Tube stress!

[dangers]

Should the tubes be clear of the water when the boat is at planing speed? The tubes on my boat drag, and obviously wobble like mad at speed. I am concerned that this might put undue stress on them, and also can't do much for efficiency both in terms of fuel economy and speed. Should I be concerned? Are my tubes normal?

[slimtim]

A quick answer for you...

depends on your boat
Some have high tubes that clear the water at speed (only coming into effect when cornering) which mean higher speeds but less stability.

Some have lower tubes for more stability at rest and at speed. The extra drag reduces top end speed a bit though.

The tube will wobble around like jelly but I think this helps to absorb some of the shock of a heavy sea.

Hope that helps

Tim

[TIM]

I think that tubes should be run farily hard......

Because as the tubes vibrate... they are moving around , and they could be chafing against the fiberglass mounting coller, this over a long period of time could wear a hole in a tube , in a place which is a pain in the arse to repaire....

Just a thought ?

[dodl]

Hello,

Yes, many boats handle this different. Some are designed to get out completely. Mine for example has a pretty high deadrise and comes out of the water completely. Some others i saw, always have some Tubes in the water, and go pretty fast though.

The drawback with the Tubes out of the water is the stability at higher speeds. When i go around 27knots, my boat "whips" a bit, when i do some slight turns, while the other desingns are lying rock solid in the water.
On the other side, i always stay dry in my boat, where the others get some spray inside.

To be honest, in my region the vast majority of RIB's always have the Tubes in the water at the Transom and some way forward. My Avon is quite exotic here. All the "italian style" RIB's have a much lower deadrise an the Tubes down...

cu
martin

[Nick Hearne]

Sounds like you may want to put some more air in your tubes!