G'day,

Has anyone any experience of using net instead of trampolines on a beach cat? Or know why big boats use net and little ones cloth? Seems it would be less windage when flying a hull, although maybe more drag when sailing flat?

any input appreciated.

regards,

Rob

A couple of possible reasons...

Harder to keep the ropes under control on a beach cat with nets rather than tramps. They keep slipping through the holes, dragging in the water and being annoying to use. The bigger boats can keep most of their ropes on the hulls. I have centreline lacing at the moment on my beach cat and it will be changed to a proper tramp soon, mainsheet keeps getting sucked through and causing dramas.

Windage in relation to capsizing would be significant on the big boats, particularly in the predominantly offshore racing they do, if they had tramps rather than nets. Not so important for off-the-beach cats racing inshore.

Another one may be that a beach cat you may be wiring and so you need a surface that can handle "sidways" movement as well as up and down. I can see all sorts of damage from trying to slide across netting.

Nets will tear up your bare knees. Bigger the cat, the easier it is to stay off of your knees.

Kris
F-16

Many one design cats have a rule that precludes you from using any non-woven material for the tramp. For example, the story I heard was, it's banned on the Tornado because no one wanted to use it but it it can be an advantage under some conditions.

If you want a sort of net, there is a knitted dacron fabric (http://www.sailrite.com/Categories/Trampoline-Mesh_2).It's soft, net like and works well. HOWEVER, it's very UV sensitive. Even protected from the sun it may only last 2 years. There is also a perforated vinyl (like a solid Hobie tramp with lots and lots of holes in it) but I have not seen that material in years

Everytime I buy or build a trampoline, I look around, think about it, and decide to use some form of polypro mesh. It's light, durable, and strong. Now if someone makes that knitted fabric out of polypro, I might, reconsider

If it wasn't for OD rules, all beach cats would use nets.

Take a look here for knotless dyneema nets that need no reinforcement in the edges and are the lighter, stronger and simpler thing you will find.

There's nothing holding back the a-cats and they're still using poly-pro.

Are you sure?

I for one would not think that you would be able to slide along the tramp like I can on my currnet one when tacking.

There are MANY cat sailors who dont race, nor care about OD rules that dont use nets (ME)

I stand corrected. People have different preferences. I think nets are preferable because they are lighter, drain faster and reduce windage, thus making the boat safer, But that's just me.

aside from sunrise (multihullnets.com) anyone know where to find this netting or something similar? Holes need to be 3/8inch or so

This seems to be (blue) coated knotless polyester, almost the same as the dyneema version. I believe you can find it in the same place, Net Systems, Seattle.

We use some of that on our machinery we build...that weave and pattern in polyester is equivalent to 20 grit sandpaper. It's VERY rough. It's also very "springy" and would be difficult to get it reasonably tight for a trampoline application.

I don't think nets would reduce windage while sailing, ie. at high speeds with wind flow along the length of the net. They would be less windage at low wind speeds with the wind going through the net, ie. when capsizing.

It is for the 31 and I don't keep them very tight- you have to loosen them to fold the boat up anyway then re-tighten them. kind of painful if you do it with any sort or regularity.
looking for winter projects...

Sailrite carries something similar.

http://www.sailrite.com/Categories/mesh-for-trampolines

I have that stuff fwd of the main beam on Flight Risk, it allow me to be up there, but even tensioned very tightly it'll sag a good 12" when I'm on it(I'm 160 lbs). And it is abrasive, and uncomfortable to lie on. It's hard to imagine liking it as a trampoline.

Dave

Boyer A
Javelin
FR 24' cat

Exactly. Windage isn't helpful when the boat heels.

Ian Farrier recommends wider net openings. He is concerned with the boat taking off in a storm, even if grounded.