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Old 19-08-2011, 15:54   #1
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The Multihull Trampoline

Does any one know why marine architects designed the cats with trampolines, i just cannot undertand why.
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Old 19-08-2011, 15:57   #2
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Re: A....the multihull trampoline

They want to keep as much weight out of a cat as possible, especially the ends. "Fat" cats are dogs. Cats with weight in the ends hobby-horse.

This is starting to sound like a visit to the farm.

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Old 19-08-2011, 16:08   #3
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Re: The Multihull Trampoline

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Originally Posted by niel12 View Post
Does any one know why marine architects design the cats with trampolines? I cannot understand why.
An open weave tramp does not catch air and drains water quickly.

A tramp a joy to lie upon on a warm evening, the air coming up from underneath.

A tamp can be easier to walk and work on in rough conditions, but this is controversial; I suspect it is a learned skill, but tramps hurt less when you fall and are more comfortable to knee upon.

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Seems like a troll to me. Either way, I had to correct the question.
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Old 19-08-2011, 16:34   #4
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Re: The Multihull Trampoline

The hulls should be much longer than the bridgedeck. Trampolines fill the gap at the bow. The dinghy usually fills the gap aft.
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Old 19-08-2011, 17:06   #5
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Re: The Multihull Trampoline

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A tramp can be easier to walk and work on in rough conditions, but this is controversial; I suspect it is a learned skill, but tramps hurt less when you fall and are more comfortable to knee upon.
I'm not sure its easier to work on in rough conditions, but if you fall it is a softer landing. I went up front on the last charter we did on a Cat during rougher conditions and a wave knocked me down or at least forced me to get down to hang on! Took a few minutes for me to be able to get back up as the waves kept crashing over and keeping me hanging on.

The real downside to being out there in rougher conditions is that there isn't anything to grab on to aside from the tramp itself.
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Old 19-08-2011, 17:39   #6
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Re: The Multihull Trampoline

Tramps are there to evacuate water...as quickly as possible.

The greatest stability risk to a cat is pitchpoling, bow down into waves and water holding the bow down causing the vessel to flip as the waves lift the stern. Tramps are designed to both offer a walkable/enjoyable surface, but most importantly evacuate sea water and allow the bow(s) to rise.

Accordingly, there is also a tradeoff between 'open weave' (typically rope) tramps and the more 'close-mesh' (typically fibreglass) tramps. The open weave tramps are clearly safer (and, in our humble view, preferable) in 'blue water' conditions. The close-mesh tramps, on the other hand, do not evacuate water as quickly, but they are more comfortable to walk and lie on such that they are often preferred for charter vessels where their use will be (often exclusively) on protected waters.
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Old 19-08-2011, 18:02   #7
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Re: The Multihull Trampoline

How far is one able to bounce on the trampolines? What, no springs? What kind of trampolines are those?
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Old 19-08-2011, 18:44   #8
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Re: The Multihull Trampoline

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Originally Posted by maytrix View Post
I'm not sure its easier to work on in rough conditions, but if you fall it is a softer landing. I went up front on the last charter we did on a Cat during rougher conditions and a wave knocked me down or at least forced me to get down to hang on! Took a few minutes for me to be able to get back up as the waves kept crashing over and keeping me hanging on.

The real downside to being out there in rougher conditions is that there isn't anything to grab on to aside from the tramp itself.
A charter... what would you expect.

We run jack lines on the tramp. Very safe and easy, since the tramp is nice and wide at the forestay.
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Old 20-08-2011, 01:49   #9
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Re: The Multihull Trampoline

niel 12, Because of Pitching

In offshore conditions when you might be semi-surfing down waves; your bow can overtake the wave system ahead of you and plunge into the wave. Nets simply let the water through and allow the bows to recover. Solid decking can trip the boat and cause a catastrophic pitch pole--mid-ocean. Netting forward rather than solid decking is crucial for an offshore cat--for comfort and for safety!
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Old 05-09-2011, 08:24   #10
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Re: The Multihull Trampoline

Everything that everyone has said is true about the blue water sailing, just back from one month trip and met people with new 40ft cat with fiberglass tramp, which was simply distroyed in rough seas, it was actually ripped off. This said, could you imagine the power it actually has, and how it can work against you if the bow goes under, byebye and begin a bad dream.
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Old 05-09-2011, 08:53   #11
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Re: The Multihull Trampoline

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Everything that everyone has said is true about the blue water sailing, just back from one month trip and met people with new 40ft cat with fiberglass tramp, which was simply distroyed in rough seas, it was actually ripped off. This said, could you imagine the power it actually has, and how it can work against you if the bow goes under, byebye and begin a bad dream.
Do you know the make of their boat? Where were they sailing it?

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Old 05-09-2011, 09:02   #12
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Re: The Multihull Trampoline

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Originally Posted by raphaella View Post
Everything that everyone has said is true about the blue water sailing, just back from one month trip and met people with new 40ft cat with fiberglass tramp, which was simply distroyed in rough seas, it was actually ripped off. This said, could you imagine the power it actually has, and how it can work against you if the bow goes under, byebye and begin a bad dream.
I believe the make of the yacht is very important, fact is it's the first time i've ever heard of this. The earlier Dean Cats and the Prouts all had a solid glassfibre nose and no netting and no Dean or Prout lost their nose ever!Makes one wonder!
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Old 05-09-2011, 14:14   #13
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Re: The Multihull Trampoline

It was one of the South African boats that Sunsail are using aat this moment, the ones with kind of steps in the front salon window
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Old 05-09-2011, 14:33   #14
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Re: The Multihull Trampoline

Actually the truth of the trampoline is much more simple...It has the benefits as prescribed above but the reason you need/want a trampoline on a catamaran is because of the bow(s) waves. The waves splash through the trampoline..without it you will slam or pound, a most common problem amongst unsuitable designs without a trampoline. Catamarans from Polynesia had longer bows, without the platform or trampoline in place, but modern designs use the tramp to take advantage of the space. A Dean, Gemini and Prout slam like crazy. Tramps come with various size "holes" for offshore or coastal use and are rated by their ability to pass the water.
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Old 05-09-2011, 14:50   #15
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Re: The Multihull Trampoline

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How far is one able to bounce on the trampolines? What, no springs? What kind of trampolines are those?

When we replaced our trampoline last year, I thought about getting actual trampoline material so I could jump on it. then I realized if I did this at sea, I'd need to jump forward so I didn't smash into the boat! Decided that wasn't such a hot idea.



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