MacGregorSailors.com

Per some of the questions on 'why modify the centerboard'.

#1 The stock board will not handle a heavy sea state. By that I mean contineous sailing (not motoring) in seas over 8 ft. & winds above 20 knots (usual heavy trade days down south).

#2 On the question of how well the 'wing' works. Honestly, it does not seem to make any difference one way or the other, except that it offers less resistance for the weight of ballast I needed to keep the board down. One drawback I'm hoping to correct by glassing the wing is the fact that it can sometimes catch weeds & kelp where the fins meet the board.

#3 After all is said and done, we all know the 26X points to windward about the same as the Penta, Nina, & Santa Maria did (i.e. pointing might look good but the boat 'slips away' when it heels). The board I use makes an amazing difference, and that is no joke. I can now point to windward well enough to not look like I'm going backwards when sailing next to bonofied racer/cruisers. If there is one modification I am most pleased with it is by far the new board. Maddmike

Maddmike , I am impressed with what you have done.Maybe it will change skeptic ideas about what can be done with the Mac for the "true blue". It reminds me of people laughing at the "4 minute mile" until Roger Banister came along.

You obviously travel alone as space seems restricted with all the hardware. I am sure a lot of owners out there, would be interested to hear about any weak points regarding the structure or hardware you have encountered.

Balu,

Actually the boat is fairly clean and open inside (at least I think so). It gets very good airflow while on the hook in the tropics (ever noticed there is usually an island in front of you to make dust & block the trades?), I'm not sure the 'M' would be as good with the head restricting airflow (Maybe someone can advise me on this?). Tahoe Jack might be a better, more objective source on if the boat feels 'crowded', as I tend to have a rather self-focused point of view. My table rotates up & I have a 'full board' under the aft rug that I use for making the sette into a extended double bunk (never said I didn't meet any girl types along the way, in fact this was the #1 thing that added to my origional timeline). The forward birth is now a single, but the aft birth (which I usually use in cold climates is still a nice double (less some headroom for the A/C.) Also I have a 'tent-cot" which sits on top of the davit tubes that folds out and gives you an open air (netted) temp. 'aft cabin'. 3 singles or one couple and 1 single do quite nicely. By the way, the head door was cut down the middle and folding door sections were added to each side (all use piano type hinges), so when you open the head you get double the usual space & still have some privacy. Maddmike

Maddmike:

Regarding the CB mod:

Looking at your mod Maddmike, I see that there is a gap between the end of the CB and the bottom of the hull.

What is the benefit of having that gap rather than having the tail of the CB come up flush with the bottom of the hull?

What would be the minimum (vertical) distance of the CB/keel extending down from the hull (in the water all the time) to really improve to wind sailing?

MaddMike,

Thanks so much for the pics of your centerboard modification.

It looks like your CB has rounded edges all around, but not much in the way of a foil shape. Do you think if it had more of foil shape the performance could be even better? Do you think a thinner board if it was as strong (perhaps a metal plate) would work just as well? Can you provide a little more detail as to how you added and attached the aluminum plates to increase the strength of the CB trunk?

Thanks again for taking the time answer so many questions. Your experience is really helpful.

MadMike: This topic has come up before, and it sounds like you solved it in the easiest way? I had thought about a water bladder to separate saltwater from freshwater, but your way is simpler. The thing is what kind of watermaker, and does it make enough to refill the partially empty ballast tank in a timely way. i.e. If your 500 miles offshore with a partially filled tank, and a storm approaching?? what then?

I think the M sideslips on a tack too. It is 15-1/2" wide x 67" in the drink.
As the X is so similar, Do you think adding a 100 lbs. of lead shot in the bottom 12" might help it stand up a little better, or : Not worth it? Any feelings about this? It only lowers the center of gravity a few inches, but
It would add leverage. Archimedes lever, right? I think the M can race the other similar sized keelboats downwind, but on a tack it will lose out.

That is one problem with the M. You can't just board to the front of the M's daggerboard...

Zeno's Arrow's watermaker is a Pur model 40, 12V unit (with backup hand-pump suvivor 06). The unit does not provide anywhere near enough volume to re-fill a partly empty ballast tank. (I usually top the tank off with fresh water when gassing up. I also have a 2 x 12 gal. domestic supply. Therefore the ballast supply is only used for back-up & emergencies. If I were to get into a position where I needed to quickly fill the tank I would flood it with salt water and then later 'recycle' the ballast tank water back through the watermaker to remove the salt (which would be less than that in the surrounding ocean as it would be diluted with the tanks remaining fresh water.

This gap only occurs when the boat is on the trailer as I do not want the board bouncing into the hull as the trailer goes down the road.

As for a bit more of an airfoil shape. This is only model #1, which was an experiment. Model#2 will have a more sophisticated shape, now that the concept has proved itself out. That is unless I eventually go into a 'M' model boat, which I have been considering (and yes I do have some ideas how to get around the centerboard physical restrictions. Main reason for considering a M is that I believe I've carried the X about as far as practical and besides, I would really like to start designing, building and testing some 'M' centerboards & specific racer/cruiser 3DL sails that I believe would make the boat rock! However, that said-While I can build the board & sails gratis, I seem to be a bit short for a new boat. Oh well, maybe someday.

Maddmike,
Can you elaborate on Model #2 CB? Materials, differences from Model #1, improvements over previous model. Any drawings?

Maddmike,
Can you elaborate on Model #2 CB? Materials, differences from Model #1, improvements over previous model. Any drawings?

Sorry no drawings as I do not have a scanner here in Sri Lanka & would rather make my mistakes in private anyway.

However, As for board # 2, some thoughts to consider:

Some of the comments made in the modification section are very well thought out & on target. Hydro vs. Aero (past Fire Protection Engr. educated type-lots of H20 & also flexable wing hang-glider designer tester type-still alive must have been somewhat OK at it); both used the same reynolds numbers, no diff. L/D, parasetic, induced drag, etc.

The initial board was designed w/o lift in the horz. position for the reasons listed in your mod. section. However, keep in mind there is such a thing as neg. lift (ask any NASCAR driver), adjustable angle of attack, and anhedrial(sp?) airfoils. enuff said for now. (sorry for the mis-spellings, you get bumped off the net alot here in Sri Lanka and tend to write as fast as possible to avoid doing your responses over and over.

Could somebody be kind enough to post links to the pictures of Zeno's Arrow mods or info how to get to them?
I can not find them on macgregorowners.com site. Where are they???

www.macgregorowners.com
Forums (left top of page)
#2 on dropdowm menu (macgregor forums)
click; Mac Site Talk
click;Macgregor 26X Off-shore Crossings

maddmike,

Thanks a lot!!!

I was searching everywhere else I guess.