The full rig was intended to get good speed in low wind conditions. Racing boats are typically overpowered upwind in around 12kts of wind. I never played around very much with the sail area to find that which maximised windward performance in different wind strengths. I recall that with full sail area it went faster upwind with three crew members than with two. But it was faster with less sail area.
I did look at pitching, which gives further insight into performance considerations in higher wind strength. In wind above 20kts, operating in fully developed waves offshore, there is propensity to nose dive and not recover when sailing with full sail area; meaning pitchpole is a possibility. Having the ability to move crew to the aft end of the ww hull would counter that a little.
A 40ft boat is going to suffer performance losses upwind in waves for any wind above 15kts in open water. Adding weight to enable carrying full sail to higher wind strength upwind is not going to offer much advantage. It may make pitching worse and be a disadvantage. It will stress components more.
If the boat is light then the flat bottom is reasonable for planing. The polars do not consider any benefit from planing. The lee hull on BL would reduce drag by up to 15% if it was trimmed to get the nose up to generate hydrodynamic lift. Lightweight cats with flat bottoms will sail with the foot of the stem out of the water when trimmed nose up in the first place. I think Rob observed the foot of the stem above water level the brief sailing he did on BL but that was with only a 6m high rig so pitching moment very low. Adding weight in the middle of the ww hull is not going to assist planing. Shuffling ballast to the trailing end each shunt could be beneficial if there were no crew ballast to easily shift about.
Rick
On 28 Mar 2019, at 9:43 pm, '.' eruttan@yahoo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:Rick, Bjorn;
If one was gonna race, or even fast play, a Bucketlist, would not it be easy to have added a simple water ballast to be able to put more weight to ww, as needed, to push the boat?
It seems to me to derate the boat when there are simple easy well known ways to help it reach more of it's potential is inaccurate, or unfair.
Am I wrong? Is it not like talking about the performance of a cat without a jib? Because you cannot know what jib a person would use?
__._,_.___
Posted by: Rick Willoughby <rickwill@bigpond.net.au>
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a new topic | • | Messages in this topic (12) |
SPONSORED LINKS
.