Repositioning mast step

[Captain Mike]

Has anyone repostioned the mast step in a Cape Dory to conpensate for excessive weather helm. Will the forestay have to be lengthened or shortened. Is it actually possible? How difficult a process? Any discussion concerning eliminating excessive weather helm woul dbe appreciated. Many Happy Repairs and keep your teak oiled! Mike



mattngly@concentric.net

[Ed Haley]

I would try other methods for reducing weather helm. The position of the mast has been carefully designed and is usually not the problem. Try to move the center of effort of your main forward. To do this, you could rake the mast, a simple adjustment made by shortening the forestay and lengthening the backstay (this is assuming you desire a straight mast). To do this incrementally, pick a calm day when your boat is in the water and remove the boom from the mast. Get your main halyard to swing free from the top of the mast to just above the deck, aft of the maststep. Attach a weighted bob (a plumber's bob works great) by a string to the halyard shackle and adjust the length of the halyard until the bob about an inch from the deck. Let it swing free until it stops. Mark a point directly under the bob. Measure the distance from this point to the mast. The greater the distance, the more weather helm you'll have. Whatever distance you measure, try shortening that distance by taking up slack in the forestay and loosening the backstay until the bob swings free over a point half-way to the maststep than before (with both stays correctly tensioned or about 1 inch of give). Put the boom back on the mast, bend on the sails and go sailing. See what difference there is. If you want to reduce the weather helm some more, go through the same procedure. Remember, you do not want leeward helm!

There are other ways to reduce weather helm, such as easing the mainsheet, flatten the jib, hoist a larger jib, reef the main or loosen the leech line on the main. Weather helm can be significantly reduced by correctly trimming the right sail combination.

Have fun!



eghaley@dreamscape.com

[Captain Mike]

I started that way on, Breeze, my CD 22D. When I first sailed Breeze, the mast was vertical and halyard when suspended was touching the mast step. I shortened my forestay to the final thread and lengthened by backstays according, the weather helm was reduced but still excessive. With the mast lowered, I brought the stay to a rigger for shortening. He removed approx 4". Mast re-steped, sails bent and still excessive weather helm. My calculations were more intuitive than factual, or other words- trail by error.
I then step the mast as far forward as structure feasible and shortened my stay again approx 2 to 4". While sailing in perfect wind, I adjusted the rig as you recommended. When the rig finally balanced with only slight weather helm, the mast was inclined forward noticeably. I never tried but I would estimate the distance from step to the plumb bob to be 6 to 8" (more toward 8"). Remember this is forward of the step. These adjustments were necessary to help the self steering windvane (Navik) manage the boat within its mechanical limits. A self steering can not make those abrupt changes as can a helmsman. A boat that rapidly turns to windward and not be successfully managed by Navik. What I experienced before these adjustments to the rig, while sailing under Navik was a constant luffing of the boat. Navik not having enough power to overcome the ability of the hull to weather.
I am moving up and the owner of the new yacht informs me of a tendency to weather as typical of Cape Dorys. I am anticipating making similar changes and adjustments again. I would prefer not to have my mast raked forward at some peculiar angle. I just does not look esthetically pleasing. A forward raked mast is probably not any less structurally. I can not thick of another way except short of moving the mast step. One great pleasure while sailing is given the total responsibility of helmsman to Navik. It creates an entirely different aspect to sailing. Navik has taught me many excellent lessons to better sailing. Any discussions will be enjoyable. Happy Repairs.

Captain Mike, frozen in, in Minneapolis



mattngly@concentric.net

[Ed Haley]

Mike:
Something is out of whack that causes your weather helm and, as you have
probably found out, there are many causes of weather helm. I am not a boat
architect or a designer. I'm just an average sailor. But when you raked
your mast as much as you did and still got weather helm, it sounds like
something in your boat has been changed: mast, sails, keel. The mast rake
is indeed excessive. After all the "tweaking" you did on Breeze, there is
not much more I can offer you. If I had to guess from what infomation you
gave me, I would bet on your sails being the culprit; possibly a baggy
sailshape. You need someone familiar with sailing to accompany you on a
sail, perhaps a sailmaker.

I see you're from Minneapolis. During the summer of 1997 while attending a
seminar at the University of Wisconsin at River Falls, I made contact at the
Wayzata Yacht Club and managed to sail on Lake Minnetonka for a couple of
weekends with Dan Hollinger and his lovely fianceé. I found the yacht club
very cordial and friendly as well as being one of the nicest clubhouses I
have visited. If you know Dan, say hello to him for me.

Best of luck with Breeze.



eghaley@dreamscape.com

[sam]

I had a Westsail 32 years ago and now a CD that I have had for a number of years. Both had weather helm in heavier winds when reaching. I was able to greatly reduce it for only a few $. Get a sail maker to remove the roach of the sail. You wind up with a battenless sail. All that area that used to hang out over the side of the boat on a reach is gone and that is what was causing the weather helm. Notice how long the CD boom is compared to most boats.

You get other advantages: easier to flake the sail on the boom. You can reef downwind cuz the battens aren't there to catch in the rigging. I've done that many times and it sure beats turning up wind and getting wet while reefing.

And no I don't notice any speed difference. For most any point of sail the roach is mostly just decoration.