mast head jumper arrangements

[Tim Stewart]

Can anyone tell me how to tune a mast head 'jumper stay' arrangement standing rigging, and where in the sequence of rig tuning do you tension the 'jumper stays' (first / last etc).

Usually the struts are angled forward so I would have thought that if you tensioned the 'jumper stay' wires, then you would put negitive bend into the top of the mast.

On a Westerly 33 Ketch mizzen mast, there doesen't seem to be a backstay counteracting the induced negative bend of the 'jumper stays'.

Can anybody advice with the tuning on this yacht.

Thanks

Tim