Tumblehome in Performance Dinghy Hull Design

[Doug Lord]

Does anybody have any thoughts on tumblehome in performance dinghy design? I found an example here: New Rules IC

[wet feet]

The canoe is a little removed from the typical performance dinghy in that it uses the plank to generate righting moment and the loss of beam at deck level makes no change to this aspect of the boat.In addition,the self draining nature of the boat makes the shipping of water less of an issue.The slight saving of weight resulting from the reduction in total surface area of the hull and deck probably justifies the approach.

[ancient kayaker]

Originally Posted by Doug Lord

Does anybody have any thoughts on tumblehome in performance dinghy design? I found an example here: New Rules IC

Don't see the point unless you are a fisherman. Tumblehome is fairly common in canoes for easier paddling, but it would seem counterproductive in a rowboat unless it had outriggers and in a sailboat it would make hiking more difficult. In a motorboat it would likely make it a wetter ride and I suspect it is mainly done for style.

[bistros]

Originally Posted by ancient kayaker

Don't see the point unless you are a fisherman. Tumblehome is fairly common in canoes for easier paddling, but it would seem counterproductive in a rowboat unless it had outriggers and in a sailboat it would make hiking more difficult. In a motorboat it would likely make it a wetter ride and I suspect it is mainly done for style.

Steve designed in tumblehome on Wonk to aid quick draining of the deck, as it was a wave piercing design that goes through wave and chop instead of over it. The IC doesn't ever have anyone hiking (it has a sliding seat).

Performance planing boats generally go in exactly the opposite direction to tumblehome, with wide flaring sides allowing a narrow beam at waterline and a wider hiking/trapezing platform at deck height. Canoes are a different breed entirely.

[ancient kayaker]

Originally Posted by bistros

Steve designed in tumblehome on Wonk to aid quick draining of the deck, as it was a wave piercing design that goes through wave and chop instead of over it. ...

Submarines are different too!

[gonzo]

Don't say concrete

[ancient kayaker]

I won't! I promise!

[CTMD]

IIRC the IC rules don't allow flare. Adding some tumble home will help stiffen the panels without increasing the weight.

[gggGuest]

Originally Posted by CTMD

IIRC the IC rules don't allow flare.

They do, although there are limitations. But there's limited value in having flare.