Mast/bend/rake
I'm late to this post, but I see the discussion of mast rake vs. mast bend.
Here's the skinny: Your rake is fixed...as the Oceanis series have a fixed length forestay (unless swapped out aftermarket). This means the amount of rake (the inclination of the mast fore and aft) cannot be changed.
Most of this vintage boats...361, 393 etcetera have around 12-14" of rake depending on the model. This can be measured by hanging a bucket of weight from the main halyard..it will hang straight down and you can measure between the plum line of the halyard and the mast. Measure at the boom. Halyard will be 12-14' aft of the back face of the mast. This is conditional of course on the boat floating perfect..so expect some variance.
Mast bend: On these rigs mast bend is induced by the cap shroud (upper shroud) tension. As you tighten the caps they they load up the spreaders and since these are angled aft, the compression loading of the spreaders pushes the middle of the mast forward..bending the mast. The tighter they are, the more bend you will have.
The AFT lowers are also sometimes called checkstays...as they come into the mast at spreader height and keep the mast from bending too far forward.
The babystay isn't really used to bend the rig fore aft but to help prevent the middle of the mast from moving backwards (as can happen in very rough seas) and in doing so keeps the mast 'in column' and is much safer.
The question of mast bend depends on two things first and foremost:
1. Roller furling main?
2. Classic main?
The furling mainsail rig should be set up with a minimum amount of mast bend. Most riggers keep it down to 1-1.5" of bend fore and aft. Anymore than this and you will start to interfere with the mainsail furler and extrusion inside the mast and the sail will not furl smoothly.
3. For the Classic Mainsails mast bend depends largely on how full or flat the mainsail was designed or has become. Our Neil Pryde mains are designed for about 3-3.5" of bend....but this too is a moving target, because if you sail in San Francisco for instance in the summer...you'll want a 'flatter' mainsail...and this can be easily done by increasing the mast bend and thus flattening the sail shape.
Conversely...Long Island sound boats might want a bit more power for light air and might set up the boat with less bend which makes the main fuller.
bob pattison
Hi All, I've posted this on a couple other sailing sites, but I should have posted it hear first.
I read through Seldon's mast tuning guide, as well as some other less formal guides when tuning my mast recently, and I got all the shrouds/stays tensioned correctly. this being my first time tuning a mast, however, I'm second guessing myself. The mast is in column. Is this amount of mast bend appropriate?
I do not have a backstay adjuster.
Any help is very much appreciated.
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