Tuning Guide - Osprey

This guide is designed to give you the basic measurements. It is worth experimenting to find the settings that work best for your boat and sailing technique.

Mast Rake

To measure the mast rake hoist a tape measure on the main halyard then hold it down the back of the mast and adjust it so that it measures 20’ to the top of the mast band at the gooseneck. Measure the mast rake to the top centre of the transom with the rig tension at 400 lbs on the shrouds and the strut in neutral.

Rig tension (measured on shrouds) 400lbs

Pre Bend/ Spreaders

Length 475mm (from sidewall of mast to shroud) 440-460mm for light crews.
Sweepback 160-175mm (from back of mast track to a line between the shrouds).

You should have roughly 25mm of prebend on 24’ 6” of mast rake, measured as described above. Depending on your hull the spreader sweepback may vary. I suggest using the sweepback above as a starting point and adjust as required. The pre bend is the important figure not the sweepback.

Deck level or Strut Bend Control

Fairleads

Good luck on the Water!