boat fish tails

[NovaSS]

This isn't for a vdrive boat. I know a guy with a barrel back style mahogany runabout and he says at high speeds the boat fishtails at the transom. What causes this type of motion and what can be done to stop it minimize it. Thanks for the help.:)

[RiverRacer]

Loose rudder maybe???..:confused:

[AquaCraft]

Have your buddy make sure his rudder is deep enough to stay in the water at high speed. If the rudder is "short" he can end up walking the rear of the boat sideways when he comes down prop first at speed. If you like being dry you want the rudder to land first. 'Can't imagine an old barrel back going that fast or that loose though... I like the loose rudder or steering hardware idea better.

[Norcal_73]

or the rudder cables, tensioner pulleys maybe?

[NovaSS]

thanks guys for the ideas. Ya I cannot imagine his boat going that fast but that is what he says. I'm mention these posibilites to him:)

[shooter2]

I drove and old Mandella when I was young. The rudder in it came out of a cabin cruiser I think. It was huge and made the boat dart. Doubt that the problem here though. But what style of rudder does it have?

Brian