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Sunday, January 31, 2010

RedPeopleEverywhere

Enough room for storage, enough bunks indoors, enough room for cooking. Still, I'm uncomfortable with a big opening in the deck just forward of the mainbeam. But I guess enough carbon will make it stiff enough. The head might even have enough room for a reservoir, for inshore use, just to make it legal.

Saturday, January 30, 2010

DesignProgress 3001010

Aft bunk is convertible, while unused it turns into a chart map/navigation station in one of the hulls, while the other one will turn into a galley, or a mix of those functions. Under the foredeck there will be a shitter and possible sitting shower in one of the hulls, while the other one will house another bunk, sleeping 5 crew inside currently. The big skipper bunks are almost double size. Storage under the crew bunks, fore triangle, under cockpit. Crew bunks and loo accesible via a big round hatch. Galley functions up next.

Friday, January 29, 2010

DesignProgress 2901010

I was never happy with those top hatches that slide to open. I'd rather have a swing door, even if it is small, at least it can be truly watertight. Moved the interior partitions and tried the Farrier style rudder setup -kickup daggerboard rudder. By design those entry hatches/doors do not stay open, so water/splash getting in will be minimum. New cockpit/transom layout made me lower the rear beam to about 95cm above WL, probably enough clearance for crusing. Interior will be modular, will be my next focus.



Sunday, January 24, 2010

KickUpRudder

The first version lacked the ability to steer the cat in shallow waters. That is something I forgot about. I abandoned the tapered rudder planform in order to have as much usable area for steering in shallow water, moved the rear beam forward and tweaked the system to enable steering with the rudders partially up. A 35 degree rotation around the upper pivot will allow a 35cm rudder draft, good enough for beaching. The system needs tweaking for sure but I hope I can make it work without the need of casings, boxes, cassetes etc.

Saturday, January 23, 2010

KickUpBusiness

I've been scratching my head for a while trying to come up with a kick up design for the rudders. There are some interesting variables in the equation. First of all my rear beam is very close to the transom, basically it is the transom as the rear beam is fixed in a double bulkhead configuration, so I tried to push it aft in order to be able to use the space inside more efficiently. Since the rear beam is at the transom, the hulls being low and the beam connection to the hull is a high bend, there is no room for a cockpit facing tiller, that means I have to invert the tiller config. A regular beach cat kick up system uses a pivoting rudders in a casing, depending on the height and configuration of the transom that foil usually gets pretty tall, which I don't want. I will only be able to make moulds on a cnc machine up to 134cm tall. The usual beach cat kickup system has slop nomatter what you do to it. I really don't want to be fairing a 170cm rudder or remake one in case it gets smashed. I'd rather have a shorter rudder, less carbon, less material, easier to make, cheaper. I wanted to eliminate slop if possible so I came up with this system. The tall post can be made by laminating carbon over wood, doesn't need to be faired to perfection, requires less finishing. If the foil gets damaged I'll remove it from the post and make another one, stick the post into it, glue it and that's it. Cheaper. I wanted all the parts in the kick up system to be very simple, easier to improvise all over the world if I need to. Brackets, bearing bolts and some levers. If the rudder hits something the lower joint will pop a calibrated bolt, breake it , swing and rotate around the upper pivot, clear out of the water, and clear of the tiller crossbar, that means the other rudder will still give control. Asess damage, swing it back to position, refit bolt and move on. The system parts are pretty heavy duty and obviously not not very light if engineered by hearsay. Apart from the weight, the odd looks, I'm pretty comfident it should work quite well and be very robust. No casting or case that can brake, I would say slop free, and easy to maintain, just check slop in bearings, if any, lube it, check calibrated breakable bolt and that's about it. I guess...


Tuesday, January 5, 2010

TheScaleModel

In a few months I will be able to make a 1/10 scale model of the boat. The model will hopefully be used to determine the behaviour of the hulls. This is my first attempt so it should be interesting. The hulls will be carved on a 3 axis CNC machine. The scale model testing should provide info for the further development of the boat dynamics, weight distribution, wake patterns, max beam etc. I hope the testing will output some solid information, however since this is all new to me I'm not expecting too much out of it.