We just purchased a mast butt adjuster like the one at APS ... J24 Mast Butt Adjuster w/ RF Sealoc Adj. | APS . How do we install it? Should the the adjuster point to the bow or aft? If aft do we attach it to the plate the mast is on or the bulk head?
I tried installing it on the I beam which worked at first but then when I needed to move the mast back there wasnt enough room to get the mast where we wanted it. I ended up moving it to the bulk head to get the room I needed. I am comfortable with this since it doesn't hold the load when sailing. The screws through the plate itself take the pressure.
In general, most teams have the turnbuckle style mast-butt adjuster configured aft of the casting, and through bolted to the main bulkhead. In operation, the more highly loaded "adjustment" is moving the mast butt aft, and for this purpose the turnbuckle simply works better in tension rather than in compression. I've also seen very good teams deploy the turnbuckle ahead of the mast with a thin sheet of HMDP or similar "slick" surface to reduce the amount of friction between the butt casting and the i-beam. I think in this configuration you'd want to make sure your adjustment range is utilizing the least amount of exposed threads as possible, so that you avoid the possibility of the turnbuckle falling out of column (catastrophic) when the butt isn't pinned during adjustment.
This is a J24 we're talking about (and the bulkheads are positioned by human hands over a period just shy of 40 years), so some owners may find that the minimum length of the turnbuckle itself with the attachment method to the bulkhead might still not get the mast butt far enough aft on the i-beam if looking for more than about 2.25" pre-bend.