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View Full Version : Gunter rig, mast rotation.



chrisring
07-10-2015, 10:02 PM
I am currently building a Bob Baker designed Puddleduck. Its an 8' pram with a small unstayed 35 sqft gunter rig, no jib. All three sticks are 7' long. I've made a mast step already with a round 1 1/4" dia tapered hole. Today I get out the spar plan, and see he has noted the butt end of the mast has a square tenon. I am not one to make changes to a design, but I cannot think of a reason the mast in such a situation should not be allowed to simply rotate. The step will be stronger with a round hole, and it seems to me if a young sailor does something foolish, a rotating mast would let the whole rig run out ahead without something breaking.
The gaff has a 1/4" pin at the lower end that inserts into an angle bracket screwed to the mast, and there is an "8" shaped bracket on the gaff that fits over the mast head.
I am curious if anyone has an opinion whether I am missing something here.

BBSebens
07-10-2015, 11:36 PM
So, not a sliding gunter, but rather one that you set at the ramp and secure in place? Seems to be simply a way to get a two-piece mast that fits in the boat.

Apart from that, does the boom not provide sufficient freedom of movement? A rotating mast probably won't change much, other than having to be mindful of the halyard.

chrisring
07-11-2015, 09:25 AM
The sail plan is not as thorough as the spar plan. There is no indication of a halyard, reef, offset or notch in the luff at yard, or battens (although moderate roach is drawn). The yard is afixed with the bracketry so like you said, is an extension of the mast. The boom has jaws that are drilled for a parrell and downhaul.
I am envisioning the sail being laced to the yard and boom. At the ramp, you would step the mast, impale the topmast with sail and boom attached upon the bracketry and secure with the downhaul (cleat is drawn on the mast). Then secure the parrell and the luff with a few beckets.
It seems to me running off the wind, there would be extra strain on the bracketry and twist along the luff. The "8" shaped bracket at the masthead could rotate, but the pin at the heel of the yard being fixed would result in a kink or twist in the luff when off the wind.
I only have experience with sprit rigs and sprit booms where the mast rotates and they work like barn doors, so I am unfamiliar with the concept of a fixed mast. Maybe I am overthinking this?