The Mast

alambertfl · Post by **alambertfl** » Jan 8th, '12, 19:31

Hello Fellow CD Owners and my Advisors:
I have just launched my 78 CD 25 after refurbing her for around 6 weeks on the hard. She was hurricane damaged and I have had lots of questions and received many good answers from all of you, my fellow Cape Dory owners. Well, I have one more question.
Now, that the boat is in the water and sitting in a slip, it looks to me like the mast is angled to the rear somewhat. I have adjusted the forestay as tightly as it will go, and of course loosened the backstay and rear side stays accordingly, but it still "looks" like it is leaning to the stern of the boat. Unfortunately, I have nothing to compare it with, so I really don't know if everything is okay or not. I would appreciate any advice you may be able to give me on how to check to see if the boat is properly rigged. I am seriously considering calling in a professional rigger to take a look, but before doing that, I wanted to get your opinions. Thanks in advance for all your responses

Oswego John · Post by **Oswego John** » Jan 8th, '12, 21:57

Hi Sonny,

If it is determined that there is too much rake in your mast, you may find that it is easier and more cost effective, rather than change the standing rigging, to move the mast base slightly aft.

Good luck,
O J

Jerry Hammernik · Post by **Jerry Hammernik** » Jan 8th, '12, 22:13

I hate to disagree with OJ but I don't think moving the mast base is either easy or a good idea. It is tied into the structure of the boat where it is. Sail the boat first and see if it has excessive weather or lee helm. My guess is you may need to shorten the headstay. I had a 1978 CD 25 and that was what I had to have done. Not an expensive proposition. But you need to see how she sails before you start to make alterations. One key for the 25's of that vintage is they sailed much better with a full water tank. That weight up in the bow (tank was located below the V berth) made a big difference in the trim. I'd make sure that was done before anything else.

Great boat. Had mine for 20 years before getting a 28 and it was a way better sailor than I was.

Maine_Buzzard · Post by **Maine_Buzzard** » Jan 8th, '12, 22:22

Hi Sonny,

On a very calm day, hang a 5 - 10 lb weight on your new main halyard, just above the boom. I use a heavy sash weight from an old window. The distance from the weight to the back of the mast is about the rake of the mast. 3 - 6" of rake is not out of bounds.

You can check the trim of the boat by putting a level in the cabin sole. If it slopes one way or another, lift the level until the bubble is centered and note the gap. (I'm guessing that your sole is level to the loaded water line. Most are...)

Say you have a 4' level, and need to lift it 1/2" at the stern to get it level. Your mast will have about 6X extra rake back (3") because the boat is squatting at the stern. (Also guessing your main has a 24' luff.)

Do you have an outboard on, and extras in the aft lockers? All that junk in the trunk drags her booty down...

Anyway, go by feel. Center the mast in the stays, and try it. If she has strong weather helm in 15+ winds, move the mast back a few inches and see how it reacts. Too light, move it forward. It's art, not religion...

Other trim suggestions. Shoot for 4" +/- of headstay sag with a genoa in a good wind. Go to the bow sailing hard on that 15 kt wind and sight up the forestay. You should see a curve with about 4" in the center of the wire or furler. Tighten the forestay and backstay to set this. I tend to set my shrouds so there is no wobble in the lee upper shroud when on that same mythical perfect upwind as the forestay check, and look to see that the lowers are not flapping.

You can buy a Loos gauge, but my personal opinion is that they serve more as a confidence builder to those who just want to read a number in a chart and turn a dial. Your rig will not crash to the seabed because you failed to set the uppers to 10.75% of yield strength... If another CD25 owner in the area or the rigger helps with the initial setup, you will be free to experiment and know your boat better for it.

Duncan · Post by **Duncan** » Jan 8th, '12, 22:33

Jerry Hammernik wrote:... But you need to see how she sails before you start to make alterations...

A quick second on that one - I made quite an effort to trim out a stern squat on a previous boat, only to find that she got bow down out in a breeze.

I'll second Maine_Buzzard's method with a weight on the main halyard, too. I hang a 12" wrench off it, to get a quick idea of how vertical the mast is.

Oswego John · Post by **Oswego John** » Jan 9th, '12, 00:57

Oswego John wrote: If it is determined that there is too much rake in your mast, you may find that it is easier and more cost effective, rather than change the standing rigging, to move the mast base slightly aft.

As previously stated, "If it is DETERMINED that there is too much rake in your mast ........."

There are many things that determine the severity of the rake. One of the standard methods, as mentioned, is attaching a weight to the main halyard and using it as a plumb bob to measure the amount of rake

It makes a lot of sense to sail the boat first to see if there is a reason for the look of excessive rake. Maybe with the balance or the condition of the suit of sails being used, or for another condition, possibly a PO set the rake at that degree for a good reason.

There is a cost for fittings and some labor involved if shortening one stay and lengthening another. The thing to be careful of is lengthening the stern turnbuckle to such an amount that there aren't full threads holding the stay to the turnbuckle, to the mount. You should wind up with adequate adjustment in the bow turnbuckle, too. Not shortened as to jamb the pins together.

For a mast that is keel stepped, the ratio of the distance between keel to the cabin roof and the distance from the cabin roof to the tip of the mast is such, a fraction of an inch of movement on the mast shoe will result in several inches of travel at the mast tip.

I have found thet the original factory location of the mast base is reliable. Most often, I have found that changes at a later date by the owners, for whatever reason, result in new problems.

Another thing to mention, don't put blind faith and trust in the existing waterline. It may have been changed from the original line. I'm not saying that a change is a bad thing, as I hope many cruisers will tell you that they changed theirs to compensate for the extra provisions and gear they stow.

My last comment (on this post) is check with a plumb line and look for any curvature in the mast.

My thoughts. Good luck.

O J

Steve Laume · Post by **Steve Laume** » Jan 9th, '12, 10:43

Sail first, worry later.

I would sail the boat a good bit before I started to change anything. Make sure you are not over trimming the main as that will also induce weather helm that will not be related to mast rake.

Measuring the rake might be interesting, if you could compare it to other CD-25's that are well tuned. Your true concern is not how much rake you might have but how well the boat sails.

If you do determine that the rake has to be changed I would opt for altering the stays instead of the mast step. I doubt anyone moved the step to create the problem. I am assuming the mast is deck stepped. If keel steeped it would be a different matter.

If you have hank on sails you could even change the stays without removing the rig. The head stay could be removed with halyards in place to hold up the rig. It could then be shortened with a new turnbuckle screw. If the back stay needed to be lengthened it could be accomplished with a toggle.

The proof will be in the sailing and it is way more fun than measuring things and possibly even worrying about something that might not be a problem, Steve.

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