Topics

Roll Chocks Bilge Keels

Richard A. Miller
 

I misstated when I said,

“Bilge keels . . . might have been oriented vertically.” More likely, perpendicular to the plane of the bottom at point of attachment.

Richard Miller

.

On Apr 14, 2020, at 11:43 AM, Richard A. Miller <ramillerco@...> wrote:


Dan Pease wrote:

“how does one know the flow of water around the hull with out extensive testing. . . getting the keels aligned a little bit wrong could affect the behaviour of the boat and [boost] fuel consumption.”

Absolutely right, Dan. The water-flow characteristics over the Willard hull are what make it so efficient. On the other hand, the magnitude of any effects would be minimized by the low, full displacement speed at which the boat moves - quite different from a “fast trawler” that exceeds hull speed. But note that the fuel consumption curve goes up exponentially above 5 or 6 knots, so whatever effects were encountered would be magnified at normal cruising speeds (which I consider to be 7 knots or so over long distances, except during severe conditions on the nose).

Richard Miller
W40 FBS Adria , currently for sale 😢

Pease, Dan
 

Richard,. I could take credit for that quote, but I don't think it was me. 

I do agree, although I think the new additions would have to be put on very wrongly and it might be obvious. But everyone has a different eye.
In a way, having the keels misaligned to a certain extent may enhance their effect while underway.  I'm thinking if they form a very slight funnel effect.
Pardon my probable misuse of effect with regard to affect.

Dan

On Tue, Apr 14, 2020, 13:09 Richard A. Miller <ramillerco@...> wrote:
I misstated when I said,

“Bilge keels . . .  might have been oriented vertically.”  More likely, perpendicular to the plane of the bottom at point of attachment.

Richard Miller

.

On Apr 14, 2020, at 11:43 AM, Richard A. Miller <ramillerco@...> wrote:


Dan Pease wrote:

“how does one know the flow of water around the hull with out extensive testing. . .         getting the keels aligned a little bit wrong could affect the behaviour of the boat and [boost] fuel consumption.”

Absolutely right, Dan.  The water-flow characteristics over the Willard hull are what make it so efficient.  On the other hand, the magnitude of any effects would be minimized by the low, full displacement speed at which the boat moves - quite different from a “fast trawler” that exceeds hull speed.  But note that the fuel consumption curve goes up exponentially above 5 or 6 knots, so whatever effects were encountered would be magnified at normal cruising speeds (which I consider to be 7 knots or so over long distances, except during severe conditions on the nose).

Richard Miller
W40 FBS Adria , currently for sale 😢