Cat rigging?

[Marc78]

I need a little help on a design I am adapting for my personal wishes. I changed an excisting realy classic design to create a large cockpit for day sailing. However because of my design, the original location for the mast now goes straight down through the space I kind of wanted the toilet to be... One of the solutions I'm thinking about is to put the mast more foreward and deleting the jib while keeping the Centre of Effort in the same place. Since I have no experience or whatsoever with cat rigs, does anyone have any pro's or con's why I should or absolutely should not go for this solution?

[Gary Baigent]

There should be no problem - if the CoE remains in the same, or close to the original position with headsail/main rig but .... your rudder must be a good hydrodynamic shape and maybe a little larger as cat rigged boats are heavier on the helm; you want the boat to bear away in stronger, running/broad reaching conditions, and not round up because your rudder stalls out. Another point: shifting the mast forward means more weight there - check out the volume and shape of the hull's underwater forward sections - you need buoyancy there to counter rig weight, otherwise the bow will depress and you'll be on your ear again.

[alan white]

Cat rigs have plusses and minuses.
When you set up a cat rig, the mainsail becomes the sole reefing sail, meaning if you have a single set of reefing points, it's wise to set up a second set.
As long as you do your homework and find the correct CE, the boat should sail the same.
The real issue will be staying the rig. The staying base is quite narrow both athwartship and for and aft. 10 degrees minimum is recommended, meaning you might be up against adding a short bow sprit and possibly blocking out the chainplates (if it's at all possible).
i'd opt for a deck-stepped mast and a more aft location. I'd keep the jib (or a new jib) and fit a beam across the opening to bridge where the toilet goes, with two posts to the sides.

Alan

[Gary Baigent]

A freestanding mast rids you of the narrow shroud and forestay problems - otherwise you have to set outriggers a la IMOCA designs plus bowsprit.

[alan white]

One thing is for sure---- it's expensive to go with a free-standing mast and expensive to keep the old one and stay it correctly for a cat rig.
All for a toilet?
If you can possibly support a shortened mast on a hinged tabernacle using a beam and two posts, that would be the absolute cheapest and no doubt best solution of all. The only expense is a tabernacle fitted to the base of the shortened mast and the aforementioned framing members that allow the toilet space to be on center.
Obviously, from here it's impossible to know why the toilet couldn't be located to one side of the original keel-stepped mast or post.


Alan

[Marc78]

I didn't think of the weight issue yet, thanks for the tip. Reefing shouldn't be a big problem, since it is gonna be a daysailer for the small lakes and only realy when the sun is out. Also an option in this is, to design the sail in such a way that reefing doesn't realy change the CoE. I am planning if I choose for a cat rig, to do so with a boom istead of a wishbone.

I also figured to put the toilet on one side of the mast, but since the space available between keel and top of cabin is around 4' this is not realy an option. Since the space is not realy generous, I defenitly need something like a hatch to enter the cabin.

Also an option is to shift the original mast a few feet forward and also move the keel a little forward.