Mast rake on a PSC 37

johnbanfield · #1 (**permalink**) 10-24-2011

Hi,

I think my mast is raked too far back. Can someone with a happily tuned rig please hang off their main halyard and see how far back from the gooseneck it comes?

When I do it it is about 20 inches. I suffer from rounding up quite a lot.

Thanks,
John

niftynickers · #2 (**permalink**) 10-25-2011

According to the mast tuning instructions published on this forum several years ago from Don Kohlman previous president of Pacific Seacraft the mast should in column,that is not raked.
I had my rig tuned last year by a pro rigger (first time in 20 yrs)and the boat sailed better than ever.
You may be able to find the tuning instructions in the archives.

Good luck,

Dianne and Chuck Burke S/V NiftyNickers C37 #139

DaveMancini · #3 (**permalink**) 10-25-2011

Hi John,

Don Kohlmann, former president of PSC, wrote a really thorough piece about rig tuning PSC's. You can find it at this link:http://www.cruisingyachtsinc.com/dkrigtune.pdf

In there you will find that he was fond of a little rake and also describes the need for prebend.

Good Luck,

Dave Mancini
PSC34 #305 s/v Swan

johnbanfield · #4 (**permalink**) 10-25-2011

That's great, thanks!
It is all making more sense now. I was having a beer with a 34 owner the other day and told him the monitor couldn't hold against the weather helm in strong gusts and he looked at me funny. The rounding up We have been getting in heavy weather has actually been dangerous.

I'll reduce my rake, ideally to a couple of inches, as far as I can without cutting foils or wire today.

Thx again,
John

DaveMancini · #5 (**permalink**) 10-25-2011

You welcome John,

Our mast is raked about the fore and aft width of the mast, which induces just enough weather helm to keep the balance lively going to weather. Of course, the amount of rake your boat will require will depend on its own unique balance.

Dave

johnbanfield · #6 (**permalink**) 10-27-2011

Hi all,
Well, I moved it forward quite a way, to about 5- 6 inches rake. We still have a little weather helm as desired, but I think it is much better. I moved about 4 inches of stay length to the back in the form of two extra toggles, so this equated to about 12-14 in of masthead movement.

The boat is better balanced and I can carry more main,
We were a bit stern down, and this has improved, and
I can stand easily under the boom now.

Muey bueno!

Cheers,
John

RichH · #7 (**permalink**) 10-27-2011

John
I sail a similar design boat. Weather helm also (perhaps principally) depends on the 'shape' of the mainsail and where the position of maximum draft (POMD) occurs. The POMD can be shifted fore/aft by adjusting halyard (or cunningham) tension and that will establish the amount of weather helm desired.
A woven dacron sail needs to be additionally tensioned along the luff AFTER being 'raised' to take the proper shape that the sailmaker 'designed' into the sail .... OR if the sail is aged, the luff boltrope probably has 'shrunken' ... all leading to 'weather helm.

Weather helm is function of mast rake AND mainsail SHAPE. Here's an article I wrote some time ago about how to 'properly' raise a woven dacron mainsail to obtain 'as designed' shape and 'proper' weather helm: How to properly RAISE a woven dacron mainsail - SailboatOwners.com

hope this helps. ;-)

DaveMancini · #8 (**permalink**) 10-31-2011

Skygazer,

Sorry, we were at sea. If you mean "roll acceleration," lower is definitely better. I'll try to contact John and see why the database is not available. It is definitely informative.

Dave