How fast ?

[curtis from carlsbad]

How fast do old macs/ventures sail? (MPH) Please compare to 26x/26m.

[Sumner]

How fast do old macs/ventures sail? (MPH) Please compare to 26x/26m.

This might help or not.

The following pages list low, high and average performance handicaps
reported by USPHRF Fleets for over 4100 boat classes/types. Using Adobe
Acrobat’s ‘FIND” feature, <CTRL-F>, information can be displayed for each
boat class upon request. Class names conform to USPHRF designations. The
source information for this listing also provides data for the annual PHRF
HANDICAPS listings (The Red, White, & Blue Book) published by the UNITED
STATES SAILING ASSOCIAION. This publication also lists handicaps by
Class/Type, Fleet, Confidence Codes, and other useful information.
Precautions: Handicap data represents base handicaps. Some reported
handicaps represent determinations based upon statute rather than nautical
miles. Some of the reported handicaps are based upon only one
handicapped boat. The listing covers reports from affiliated fleets to USPHRF
for the period March 1995 to March 2007.

HIGH, LOW, AND AVERAGE PERFORMANCE HANDICAPS ORGANIZED BY CLASS/TYPE

Boat--------------------Lowest ------------Highest-------------Average

MACGREGOR 26 X -----216--------------- 273------------------- 228
MACGREGOR 26 DB--- 210---------------- 219------------------ 213
MACGREGOR 26 S ---- 210---------------- 258------------------ 222

The X has the largest difference between the lowest and the highest. It has seemed like I've seen other PHRF's for the X and M over 300. This list didn't show the M. The 26 D was also lower than any of the smaller/shorter Macs or Ventures. Now the Mac 65 is in a class all by itself.

The above won't give you speeds, but will tell you how much faster one boat is suppose to cover a mile vs. another if I understand PHRF correctly. I think I've seen hull speeds for the S and D at a little under 7 knots, but that might not be right.

c ya,

Sum

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[madguy]

I dont quite understand hull speeds etc, however i regulary see 7 knots on my 26S in only 17-20 knot wind and have seen on occasions 11 knots..noy many people beleive me but i think my gps is quite accurate.

Also i have raced my mate who has a 26X 2002 and he cant keep up with me..

Dont know if thats of any use??

Madguy

[Currie]

FWIW -

Hull speed just has to do with the natural speed that waves travel through water. It's a limiting factor that applies to heavy displacement boats, somewhat to lighter disaplacement boats (26D/S), to a much lesser degree for semi-planing boats(M/X), and not much at all to planing boats.

The faster a boat goes, the taller the wave that builds up in front of the boat. Behind that wave a trough forms - further behind, another crest forms. At slower speeds, you can usaully see a couple of crests - one at the bow and one partway back along hull sides. As the boat picks up speed, the second crest moves back all the way to the stern. At this point there's a bow wave, a stern wave, and a big trough in between. The boat is literally sitting in a "hole" - moving along at the natural speed of waves in the water. From here on, going faster means climbing out of that hole (termed "shooting the hole"). It takes a quantum leap in power to do that - no matter what the kind of boat. Heavy displacements don't have a chance. Displacement hulls in general have a rounded transom that is now stuck to the stern-wave like a suction-cup. Lighter displacements can sometimes pull it off on a run in brisk winds, because they don't have as much wetted surface. Semi's and planing hulls have a flatter hull bottom to ride up over the bow-wave and a squared-off transom that "shears off" and releases the water from the stern - this frees the boat from rearward suction. The power needed to shoot-the-hole is now much less than with the displacement-hulls.

Here's a displacement sitting in a hole: (random pic from the internet)...



You can actually use this picture to estimate the speed of the boat (if you know the hull length of the boat).

...and Mike Inmon sailing an M at about 80% of what would be hull-speed if the we're a full displacement hull...



~Bob

[argonaut]

Curtis,
I believe you are trying to compare the speed capability of older boats to newer boats.
So, maybe mac Ventures to M or X model boats.
Currie´s elegant explanation wonderfully illustrates the concept of ¨hull speed¨ and that applies to any boat with a curved bottom, the more curved, the more it applies.
Age isn´t in the equation.
So a 30 year old 25 foot boat should be capable of about the same ´hull speed´ as a 26 foot 2010 model, comparably rigged.

Speedwise the difference would be negligable.

Sailing performance is more than speed though. It includes the ability to sail upwind and downwind, and the newer models do not sail upwind as admirably as the older ones such as Ventures and the speed demon 26C and 26D models. The newer boats compromised some sailing ability to be able to motor at high speed.
So it depends what you like to do.

The PHRF numbers give an idea of seconds over mile, so subtract my X having a 273 from my pal´s 26D having 214 and he should sail past a given mark about 61 seconds before me.

[JoeVacs]

I dont quite understand hull speeds etc, however i regulary see 7 knots on my 26S in only 17-20 knot wind and have seen on occasions 11 knots..noy many people beleive me but i think my gps is quite accurate.

Also i have raced my mate who has a 26X 2002 and he cant keep up with me..

Dont know if thats of any use??

Madguy

Your GPS speed is how fast you're moving across the globe, not how fast you're moving in the water. If your hull speed is 6knots you aren't going to go any faster than that. If the current or water speed is running at 5 knots and your in the stream, you could in theory be going 12 knots on your GPS, but your actual speed through the water is still only hull speed. Here's a hull speed calculator
http://www.sailingusa.info/cal__hull_speed.htm

Also Knots and miles per hour are not the same, and all the GPS I've seen show mph not knots. http://www.grc.nasa.gov/WWW/K-12/WindTu ... s_mph.html

[c130king]

I don't think we are limited to theoretical hull speed...our hulls are not theoretical. I mean they have some planing capability and they are pretty light. I am sure I have been over hull speed without too much current.

Jim

[JoeVacs]

I was thinking that all the new Macgregors with the big 50hp outboards were plaining hulls , maybe not....

[madguy]

I dont quite understand hull speeds etc, however i regulary see 7 knots on my 26S in only 17-20 knot wind and have seen on occasions 11 knots..noy many people beleive me but i think my gps is quite accurate.

Also i have raced my mate who has a 26X 2002 and he cant keep up with me..

Dont know if thats of any use??

Madguy

Your GPS speed is how fast you're moving across the globe, not how fast you're moving in the water. If your hull speed is 6knots you aren't going to go any faster than that. If the current or water speed is running at 5 knots and your in the stream, you could in theory be going 12 knots on your GPS, but your actual speed through the water is still only hull speed. Here's a hull speed calculator
http://www.sailingusa.info/cal__hull_speed.htm

Also Knots and miles per hour are not the same, and all the GPS I've seen show mph not knots. http://www.grc.nasa.gov/WWW/K-12/WindTu ... s_mph.html

Ive managed to figure out what the actual speed is taking into consideration the speed of current etc,,however. i sail on an inland man made lake.. taking this into consideration and the fact that there is no current are you then saying that my gps is incorrect in telling me that i am travelling at 11 knots when there is no current to consider. and if my hull speed is only 6 knots i therfor cannot sail at anything more than 6 knots under any curcumstances??...

My gps is the standard horizon cp180i which gives the speed ov the vessel in knots as far as im aware!!

Just want to clarify??

Maadguy

[bubba]

Last spring we were sailing up stream on the Columbia river in a big gorge at the big bend of the river where there was a 2 mph current and we were on our 3rd reef only, on a droad reach surfing 4 to 5 ft wind waves in 35 gusting to 45+ mph breezes and our best speed was 9.5 gps mph surfing down the wave and averageing 7.5 gps mph up the next wave. We did a bit of WALLOWING quortering off the waves but my wife got used to the boat's movement and lightened up on the wheel as she was skippering that day. The choise of 3 reefs lets us play it safe when the wind waves get big. Were not really worried about wind speed or boat speed, just crusing safely any time any where.

[Sumner]

............are you then saying that my gps is incorrect in telling me that i am travelling at 11 knots when there is no current to consider. and if my hull speed is only 6 knots i therefore cannot sail at anything more than 6 knots under any circumstances.....Maadguy

Are you seeing 11 Knots sustained over say at least 10-15 seconds or is that the high knots when viewing the "trip computer" results?

Our 76 will see unrealistic high numbers on the "trip computer". The average speeds will be correct. I've noticed while walking around town with ours that just stepping down off of a curb for a second the speed will go from 3 mph to over 4 mph and then go back to the 3. Also since the GPS is not accurate to a foot or less it can think you are maybe 8-9 feet behind where you currently are and then the next second think you are 8-9 feet ahead of your location. I don't know how it handles that, I guess by doing a lot of averages, but I could also see where that could give some false speeds.

If you are seeing the reading for 10 seconds or so steady then I would say it is accurate and you have a fast boat and should think about entering some races . I also can't believe how fast 5-6 knots can seem at times, especially after we have been floating in the same spot for a couple hours waiting for some wind.

c ya,

Sum

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[c130king]

I also can't believe how fast 5-6 knots can seem at times, especially after we have been floating in the same spot for a couple hours waiting for some wind.

Ain't that the truth. And 5-6 knots seems like you are screaming when close-hauled when comparing 5-6 knots on a run.

But I have seen over 7+ knots for 20-30 seconds several times...gusts kicking up the speed and I guess the boat is starting to climb out of its hole. That is why I think hull speed is only theoretical in our case...our hulls are not exactly traditional.

Jim

[DaveB]

S or D Mac. will tell you...me not know, me not tell, raise sail,sail like Xell.
D's and S's hull speed is around 6.2 mph but they well exceed that often.
In 15 knots of wind on a broad reach can exceed 6.8mph and can do 7.2mph or more surfing.
My X can also do that...just takes more wind to push the beast.
Friend of mine has a Mac.S and can do circles around me in winds 5-8mph.
Gps over ground is only thing that counts as thats what you look for if you want to get someplace. If you are just sailing with no destination a 2 knot current sailing against and beating to windward is just fun tho you don't cover ground half as fast.
Thats why they call it beating to Windward, Ya gots to suffer.
Dave

How fast do old macs/ventures sail? (MPH) Please compare to 26x/26m.

[Sumner]

D's and S's hull speed is around 6.2 mph but they well exceed that often.
In 15 knots of wind on a broad reach can exceed 6.8mph and can do 7.2mph or more surfing....

Dave do you mean knots? I've seen 6.5-6.8 knots quoted different places for the hull speed on S and D's. That would be 7.48 mph to 7.83 mph.

While that S is running circles around you, you are probably down below standing up walking around making lunch, while is is all hunkered over down there trying to put a peanut and jelly sandwich together ,

Sum and Ruth (owners of a spacious (not) S)

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[Nautek]

Hi Maddguy

Even enclosed lakes have currents
You may not realise but if there is any sort of wind blowing on a lake then there will be a current.
How that flows will be dependant on bottom profile of the lake

Allan