X boat's Centerboard position.

[Fairwinds]

I'm considering the purchase of an "X" model and have some doubts about the freely swinging centerboard used in this model. In another thread, Frank C dismisses my concerns as unfounded, that the CB, when fully lowered, holds and maintains this position without any means or provision to lock it in place. I have considerable experience with swing-keel boats and it has been my finding that if a centerboard can move, it WILL move.

Under boisterous sailing conditions, having the CB moving around on its own is not the ideal situation. I'm wondering if other owners have had any problems with the free-to-move centerboard.

Since there is no way to tell whether the CB is fully extended or not, (other than "feeling" the lift line) perhaps the difference between a 90 degree centerboard angle and a 30 degree rake is of no concern..

(Search terms: CB depth)

[nedmiller]

If you forget to raise the board when loading onto the trailer, you hear a thunk and the line goes slack. I've never seen the line go slack while sailing.

Ned

[Billy]

OK, I've been watching this and might as well jump in. I have had my X since '01 and I have never known the CB to come up or move on its own from water underneath. Once that CB is down and any sort of lateral pressure is applied, it's not easily coming up even with the line.

The only times my CB has ever retracted is when struck with immovable objects. Once when swept over a reef at Andros, Bahamas. Only 12 inches of water between it and my X. The CB and the Suzuki 140 kicked up. Only damage to the boat was a 7 foot long narrow scatch in the gelcoat on the bottom. (Looks like when your car gets keyed.) These boats are much tougher than people give them credit. Anything other than a retractable CB and the boat would have probably rolled.

The only other times the CB comes up is when sailing in skinny water. Once deep again and the lateral force is reduced, the CB drops back down.

I have to side with Frank on "concerns of the CB moving around on its own". Hasn't happened to me and I've been in some crazy situations/conditions (the Dry Tortugas, Keys, Abaco, Andros, Bimini, NC Outer Banks including Pamlico Sound). You'll probably have a bigger concern getting it up when you want rather than keeping it down. I know--I broke my CB off at the trunk, but that's another story.

And as for the "improved" rudders mentioned earlier------aren't all aftermarket products advertised as improved?

[Duane Dunn, Allegro]

Seven years now with the X and I have never had the centerboard move on it's own. The problem is more often the opposite of it not wanting to move when you try to raise it. You have to get all side loads off it to raise it even a bit.

My previous boat had a 500lb swing keel. It had a lock pin that kept it in the down position. This certainly wasn't to keep it from moving under normal sailing conditions. It was to keep it from crashing back down on the hull if you turtled the boat.

The X board is not a weighted swing keel like many boats have. It is a light piece or water filled fiberglass like a day sailor would have. It is made to twist and jam in the trunk under any side loads and does so very well. There are also many modes of operation when you don't want the board full down both under power and sailing. I have my lifting line marked every 2" so I can easily select the angle and depth of board I want. As mentioned the kick up function of the X board is a handy feature as well, something that was lost with the M daggerboard.

[ronacarme]

So far the CB stays down all by itself despite being lite and having no holddown bolt, unlike my old Venture 17. However, if I somehow manage a 180 degree capsize of my always fully ballasted X, I don't see its CB position as my primary concern.It seems to me that, as to its unballasted CB, the X is simply a big CB dinghy, and as to capsize, the CB is not the issue.One man's opinion. good luck. Ron

[Fairwinds]

I am just having a hard time understanding how a 6' long board, unsupported except by a single pivot bolt and side load friction at its top end will remain at a 90 degree angle to the hull (or 80 degrees, whatever) with 6 knots of water pressure trying to push it (partially) back up into its trunk. Lets say you lower it at zero knots and head off on port tack. The board locks itself in position by some engineering process I don't understand. Fine. Then you decide to switch to starboard tack. For a moment, as the boat come across the wind, the side load on the board is released and it's free to move back, pushed by the water flowing past it.. heading off on starboard tack, side loads once again jam the board in position. BUT WHAT POSITION?? Everyone says the CB does not move, it stays in the fully extended position. The lift rope never goes slack on its own...

Does THIS statement apply: "What are you worried about? So what if it moves a little, few people notice it and it doesn't hurt anything. The CB position is not critical." I can understand that and I can live with it..

[Night Sailor]

I think you have a good question. I can't explain why it works the way it does, but I've never had any indication that my centerboard has lifted except when hitting a tree trunk or unknown shoal. Because it is so light and unrestrained there has never been any damage. No matter how hard it's sailed, or tacked, my X maintains a consistent feel and motion. Even at just 2 or 3 mph under motro power, I can't always lift the centerboard, but can easily do so if at a dead stop. This in spite of the fact that I put spacers in the hangers to eliminae all side play, leaving only 1/8th inch for the hanger to twist under pressure.

I agree with the others, it's just nothing to worry about unless you find the boat performs inconsistently from one tack or sail to the next. As much difference as it makes when you raise it slightly to meet various lee or weather helm conditions. I'm sure one would notice if it moved and didn't go back to normal.

[Fairwinds]

I wonder if there is some trick hydro-dynamic force at work holding the CB in position...or...I assume there is a single pivot bolt passing through both the CB and the hull (trunk). Is the hole in the centerboard round, a close fit on the bolt, or is it a slot, allowing the board to jam against the hull and self-lock. Then, before you can raise it with the lift-line, you first move it up the slot a little, allowing it to swing back..

Night-sail, why did you shim it? Could you detect it moving?

[Lease]

The answer that you are loking for is indeed related to the shape of the board if what I have read is true.

My understanding is that the X board is a 'gybing board'. A bit like that used on some dinghies, where the shape of the board casues it to cock to weather a little bit when the boat gets way on. Similarly, when you tack, the board 'gybes' on to that tack and cocks to weather again.

My last boat before the X was a Trailertri 680 which also had an unballasted swing board. If the downrope came out of its cleat, it would immediately swing up (mind you, it was timber, not fibreglass), and you would certainly know it in regard to the boat's performance.

I have not had this problem with the Mac, and as others have sid, you can't pull the thing up when you are working even if you want to. You have to head up to wind and then pull.

Whether the gybing board is true, or not, I don't know. But I do know that the thing stays down and when you get into a bit of rig tuning, the boat points quite well.

[Fairwinds]

So it would seem there is some trick engineering in the centerboard shape and it locks itself in place when underway and it works to the point that no one has had a problem with it. I can't argue with that..

And by getting the sails properly trimmed, Lease can coax his boat to sail upwind without embarrassing him. That's good to hear..

On the other end, has anyone had marine growth foul the CB and its trunk to the point the board refuses to lower..You release the lift line and it stays stuck in the trunk..Salt-water boats kept in marina slips for any length of time are going to encounter this nagging problem I would think..

[Zoran]

When running I will pull up my centerboard. Often it will be at 6kt and up speed. I never had any slack in the line that will indicate that the board moved up on it's own. One of the reasons might be that the board in full down position still sits at the (don't hang me if I am wrong for a`few degrees) 60 degrees angle and the gravity pushing the board down is stronger than water pressure pushing it up.

Zoran

[Fairwinds]

A WOOD centerboard would tend to float back up into the trunk by itself. it would have positive buoyancy. The fiberglass CB's used on Mac's will not float, but when submerged in water, I don't think they weigh that much, not enough for gravity to overcome the rearward pressure caused by the water rushing by. Moving water has a lot of friction on any surface..

Perhaps the centerboards contain materials other than fiberglass. Some re-bar maybe. Not enough to be called ballast but maybe enough to ensure that gravity can hold them down...

[Night Sailor]

I've just read an explanation about why the board doesn't move. It's designed on purpose to be a "gybing centerboard" which means it's designed to twist in the trunk so the board makes contact with the trunk sides for support, not be held in place only by the bolt. That means if there is much speed at all, the board will twist and jam, whether under power or sail. The advantage to making them this way is more power at larger angles of attack. Thus the X sails better than other boats would on the same large angle during a close reach. The disadvantage is at larger angles you cover more ground, although at higher speed. And, when anchored, it makes noise clunking from side to side. Another disadvantage is that you can't motor with the board all the way down because it easily gybes and makes the boat hard to control. See:
http://www.philsfoils.com/designTips.html#gybinghead

[Craig LaForce]

WHen sailing with the board down, the lateral pressure on the board far exceeds any forces trying to lift it unless as was stated above, you hit bottom.

Sorry to hear about your last boat. Those photos are heart breaking.

Under sail, the 26X is a pretty stable riding boat, but at anchor it is very jumpy and the centerboard clunking is pretty annoying. Kinda like trying to sleep on a bucking bronco.

The mac is a great a boat for a lot of things, but if you like to anchor out a lot , I would see if you can try one out first to see if you can tolerate the action.

Mad Mike put some kind of ama on his boat, that might have given more stabilty at anchor as well as a sailing enhancement.

[Zoran]

The fiberglass CB's used on Mac's will not float, but when submerged in water, I don't think they weigh that much, not enough for gravity to overcome the rearward pressure caused by the water rushing by.

It is heavy enough. There is a difference in pulling the board up when the boat is still and moving. In fact when moving it is always harder.

Zoran