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Re: 26m sailing performance

Posted: Fri Jun 07, 2013 5:39 am
by dlandersson
Or, 26M's attract really bad sailors. :(

I blame it on the blue paint, myself. :P
mung wrote:Perhaps the Macgreggors slow reputation is based on its poor windward performance which is compensated for on other points of sail.

Regards Mung

Re: 26m sailing performance

Posted: Fri Jun 07, 2013 5:52 am
by Obelix
mung,
I believe the Macgregor 26 in your table is neither the :macx: or the :macm: , but the older Mac 26 a pure sailboat :(

Obelix

Re: 26m sailing performance

Posted: Fri Jun 07, 2013 6:33 am
by BOAT
Not bad for a boat with this much accomadation and a lot of windage
It's SO weird because I remember when Roger first came out with his boats (Venture 22 and stuff) the accommodations were horrible compared to other trailer boats. Now Rogers boat has more accommodation that ANY trailer boat!

Re: 26m sailing performance

Posted: Mon Jun 10, 2013 11:54 pm
by Roymac
Thanks for all the reading. All the photos I have seen from members activities, I have noticed that the forstays are always slack.
If you can tighten them and use the jib the Mac26M will point just high as 8M Benitou. Not sure of the spelling but I have had to raced with these boat because the other MacGregors would not come out to play. I have had a smile on my face when I have been upwind and ahead of these boats.
I have removed the two copper washers and stood my mast on a bearing. My rigging tension is such that the mast just rotates by its self and just before the spreaders distort.
Hope this info helps. I don't use a gauge.
I'm considering changing my out board to the new 9.9 Honda. Reducing weight changes the boat dramatically. Although I must say I only sail in light winds. 15knots max.
Lone Mac Racer

Re: 26m sailing performance

Posted: Mon Sep 16, 2013 9:40 am
by rpaulwmson
When I berthed my 26X in the San Francisco Bay Area near Coyote Point (i.e., "Hurricane Alley"), we had beer can races once a week in the late afternoon when winds were usually 25-30 knots. There were typically 8 to 10 boats of different types and sizes from 22 to 32 ft (Catalina, Ericson, Santana, etc), none were racers but the skippers did race them consistently. I learned quickly that the Mac26X was at a serious disadvantage upwind, even when carrying a 100% jib instead of a partially furled Genoa, and it could only point 45 - 40 degrees true wind at best, in rough water with high winds. The boat was simply overpowered and being light, could not cut through the chop and tended to squat.It was also very sensitive to the optimum angle when close-hauled, even a couple degrees off would either stall it (too close) or overpower it (it is very tender close-hauled in these conditions). The centerboard/water ballast was no match for an iron keel and a heavier, stiffer, lower profile boat (like an Ericson). On the other hand the Mac26X behaved fairly well on a broad reach and quite well on a downwind run, since it is light and lack of an iron keel does not hurt - it behaved almost like a dinghy, even in rough water. In fact I could make up time on the heavier, stiffer boats downwind. Overall, however, we generally came in last in these beer can races and the Mac26X cannot compete with iron keel boats (or even come close) in high wind conditions.

Re: 26m sailing performance

Posted: Mon Sep 16, 2013 3:00 pm
by Ixneigh
Stick to races that include a stretch of 2 feet deep water...That's how I win races! :D :D :D :D :D
Ix

Re: 26m sailing performance

Posted: Mon Sep 16, 2013 4:35 pm
by mastreb
drams_1999 wrote:This means I can sail 105/2 = 52.5 degrees from directly in the eye of the wind.
This is very close to right for the conditions you describe. The Mac's easy upwind performance is about 50 degrees, as measured by my anemometer and chartplotter data.

You can get better upwind performance by:

(a) Use a jib. This is worth about 7 degrees upwind. Sans jib, you can furl your genoa to 100% and move the sheets to the cabin-top to get better upwind performance.

(b) move faster :-) --the closer you are to 6 knots, the easier it is to point upwind. This is because you get much better lift on the daggerboard.

(c) Keep heel to 15 degrees. Beyond 20 degrees the boat slows dramatically. Use your mainsheet constantly to keep heel right at 15..20 degrees.

(d) Keep a tight helm (or use an autopilot to keep heading). The Mac helm wanders more than most boats, especially if you leave the outboard connected. Even the slight "S" curve this creates robs you dramatically of upwind performance because you move into and out of irons constantly.

Some claim the ability to get down to 30 degrees of irons using a true jib and an autohelm. It should be easy to get to 40 degrees with these recommendations, and if you don't post back here so we can figure out why.

Also keep in mind that you will probably make better VMG at 45 degrees than 30 even if you can do 30, because the boat slows. The difference between 4 knots at 30 degrees and 6 knots at 45 degrees can easily make up for a tack.

Matt

Re: 26m sailing performance

Posted: Mon Sep 16, 2013 5:48 pm
by Catigale
Some claim the ability to get down to 30 degrees of irons using a true jib and an autohelm.
They can claim the boat might point to 30 degrees but the course will not be 30 degrees to true wind. I have yet to see a GPS track showing 80 degrees of course track angle posted.

Re: 26m sailing performance

Posted: Mon Sep 16, 2013 11:02 pm
by mastreb
I'm going to Catalina on the 4th of October from San Diego, and will spend four days beating into the wind. I've got an anemometer, chartplotter, and will have an auto helm on by then, along with new sails and a rig retention. I'm not the world's best sailor and I don't expect much from the wind but I will be beating into it for three or four days.

My goal is to try to derive a reasonable and instrumented set of polars for the 26M with as little human factor involved as possible.

I'll post what I'm able to do.

Re: 26m sailing performance

Posted: Tue Sep 17, 2013 4:09 am
by March
Lookin' forward to it, Mastreb. Fair winds and easy seas

Re: 26m sailing performance

Posted: Tue Sep 17, 2013 10:12 am
by dlandersson
I may be missing something. My favorite angles are 60 degrees port or starboard beating into the wind. Doesn't seem as much fun (or as fast) with the wind behind me. :?
mastreb wrote:I'm going to Catalina on the 4th of October from San Diego, and will spend four days beating into the wind. I've got an anemometer, chartplotter, and will have an auto helm on by then, along with new sails and a rig retention. I'm not the world's best sailor and I don't expect much from the wind but I will be beating into it for three or four days.

My goal is to try to derive a reasonable and instrumented set of polars for the 26M with as little human factor involved as possible.

I'll post what I'm able to do.

Re: 26m sailing performance

Posted: Tue Sep 17, 2013 10:44 am
by mastreb
dlandersson wrote:I may be missing something. My favorite angles are 60 degrees port or starboard beating into the wind. Doesn't seem as much fun (or as fast) with the wind behind me. :?
You definitely feel like you're going faster with the wind in your face when beating, no doubt about it. That's because you've got 12 knots of wind and 6 knots of boat speed summing to the sin(60) of 18 knots.

Down wind you've got 12 knots minus 6 knots summing to 6 knots-- much less exciting and hotter. But the speed is actually better.

Matt

Re: 26m sailing performance

Posted: Fri Sep 20, 2013 7:02 am
by grady
mastreb wrote:But the speed is actually better.

Matt
Actually in your description the boat is going the same speed up and down wind. :D

Re: 26m sailing performance

Posted: Fri Sep 20, 2013 7:22 am
by RobertB
There is one opinion that I recently heard and I think may be true: when running with the wind, the apparent wind on your sail is the real wind minus the speed of the boat - kind of self limiting. When reaching, the faster you go, the faster the wind on the sails.

Re: 26m sailing performance

Posted: Fri Sep 20, 2013 8:48 am
by mastreb
RobertB wrote:There is one opinion that I recently heard and I think may be true: when running with the wind, the apparent wind on your sail is the real wind minus the speed of the boat - kind of self limiting. When reaching, the faster you go, the faster the wind on the sails.
Yep, that's correct and it's the magic of apparent wind.

There are two force vectors going on when you're pointing:

1) The aerodynamic lift vector coming from the higher speed apparent wind which adds to speed.

2) The drag vector coming from windage which subtracts from speed.

The lift vector increases as you rotate from 90 to ~10 degrees (below 10 its not possible to keep an aerodynamic sail shape), but the drag vector increases faster, and eventually overwhelms the lift vector. As soon as the drag vector has the same magnitude as the lift vector, you are in irons. A really good sloop might get down to 15 degrees. I've never done better than 40 in my Mac.

Where that crossover point occurs varies by boat but it's increased by windage. The Mac's relatively high windage increases the power of the drag vector, and the low weight makes it susceptible to immediate losses when you're on the edge of that crossover. A heavier boat will slow down near irons, whereas Macs pretty much stop immediately like a hove-to. This factor tends to keep Mac sailors from pushing it, and staying around that 60 degree mark where the boat has its maximum lift to drag force.

Once you rotate behind 90 degrees, the drag vector and lift vector sum; however the lift vector goes rapidly to zero by the time you're on a broad reach, while the drag vector goes to maximum (which is never higher than true wind).

The real beauty of the fore-aft Bermuda sail plan is that it converts smoothly from lift mode to drag mode as you rotate from pointing to downwind.