I've just acquired a boat with a mangled mast foot. Evidently one of the shackles holding the shrouds on to the chain plate snapped and the mast falling to one side bent the tabernacle beyond repair.
I sail in a costal location so don't need a full stainless steel tabernacle, I have machined up a new hinging mast foot instead. I'll post up a picture and dimensions as soon as I have a moment.
The question is where should the mast foot be ideally placed? looking at the boat is has had several mast feet over the years in differing positions. Does anyone have a dimension from the aft face of the mast to the round crease in the deck where the cabin / cockpit cover meets the flat cabin roof?
What is the relationship between the mast foot and the strengthening beam on the underside of the cabin roof? Does the mast foot sit centrally on this? Do you have a plate on the underside of your mast foot or does it just screw into the plank of wood encapsulated in the grp sandwich?
Any help or ideas will be gratefully received!
(the line in the photo represents the centre line of the strengthening beam under the cabin roof)
I'm embarrassed by the state of Just 17 at the moment, but hopefully, this image will give you some idea of the position of my mast. In spite of what it may look like the 0" position on the rule is at the start of the rise to the cabin door.
Mine is a two berth boat that lacks the cabin beam of the four berth deign. However, you might find that scaling up the technical drawing of the Mk 2 boat or the Mast Bracing page could help.
I suspect that rather than different mast positions, it is more a case of differing design of mast step. Consider the original of mine, (third photo down) compared with the image above with tabernacle fitted.