speeds

A forum for discussing topics relating to older MacGregor/Venture sailboats.
Interim
First Officer
Posts: 291
Joined: Thu May 08, 2014 7:31 am
Sailboat: MacGregor 26S
Location: Great Plains

speeds

Post by Interim »

I tried out my new sails this weekend, and was a little frustrated I didn't hit the theoretical hull speed (which I think is just under 6.5knts for a 26S). We peaked at 6.1 on a beam reach, with winds 10-12 mph.

Do any of you have a sense if that is "normal" in those winds? Should I be able to get more out of it? Or do I need more pressure to get the big numbers?

--john
paul I
First Officer
Posts: 421
Joined: Tue Jul 19, 2011 5:43 am
Sailboat: MacGregor 26X
Location: Niagara Falls, NY 2000 26X w/Honda BF50 "NoneShallPass"

Re: speeds

Post by paul I »

Low 6's is the best my :macx: has ever done under sail, and its a rare day that it does that.
User avatar
sailboatmike
Admiral
Posts: 1597
Joined: Thu Mar 12, 2015 10:17 pm
Sailboat: MacGregor 26X
Location: Australia

Re: speeds

Post by sailboatmike »

A couple of things here.

1) New sails need to break in, they are pretty much like over starched sheets until they break in, so you cant get the best sail shape.

2) New sails will not make up for other things that are wrong, over weight, incorrect crew positioning, poor foils, increased drag because of build up on the hull, sails not balanced so using to much rudder input and many other things.

In theory the 26X and M should plane under sail (Roger mentioned 17knts for the X) but in reality it will never get there for many reasons but mainly due to weight
User avatar
Freedom77
First Officer
Posts: 481
Joined: Sun Nov 14, 2010 9:43 am
Sailboat: Venture 25
Location: Lake Mead, Nevada '76 V-25 #928

Re: speeds

Post by Freedom77 »

Agree with Paul I and Sailboat Mike. Hull speed is theoretical, like wind tunnel test under ideal conditions. Lots of factors involved. Best we ever did was sailing downwind to Ensenada Mexico with following sea and spinnaker. Hit 8+ knots. WOOO... Fair Winds and Full Sails...Old Salt.
User avatar
Tomfoolery
Admiral
Posts: 6135
Joined: Tue Jul 05, 2011 7:42 am
Sailboat: MacGregor 26X
Location: Rochester, NY '99X BF50 'Tomfoolery'

Re: speeds

Post by Tomfoolery »

Freedom77 wrote:Agree with Paul I and Sailboat Mike. Hull speed is theoretical, like wind tunnel test under ideal conditions.

And even the 1.34 speed to length ratio (S/L)* is just a generic value, and will vary based on the W/L ratio (weight to LWL), and even then it's subject to some uncertainty. But it explains, in part at least, how racing shells can go much faster than their theoretical hull speed would suggest, based on the 1.34 S/L value.

*HS = 1.34 x sqrt(LWL) where 1.34 is the S/L value, which is by no means universal
User avatar
sailboatmike
Admiral
Posts: 1597
Joined: Thu Mar 12, 2015 10:17 pm
Sailboat: MacGregor 26X
Location: Australia

Re: speeds

Post by sailboatmike »

Tomfoolery wrote:
Freedom77 wrote:Agree with Paul I and Sailboat Mike. Hull speed is theoretical, like wind tunnel test under ideal conditions.

And even the 1.34 speed to length ratio (S/L)* is just a generic value, and will vary based on the W/L ratio (weight to LWL), and even then it's subject to some uncertainty. But it explains, in part at least, how racing shells can go much faster than their theoretical hull speed would suggest, based on the 1.34 S/L value.

*HS = 1.34 x sqrt(LWL) where 1.34 is the S/L value, which is by no means universal
Most racing boats are not really true displacement hulls, they are sort of semi displacement hulls, if you look you will see most have a wedge shape, thin at the bow becoming wider all the way back to the transom (I believe its termed as "Fine Entry")

They are also generally have minimal V shape at the rear, the idea being that less boat in the water equals less drag and of course the big one is they are VERY light. On the occasions I race I know I don't have much chance just because I'm over twice as heavy as many of the boats we sail against, some of them weigh in total at not much more than just our water ballast weighs, never mind the actual boat, motor, fuel etc.
Interim
First Officer
Posts: 291
Joined: Thu May 08, 2014 7:31 am
Sailboat: MacGregor 26S
Location: Great Plains

Re: speeds

Post by Interim »

Thanks for the comments, all.

I think what may be frustrating me is that I had an O'Day 16ft that could hit 7.5 when it planed, beating my 26s by more than a knot.

We'll see what stronger wind brings, and probably trying a broad reach. I'm not a racer, but I do take speed as an indication of how well we have the boat set up.

--john
User avatar
sailboatmike
Admiral
Posts: 1597
Joined: Thu Mar 12, 2015 10:17 pm
Sailboat: MacGregor 26X
Location: Australia

Re: speeds

Post by sailboatmike »

Interim wrote: I'm not a racer, but I do take speed as an indication of how well we have the boat set up.
--john
I would take ability to sail to windward as more of a indication of how well the boat is set up. I'm just wondering how you were measuring speed, is that speed over water or speed over ground. I know my boat log reads very low in comparison to my GPS.

As far as I can see the 26S is a true displacement hull and will never plane as such were as the ODay 16 is just a dinghy with sail area that is proportionally much greater(Im presuming the day sailor), it is not hauling around the weight that a 26 does as dinghies don't in general have any or very little ballast.

I have a FJ (flying Dutchman Junior) in my front yard, I would never expect my X to go anywhere near the speed that thing can develop, however the FJ is a very wet ride and if the X had to have the proportional sail area the mast would need to be at least 40 feet high and at least 6 big bloke hiked out to windward
User avatar
dlandersson
Admiral
Posts: 4531
Joined: Fri Aug 27, 2010 10:00 am
Sailboat: MacGregor 26X
Location: Michigan City

Re: speeds

Post by dlandersson »

Mid 5's sailing to windward (60 degrees) is the best I've ever seen. 8)
paul I wrote:Low 6's is the best my :macx: has ever done under sail, and its a rare day that it does that.
Last edited by dlandersson on Thu Jul 26, 2018 2:50 pm, edited 1 time in total.
John McDonough
First Officer
Posts: 421
Joined: Thu May 26, 2005 8:57 am
Location: pittsburgh pa..2000-26X--Honda50

Re: speeds

Post by John McDonough »

paul I wrote:Low 6's is the best my :macx: has ever done under sail, and its a rare day that it does that.

Paul. if that my former 26-x I was I reaching speed of 10.5-11 knot surfing in 3`-4` waves.

That was leaving Erie and heading past long Point Canada on to Port Dover with an empty ballast tank and cruising spinnaker the whole trip.

Myself at the wheel with 2 well conditioned friends as portable ballast.

Even if my speed indicator and GPS was wrong I made it from Erie to Port Dover Canada in less than 5-1/2 hours.

With motor at full throttle in a dead calm I could make the same trip in about 3-1/2 hour.


PS How is that boat holding up. :?: I tried to contact Bud a few times. He might be in bad health. :?:
User avatar
Jonair222
Chief Steward
Posts: 67
Joined: Tue Jun 23, 2015 6:14 pm
Sailboat: Venture 2-22

Re: speeds

Post by Jonair222 »

IF YOU HIT HULL SPEED ON YOUR FIRST DAY I WOULD DRILL A HOLE IN MY BOAT :D
POST AN UPDATE NEXT YEAR LET US KNOW

PS: ANYONE EVER GET THY 22
ON A PLANE ?? :wink:
User avatar
1st Sail
Captain
Posts: 676
Joined: Wed Dec 31, 2008 11:58 am
Sailboat: MacGregor 26M
Location: Moline, IL '06M 50hp Etec
Contact:

Re: speeds

Post by 1st Sail »

6.83knts/7.86mi sog, going upstream against 1-1.3knt current, 70 jib, 3rd reef, beam reach, winds 17-20knts/20-25mph, 1-2ft chop (river sailing).
I'm going over the wall on this one and taking a chance with SailTimer Wind. I just added a new BWYachts full batten main, Jib should arrive soon. Definitely like dropping a V8 in a VW. When it puffs it just takes off with very little additional heel. With the old sails the wind would puff, the boat would lay down, then speed up very little. Once I have the wind data I will report back. Currently all I have is SOG from the chart plotter and the NOAA and USAirNet.com data.
User avatar
Russ
Admiral
Posts: 7543
Joined: Thu Oct 11, 2007 12:01 pm
Sailboat: MacGregor 26M
Location: Bozeman, Montana "Luna Azul" 2008 M 70hp Suzi

Re: speeds

Post by Russ »

I hit 7.1 once downwind. Scared the crap out of me. When I finally came about, wind was howling.

Don't sweat it. It's a sailboat. Enjoy the ride.
User avatar
Freedom77
First Officer
Posts: 481
Joined: Sun Nov 14, 2010 9:43 am
Sailboat: Venture 25
Location: Lake Mead, Nevada '76 V-25 #928

Re: speeds

Post by Freedom77 »

Hi 1st Sail: YEP!! Had 1972 V-222. Planing downwind with spinnaker, following sea and mucho wind. 22 is short and beamy. Friend in other boat took a movie. Long gone. In those conditions you can round up or knock down in a heartbeat. :)
User avatar
Chinook
Admiral
Posts: 1726
Joined: Sun Feb 26, 2006 7:20 pm
Location: LeavenworthWA 2002 26x, Suzuki DF60A

Re: speeds

Post by Chinook »

Our boat is usually very heavily loaded for extended cruising. Best sail we ever had was on the passage from Nassau to the north end of the Exumas, across the Yellow Banks. Wind was about 15 knots on the beam and the seas were moderate, probably 3 feet or less, decently spaced. I started out with full main, and the jib furled just a bit. We were doing a steady 5 knots, with less than 20 degrees of heel. I let the jib out all the way, and the wind may have increased a small bit, with heel right at 20. Consistent speed increased to 6.3, occasionally touching 6.5. We sailed in this fashion for several hours without any adjustment to sails, just steering around the scattered dark patches, which were coral heads probably 10 feet or more below the surface (but you just never know for sure). It was a fantastic passage, and I was almost disappointed when our destination got in the way.
Post Reply