Join Date: Feb 2000
Location: Annapolis, Md
Thanked 436 Times in 366 Posts
Rep Power: 10
Re: Looking for handling info on '67 cal 30
Without knowing the proposed changes to the rig that you are contemplating, it's hard to give you very much advice. My recollection of sailing Lapworth designs of the era was that the fin keel spade rudder designs had pretty neutral helms and that the foils were large enough that the boats tollerated a lot of rudder angle without stalling the rudder.
1967 was around the time that the original Cal 30 was replaced by the later Cal 30-2. These are very different designs. The original Cal 30 was one of Lapworth's earliest designs for fiberglass, and was a pretty crummy boat all around. These had a short keel(fin keel) with an attached rudder. They tended to have a lot more weather helm and handle poorly in a stiffer breeze.
Like most designers of the pre-computer age, Lapworth was an intuitive designer, whose designs were evolutionary rather than fresh designs. The poor handling of the Cal 30 led to Lapworth's shift to fin keel with a spade rudder. Similarly, his first fin keel spade rudder designs tended to be more tender like the Cal 30, but as he saw the power of fin keel spade rudder designs, the hull forms evolved to have greater form stability.
Like most boats of that era the Cal's were comparatively tender. And while the Cal's were stiffer than many CCA designs of that era, they still tended to be sailed with more heel angle than more modern designs. But, like most boats, with larger heel angles they tended to develop more weather helm and so needed a steeper helm angle to maintain course. That was no big deal on the fin keel spade rudder designs, since they rudder was a 'counterbalanced' geometry, but was much harder to deal with on the original Cal 30. As a result with either design, it was faster and easier on the crew to reduce heel by blading the mainsail, or even flagging the mainsail in a building breeze.
The lack of initial stability makes them a poor candidate for a taller or larger rig. The sailing and drag characteristics, and rig proportions make them a poor choice for a cutter rig or adding a bowsprit, and flying an asymmetrical Spinnaker.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay
Last edited by Jeff_H; 09-22-2018 at 12:21 PM.