Mast step, compression Post, chain plates

I am not a boat designer but have a question that only boat designers could answer.

I own a Victoria 18 - a full keeled 18 footer w 650 lbs of balast and 1250 lbs of displacement. They have a pronounced weather helm at anything over 8 knots that requires reefing. Over 12-15 knots or so and the excessive weather helm returns.

I have contemplated whether I could move the mast step toward the bow and reduce some of the weather helm. This could be accomplished fairly easily by drilling the mast step receptacle to allow the mast to sit forward in half inch increments, I would not want to move it more than 1 1/2 inches forward.

As the mast step sits on a compression post below deck, some sort of knee brace would probably have to be built to transfer the load from the deck into the post.

But another Vic 18 owner also expressed concern that the angle of the pull from the shrouds on the chainplates might cause problems down the road. So I thought I would post my question here and solicit opinions.

Would a move forward of 1/2 to 1 1/2 inches be enough or too much?
Would a knee brace on the compression post be a sound plan?
Would the sharper angle of pull on the chainplates be likely to cause problems?

Thanks in advance

 

I doubt you'd notice any change with the mast moved forward a mere 1 1/2".
The knee brace question depends upon many factors such as measurement between keel and step (length of post), but suffice to say 1 1/2" would require no more than a piece of wood attached to the forward edge of the post.
Your problems are not of static balance per se, but shifting balance when heeled.
This is common with boats having more assymetrical fore and aft sections.
If this is the case, you might have lee helm in light conditions were you to move the mast forward (and I mean maybe 6 inches), progressing to somewhat normal weather helm as the wind increased.
It's difficult to say without a lot more information. Some designers are overly cautious in placing the CE (maybe for the same reason car makers build speedometers that read faster than the true speed).
A weather helm isn't nearly so dangerous as a lee helm can be. It's just a big aggravation.
I suspect you could improve the helm somewhat, but not a lot. You might try tilting the mast forward, increasing rudder area, or even flattening the mains'l when the wind increases by using a vang or a traveller. The sail could be old and stretched out too, or of too-light material. Any strong belly in the sail under windy conditions will cause excessive heeling.
Regarding the chainplates, a small angular change shouldn't matter. Nobody gets too concerned when raking a mast a few degrees. It's no different when stepping the mast fore or aft a few inches.

Alan

 

I'm very familiar with the boat your have. It was discussed at some length in this thread.

http://boatdesign.net/forums/showthread.php?t=20293

Having sailed the boat in fleets, most try to over sail the little gal, which just makes her want to lean on her ear and wrestle the helm out of your hand.

If you're used to sailing dinghies or other more initially stable craft, then a Victoria 18 will make you uneasy at first. She sails at much higher angles of heel then most dinghy sailors are accustomed to, which makes them think something is wrong. Get a "incline-o-meter" and check the actual heel angles in different wind strengths. I'll bet it's your unfamiliarity with this type of design, then the design itself.

In you defense, there have been attempts to correct what is deemed "excessive weather helm". A cutter rig addition was offered, which was an attempt to address this, but folks still tried to sail them like dinghies and complained. I've enjoyed my times aboard them and felt they preformed well, knowing what they'll do as wind strengths increase.