Trying to design my own cat.

99% sure I will get my own design built by boatbuilders with a good reputation.
I would only buy one if it really appeals to me as much as my own design.
For now, I am thinking of buying a cheap used beachcat, like a Hobie. I would sell it when I leave the country.

 

That seems sensible, Sadly not many of us are - hence this forum - for dissatisfied sailors in some form or other - - - seeking the attainable and un-attainable...

 

Here is the final design for my....not too offshore...beachcat cruiser. I was inspired by Chris Ostlind's 21' compact cruiser.
If it is not proven to be a death trap (critcism welcome), then I will definitely work with a NA to work out the details and get this thing built.
Goodbye to big boats.

Specs:

* not demountable

* 20 ft LWL

* 10 ft BWL

* 0.85 ft draft (not including rudders)

* 900 lbs empty

* 2240 lbs fully loaded (6 average adults with camping gear)

* 240 ft2 sail area

* outboard mounted boards when sailing lightweight, and no boards or daggers when fully loaded

* slide-up rudders or fixed, depending on final performance prediction

* all-weather canvas dodger (spans entire beam of boat and covers the 2 forward-most seats, at shoulder height for visability)

* canvas covers for cabin cockpits (overlapping zips for good seal. No solid door. Canvas just rolls out of the way)

* large tent (used when anchored or moored and covers the entire deck)

* bucket and bio-degradable bags (classy toilet system...no fuss no mess)

* carefully positioned cabin rooves for unobstructed ocean view, and they provide a useful workbench/cooktop

* inflatable rollers for hauling boat up beach

* small, light mast can be raised easily by one person

* lazy, social atmosphere

* sleeping bags on mattresses on trampolines, to provide a cosy feeling, while still feeling exposed to the ocean (something we all love on a nice day)

* no bridgedeck slamming, due to the chamfers and soft bridgedeck

* can be helmed from many different positions (using tiller extension)

* large gap between deck and sails allows panaramic views, with only slight reduction in performance

* all major metal structures will have a wooden or 'earthy' appearance to get rid of the cold, industrial feeling that shiney metal can create. Wood looks good with light coloured fabrics to make you feel snug. Lots of cushions everywhere too. Maybe a couple of teddy bears?.....mmmm....maybe not


Any criticism, performance estimations, or advice is always welcome.



THE LAZY, HAPPY SOCIAL BOAT
(haven't thought of a name for it yet)

 

Go for it lad, but consider the John Hitch rig (2 x genoas) - one to each bow, and no main - nothing to knock people out or kill them as happened recently off Frazer Is., - Queensalnd,..... sadly....

 

i cant read fbm files and when i go to windows search i get bombarded with more **** to buy

cant you post your dwg as pdf?

thnx

 

i would like to see what is going on in the hulls / cabins

otherwise it looks like it will certainly give you the fun platform you are hoping for

 

Hi Masalai,
Man you really like that rig don't you
I've read that it doesn't perform very well on any point of sailing other than running, and that it was originally intended for a specialised downwind trip. That doesn't sound very encouraging to me.

I have been thinking though about getting rid of the boom. Cats sail fairly close-hauled most of the time, but I know that it would reduce performance downwind if I have no boom (sail is too baggy). I can experiment with that without having to change the whole rig. Having no boom creates a 'softer' appearance and a safer feeling, especially with kids onboard, so I'll do it if it's not too slow.

Manie,
I haven't shown much detail inside the cabins even in the fbm file. When I get more time I will draw a few more details and post them.
The cabins are absolutely minimal, with only 3 feet headroom. To use the toilet you must sit on a sliding seat and slide into the cabin by holding your body almost in the 'crash-landing' position....or if you want to read a book or something, you can use the flip-up back support and slide into the cabin like you're on a dentist chair.
Both positions are comfortable. I tried it at home

 

All cats should have FLAT cut sails - no bags as mono's need... I like that rig cause I am lazy.... It can be balanced by a second pair of "genoas" rolled on the midship stays - you use the leeward set of sails... midships forard a blade on hanks also helps and doubles as storm jib and can be on a self tacker setup....

 

designing own cat

Richard, since you are after a small cruiser, why bother making it semi open deck cat? What you have is neither one thing nor the other. Why not put a decent cuddy across the boat? - it would be less fuss to build and be aerodynamically cleaner. That area forward of the mast looks solid to me but maybe it is lumite trampoline, either way it looks too fussy and draggy (there is no reason a cruising boat should not be streamlined) for better performance and aesthetics, and also, IMO, you don't want a solid area up there, be it solid wing or dense trampoline material. As the boat pitches (and your double ended design is going to do that) air and waves are going to be trapped there. Why not have open fishing net trampoline forward so those two elements can pass through. Also it is safer if you ever lift a hull, you don't want the wind to get underneath or you will end up doing a sky. then acutely angled horizon, then blue sea and lots of bubbles.
I remember doing a sail test on Bernard Rhodes little 20 foot cat cruiser and it was a good little boat except the wing deck was too low and pounded and forward of the mast was also mostly solid, and that pounded too. Bernie had a very neat rotating mast rig for the boat that in profile was similar to yours. Stick with that setup, large main, small headsails.

 

Hi Gary, thanks for your comments.

The bridgedeck is all tramps forward and aft. I was hoping this would eliminate pounding.

The boat has almost no rocker at all, to help avoid pitching and produce a little more speed, but it will be at the expense of tacking.

The bridgedeck looks 'fussy' because I have drawn the tramps very saggy. This is to provide a seat that allows a person to shift his bum to correct his centre of gravity when the boat is healing slightly. Do you think it is better to have tight tramps for aerodynamics? If it makes a big difference, then I will tighten them.

I didn't think of the effects of the tramps acting like sails when the boat is healing. I want to avoid flying a hull, because righting the boat would be a nightmare.

Exactly right. This is my intention. It would be more accurate to call it a 'summer holiday adventurer' rather than a true cruiser. I have no intention of sleeping on it (I hate sleeping on boats), although you could squeeze a couple of berths in the hulls if you wanted to.

I don't want a bridgedeck cuddy, because I want the boat to feel more like a Hobie than a big cat. I don't like the effect that a cuddy has on the view, and if I can pick the weather most times, people won't be sitting inside the cabins anyway. The cabins are there for a toilet and to act as table tops, and ofcourse for storage.

It is important to me that the boat can carry 6 adults. So the boat is small and very heavy. Do you think this will be a problem in say, a 1.5 or 2 ft chop? I'm not too concerned about speed, but I am concerned about safety.

Cheers

 

As for sunburn, or exposure to cold weather, there are ways to protect from that, so my main focus is on handling and performance.

 

small heavy cruising Hobie type cat?

Hi Richard
You don't want peoples' derrières dragging through waves because of floppy tramps, even in summer, IMO tramps should be tight. But the dense Lumite type trampolines are not a good thing forward of the mast, very comfortable, but again IMO, dangerous, because of the wind turning effect, better an open mesh. Actually it will be only in benign conditions that you will have passengers up there anyway. The little rocker should not be too much of a tacking problem but a slightly wider stern will help counter pitching.

 

Here's my final design. It's now 22 feet long and 10 feet wide. I'll leave the fine-tuning to a NA.
As always, any comments are welcome. I may replace the forward tramp with netting. It will be a wet boat, but I can live with that, as long as it can get me from a LA beach to Catalina Island.
In rough chop the 'cockpits' will be sealed with canvas which can be unzipped and rolled out of the way.
The boat is normally helmed from the aft seats...not the cockpits.

 

Looks sweet and neat, nice one Richard...

 

Thanks Masalai. It'll look better when the forward seats are flipped down when they are not needed. However, the boat won't sit level unless it is fully loaded with 4 adults forward and 2 adults aft.