mast position

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Marshall Tonner

I was always bothered by the apparent forward lean of my mast.Last winter I shortened my back stay by 4 inches and moved the mast step as far forward as possible.I backed the fore stay off as far as I could. The net result is the aft edge of the mast is now sitting almost in contact with the deck.The mast appears more vertical but the best part is that I can point higher and there is much less weather helm :clap. I'm thinking to shorten the back stay a little more since it is now "bottomed out" on the turn buckle without being as tight as it could/should be.Has anyone ventured into this area? I like the result but would prefer to see the mast more centered in the deck.Ours is a keel stepped mast, standard rig,wing keel, hull # 899.
                                     Marsh
Holland Marsh    Hull #899   Cormarant II

Ron Hill

Marsh : What you need to check is your mast RAKE aft.
On a calm day take the main haylard an tie a weight (hammer) to it.  The straight haylard should hang about 6-8 inches aft of the mast.  Then you need to tighten the head and back stays so it pretty much stays in that same position.  I also have a back stay adjuster and found I had to take up a bit more on both the head and only some on the back stay. 
It looks like my mast may be slightly touching the aft hole in the cabin top, but I know there is no pressure against the mast!   Hope this helps.     :wink:
Ron, Apache #788

Ed Shankle

Marsh,
I had my standing rigging replaced this year and the rigger made a similar "tweak" to my mast. I noticed the same results as you. Figured I'd see how much stretch occurs this season, then next season, shorten the backstay length if needed, as I also ran out of turnbuckle adjustment room.
After reading Ron's reply, think I'll follow his direction and check the distance of the rake this weekend.

Ed
Ed Shankle
Tail Wind #866 1989 m25xp
Salem, MA

Marshall Tonner

Finally had a calm morning and hung a weight from the main halyard and found the mast to be slightly forward of vertical. Since my mast is already in contact with the deck and appears to require even greater rake, I wonder whether mast bend is an option ? The mast section seems very rigid! :?
Holland Marsh    Hull #899   Cormarant II

Ron Hill

Marsh : I can't believe that your mast is bent!! 
What you needed to do was to loosen all of the stays so when you look at the "rake" that there wasn't a stay that maybe giving you a false reading.
Try again,   :wink: 
Ron, Apache #788

David Sanner

#5
Forward of vertical?

Before measuring vertical the boat must be floating level.

If the bow is a couple inches too low and the stern as high
you'll have lost the 4" to 6" of rake that has mentioned.

Pull some big people out of the cockpit or fill up the forepeak
with too much gear and you'll see close to that change.

I guess my suggestion it to make sure she is floating on
her lines first...  (it would be nice to quantify that someway)

Outside of that, if there is a serious rake issue it's a simple problem
(though not a simple solution), your mast step is too far aft and/or the
hole in your deck is to far forward.  Both unlikely but possible I guess.










David Sanner, #611 1988, "Queimada" San Francisco Bay

Marshall Tonner

Ron, my mast is not bent. I was wondering if bending it was an option. After adjustments it still appears to lean forward even though it's aft surface is in contact with the deck. When I measured with a weight tied to the main halyard, the aft water tank was full, as was the fuel tank, and yet the weight was hard against the mast.
Holland Marsh    Hull #899   Cormarant II

Ron Hill

Marsh : Sorry, I misread your post. 
Bending your mast is possible.  As you mentioned you'll need to shorten the back stay. 
When was the rigging on you boat changed out?  I mention that as 15 years is the rule of thumb and you could just have a NEW shorter back stay made.  Then you could check the aft rake as I mentioned.   :wink:










Ron, Apache #788

Marshall Tonner

Both the fore stay and back stay have been replaced , the sides are original. I'll have the back stay shortened this winter and check my position again in the spring. Seven weeks to go till mandatory haul out and I'm already getting depressed :cry4`
Holland Marsh    Hull #899   Cormarant II

Mike Smith

#9
I've been concerned about mast rake in the past, also - my backstay is bottomed out.  Because of all the variables affecting list and pitch (stowage, water and fuel levels, etc.), I wonder if there is a designated "Flat Spot" on the C34, for instance, the main salon hatch?  If there is, then you could use that surface to level the boat (fore and aft, port and starboard) before making rake adjustments, if needed.  Anyone know if there is such a spot?

Mike

lazybone

Marshall

I could be wrong here but,  increasing (aft) mast rake usually adds to weather helm.  If you think your mast has excessive foreward rake and your experiencing weather helm I would examine the sails and determine if thier the cause.  What kind of shape are the sails in?
Ciao tutti


S/V LAZYBONES  #677

Marshall Tonner

The mainsail is getting old but the head sail is fairly new. My next step over the winter will be to move the mast step even further forward so as to get the mast at least centered in the partners.If the result is not good it wont take much to lift the mast a few inches and put it back .
Holland Marsh    Hull #899   Cormarant II