Javelin mast step
- Thread starter John Stevens
- Start date
Hope this helps. I don't know what year I have, but I think it is 1968 or so. The step is actually just sitting on the fiberglass ridge - boat was on a mooring, storm came up, starboard turnbuckle came undone, shroud came loose, and mast was only supported by the hole in the deck, wave action tore the step out of the ridge. The three fasteners you can see in the pic are bolts, not screws, but I can't figure out what they were bolted through. I think I am going to cut something to fit below the mast step plate under the fiberglass (longer than the plate to help spread strain) and fix it with 3M 4200 to the underside of the fiberglass, then screw down the plate. I also intend to cut the mast and install a tabernacle, as the mast is too much to handle by myself.
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Mast Tabernacle
I said mast step but really meant Tabernacle. I have the "cut" mast with a plate at the tabernacle that is attached to the small section of mast below the deck but moves freely in the hole. Wondering if it should move around like that. My DS1 had a step on top and bottom and they were bolted together with the deck in between, there was no movement.
John
I said mast step but really meant Tabernacle. I have the "cut" mast with a plate at the tabernacle that is attached to the small section of mast below the deck but moves freely in the hole. Wondering if it should move around like that. My DS1 had a step on top and bottom and they were bolted together with the deck in between, there was no movement.
John
My tabernacle is flush with the deck, as was my DS1. The Javelin lower mast portion has a bit of wobble at the hole. Not sure if that's normal. My DS1 was bolted through and didn't move at all.
Sorry I had the wrong photo- I want to install the tabernacle set up. Even on a mast set up without the tabernacle, where the mast goes through the hole in the deck, there is some play, but I think as most strain or force is carried through the shrouds and forestay so as long as they are tensioned properly I wouldn't think some play at the hole in the deck would matter. Do you have any pics-always curious to see another owner's set up.
Here are a few shots of the mast step and tabernacle. I can move the tabernacle from side to side about a 1/4 inch, 1/8 inch each way. Is this normal? Again, on my DS1 the tabernacle was bolted into the bottom part of the mast and I believe through the deck, there was no movement at all.
John
John
Others may have more info, but I don't think you should have any concerns. Great pics, by the way. If you are still worried, a little padding stuck in around the hole would help eliminate the play, but I don't think the deck is really supposed function as a structural support for the mast. I think that the job of supporting the mast is the step at the base of the mast, the tabernacle, and the stays. I think you could cut a hole the size of Frisbee around the mast and with the step and stays in place the mast would be perfectly strong.
The mast needs the support of the deck opening to be structurally supported. A little play is not a problem (1/4" or so), but much more (that "Frisbee-sized" hole) than that, and you now have a potential problem at the hinge. Without the side-to-side and fore and aft restraint of the deck hole (proper tem: "Mast Partner") the mast will move around too much at the joint created by the hinge, this can ultimately cause the screws or rivets that secure the hinge to the mast extrusion to work and ultimately fail. Again, the small amount of space around that Javelin mast should not be a problem, but if the hole were Frisbee size, the mast joint there could move side to side or fore-aft by half that diameter and eventually cause failure of the mast at that point and/or rip the lower mast-step off the support beam it screws/bolts to.
Compression of the mast, due to resolution of forces (wind pressure on sails, offset by pull of the shrouds, wants to push the mast down through the deck. Since the mast is prevented from moving down by the lower step, the point where the hinge is will try to release that stress in another direction, if the mast is not restrained at the deck (where hinge point is), it may move sideways (this effectively "shortens" the mast, since as that point moves to one side he top and bottom of the mast get slightly closer together) as a reaction to the downward push of the mast due to restraint from the shrouds.
Sorry, I know what I'm trying to say..... but, realize that it is coming from someone with a lifetime of sailing and a mechanical engineering background. Just thing of standing a pole up like a mast, then push down on the top, it stays pretty well as long as you don't introduce any sideways force (like tilting the pole while still pushing perpendicular to the ground). Now, stand that pole on a shorter pole (or tall block or brick), push down on it as before..... you will find that you are OK as long as that lower pole or brick stays vertical, but now tilt the top pole a little bit.... and the lower pole/brick will most likely kick out to one side and fall over.
The tall pole is the mast, the short pole is the section of mast below the hinge.
Compression of the mast, due to resolution of forces (wind pressure on sails, offset by pull of the shrouds, wants to push the mast down through the deck. Since the mast is prevented from moving down by the lower step, the point where the hinge is will try to release that stress in another direction, if the mast is not restrained at the deck (where hinge point is), it may move sideways (this effectively "shortens" the mast, since as that point moves to one side he top and bottom of the mast get slightly closer together) as a reaction to the downward push of the mast due to restraint from the shrouds.
Sorry, I know what I'm trying to say..... but, realize that it is coming from someone with a lifetime of sailing and a mechanical engineering background. Just thing of standing a pole up like a mast, then push down on the top, it stays pretty well as long as you don't introduce any sideways force (like tilting the pole while still pushing perpendicular to the ground). Now, stand that pole on a shorter pole (or tall block or brick), push down on it as before..... you will find that you are OK as long as that lower pole or brick stays vertical, but now tilt the top pole a little bit.... and the lower pole/brick will most likely kick out to one side and fall over.
The tall pole is the mast, the short pole is the section of mast below the hinge.