Travelling OffCenterBoards

Board in stowed position.

NOTE: Many of the aspects of the system presented below have been improved. Please start with this post for a better overall picture and video of set / stow procedures.


Travelling OffCenterBoards

We love Big Windows, and we love OffCenterBoards (OCBs). In our case, they are like leeboards, but prevented from winging out on the windward side... this lets them stay down and effective on both sides, with no tending between tacks (the windward leeboard must be raised, lest it drag away from the hull, sailing 'broken winged').

But this presents a problem. When stowed, OCBs go more or less horizontal, and pretty well eliminate our view.

What to do? What to do??

After considerable head scratching and a false start or three, we came up with the following system...

Approximate component locations, Position Line not shown... see schematic for close-up.

Schematic for components above and aft of Window.

The general idea is that the board hangs by the Lanyard, from a block running along an SS Cable, high on the hull.

The Board's position is controlled  via the running Position Line, which is a loop through the EyeBolt and a shackle at the forward Bracket, with both ends fixed at the shackle of the inverted, Running Block. Pull aft on the upper portion of the loop, and the Board rolls forward, and visa versa. To fix position, jam upper portion of Position Line in the Clam Cleat. This is oriented to prevent the line from slipping forward, and therefore preventing the board slipping aft; no forces make it slip forward.

Additionally (as seen in profile in the first schematic) a second SS Cable forms a slot between itself and the Board Guard. The Board fits in this slot during daily use, and is prevented by the cable from winging out on the windward side. Leeway presses the board tight against the guard on the leeward side, in the manner normal for LeeBoards.

To stow, release the Position Line. Using the Board Retrieval Line, raise the Board clear of its slot, and roll aft. Pull up to lodge the stopper knot in the Board Retrieval Line in the crotch of the Pinch Cleat, then make the fall fast around the Horn Cleat.

To deploy, reverse the procedure... Raise the end of the Board and angle the Board Retrieval Line aft to clear the Pinch Cleat. Roll forward until over the slot, and lower. Position with Position Line, and fix in Clam Cleat. Trim Board Retrieval Line to desired Board angle, and make fast on Horn Cleat.

While this was intended to be a prototype, it has worked astoundingly well. It takes about 15 seconds to stow or deploy, per board.

We used available 1/4 inch SS Cable, which looked a tad light. We have heavier backups, but sofar, no problems in high end of gale conditions. The brackets for both cables absorb a huge amount of stress. They should be very well built and strongly bolted to adequate structures. We used aluminum T-channel, bolting the cross-bar of the T to the hull, and shackling to a hole drilled in the post of the T.

The boards are pretty heavy for dead-lifting. I'd like to build lighter, surfboard style. For larger installations, the upper cable could be carried aft, and the Board Retrieval Line mounted on rolling blocks to provide purchase and full movement.

One of the fringe benefits of this system is that we can really bring the Center of Lateral Resistance aft. When running, for example, the boards can be set aft in the slot for improved directional stability (not needed on square boats, particularly, but ya never know).

For a fixit solution, the whole thing worked out pretty well!

Board in use position, cocked up by dryout... we used it to keep the boat from drifting as tide went out.