, but they just didn't want to take the "risk".
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