Nope you are not lying. Once again this same old tired argument comes up about what some forum, book, sailing magazine, and/or engineer says or reads about sailboat and how it applies to a MAC. I am so tired of explaining this so I am just going to make it simple as I can. It comes down to this are you going to believe what you read or what you see.reastmure wrote:Don't know what they meant by 'the standard calculation' but I get my M up to 6 kts plus under sail given enough wind and the right angle, trimed sails . Was pushing 7 the other day. Unless my new GPS is lying.
Yeah had that you could count on one hand the number of times I have tried to race someone for various reasons but did catch up and almost passed another "real" sailboat down at the Gippsland lakes a few years ago and would have passed him but could see him freaking out at being passed by aWe totally blew past displacement keelboats.
so when he pulled across me just wandered away but point made. 
up to 21 kph whatever that is in knots but did have the motor idling for steerage as it was a pretty hairy narrow passage with plenty of rocks with a good current and only a jib flying in the Cambridge Gulf W.A.
anyway we caught up with him & passed him he was pi$$ to say the least & did all kinda manuvers to try & keep us from passing him 
Five minutes later, the tinnie was off and moving along next to them, and they put up some more sail, I guess it was time to show me my place! Although I am not a racing type, I just couldnt help but unroll the jib. Only problem I could only get it about 80 percent out as there was a bind up there for a few minutes. It didnt matter, because we still pulled away from them. I had 6.3 knots on the GPS and I was towing a fibreglass dingy. It was fun blowing them a kiss as I pulled away Got some video too Boblee wrote:Yeah had that you could count on one hand the number of times I have tried to race someone for various reasons but did catch up and almost passed another "real" sailboat down at the Gippsland lakes a few years ago and would have passed him but could see him freaking out at being passed by aWe totally blew past displacement keelboats.
Had the
Lieu Daze wrote:Seen many posts on the subject but short form of what I understand....
True displacement hulls, full keel standard sloop, have a terminal hull speed of 1.34 times the square root of the length of the waterline. If your Mac had a displacement hull it's terminal hull speed would be 1.34 x sq rt (23.16) = 6.45 knots.
The terminal hull speed of a displacement hull is exactly that...terminal, meaning even if you put a jet engine on the back it just builds a bigger pressure wave up front and still only does say 6.96 for a 27 footer, (at WL).
Because you can get your Mac up past what would be it's terminal hull speed easily with the motor means your riding a semi-displacement hull. So if your riding light, (with full ballast for at least your own souls sake please), reefed on a beam, your pals hiking' out with their wives on their shoulders, you can expect to pass many low 30' ers at approaching 8 knots or a touch above with with only the drag of your smile holding you back.
Best speed on mine was just after purchase, (super light not even a drink holder on yet), without much of a clue how to properly trim, and we hit just over 7.5. It won't be that light again so happy when we get a 7 out of it.
Your video is showing MPH. 7.5 MPH, which is 6.5 knots, which is the theoretical hull speed for a MacGregor. That said, unlike a normal displacement hull, it is possible for MacGregors to get up on a plane, even slightly, under sail and perform better than maximum theoretical hull speed in downwind conditions.ROAD Soldier wrote:Nope you are not lying. Once again this same old tired argument comes up about what some forum, book, sailing magazine, and/or engineer says or reads about sailboat and how it applies to a MAC. I am so tired of explaining this so I am just going to make it simple as I can. It comes down to this are you going to believe what you read or what you see.reastmure wrote:Don't know what they meant by 'the standard calculation' but I get my M up to 6 kts plus under sail given enough wind and the right angle, trimed sails . Was pushing 7 the other day. Unless my new GPS is lying.
http://www.youtube.com/watch?v=hQaq0c6Bvoc
Not even close to being my fastest day but is one I have on video
Obviously you didn't see the whole video I was hitting 8.1 MPH and also wrote that is not my fastest speed either, not even close to be exact. Also one more thing that I didn't mention is that the lower Potomac is a tidal river and guess what direction it was going in that video? If you said with me you would be 100% wrongmastreb wrote:Your video is showing MPH. 7.5 MPH, which is 6.5 knots, which is the theoretical hull speed for a MacGregor. That said, unlike a normal displacement hull, it is possible for MacGregors to get up on a plane, even slightly, under sail and perform better than maximum theoretical hull speed in downwind conditions.
. Sweet! I've seen video up to 10.9 knots on a Mac, so clearly planing is going on. You were going downwind, correct?ROAD Soldier wrote:Obviously you didn't see the whole video I was hitting 8.1 MPH and also wrote that is not my fastest speed either, not even close to be exact. Also one more thing that I didn't mention is that the lower Potomac is a tidal river and guess what direction it was going in that video? If you said with me you would be 100% wrongmastreb wrote:Your video is showing MPH. 7.5 MPH, which is 6.5 knots, which is the theoretical hull speed for a MacGregor. That said, unlike a normal displacement hull, it is possible for MacGregors to get up on a plane, even slightly, under sail and perform better than maximum theoretical hull speed in downwind conditions.
