To build a small beach cat

[Rene Amyot]

Hi all. I live for part of the year on my sailboat, a Hunter 45CC in Mazatlan Mexico. We are moored in marina Mazatlan most of the time although we cruise the sea of Cortez and the Pacific coast of Mexico from time to time. Love sailing! My problem is cutting away from dock becomes a major issue for a few hours sail. To counter this I purchased a second hand poly sit -in kayak and modified it into a knock down outrigger sail boat. I built a thin plywood pontoon (glassed), a pair of outrigger arms , a combination mast step centerboard trunk, a kick up rudder and a Bermuda style rig. These components live mostly in the forward v-berth and are assembled when we return in season. It sails reasonable well in the esturey near our marina slip. This small success has emboldened me to think of building a slightly larger, knock down sailing cat with a pedal/prop aux.drive. Here is where I need real design advise concerning hull shape, mast position etc. I've drawn a preliminary plan and I'll post my drawings for constructive advise when I figure out how. I would appreciate help with regards to posting photos and drawings. Thanks

 

[upchurchmr]

Lots of us will be happy to comment.
Some will even be nice about it.

I hope you have a thick skin.
Can you post pictures of your first boat?

 

[JamesG123]

So you are intending this as a dingy or tender or runabout for your Hunter, or as a replacement for it?

 

[Rene Amyot]

Hardly a replacement for a 45' cruising liveaboard. Design length 8-10 ft. to be knock down for storage on "Babeeze" and for speedy fun sail only. I will post a picture of my existing kayak conversion and drawings of my proposed new project when I return to Mexico in mid October.

 

[JamesG123]

As you compose your posts, keep in mind that we can't read your mind. Sarcasm and snippy comments also will not induce constructive input either.

 

[Blueknarr]

Welcome to the fun.

I suggest taking a gander at the many sites which offer low to no cost plans. You might find one sufficiently similar to your idea that you can avoid a lot of engineering

Good luck

 

[Rene Amyot]

As you compose your posts, keep in mind that we can't read your mind. Sarcasm and snippy comments also will not induce constructive input either.

Sorry if I sounded snippy. Not intended. I thought my post specified slightly larger than the kayak and to be knocked down for storage. Sorry the misunderstanding. The kayak is only 7 or 8 ft. in length and the outrigger pontoon is about 5 ft. All the photos and a short sailing video are on other media that I can't access at this time. As to why I want to design and build myself, It's for the fun and to learn. Sitting in a marina with time on my hands is boring and I drink too much rum.

 

[BlueBell]

RA,

Welcome aboard!

Ah, a sense of humour, I like that.

Too bad you are limited by your knock-down clause.
How about a full size beach cat on a tow line off the stern of your live-aboard?
Tow it with on day trips or leave it on the hook while you're gone.
Storing it on board is a real limiter, no?
Is it really the only way?

 

[Rene Amyot]

RA,

Welcome aboard!

Ah, a sense of humour, I like that.

Too bad you are limited by your knock-down clause.
How about a full size beach cat on a tow line off the stern of your live-aboard?
Tow it with on day trips or leave it on the hook while you're gone.
Storing it on board is a real limiter, no?
Is it really the only way?

Towing is really not an option. We already have an elaborate arch with davits for our rib, 4 solar panels, gps antenna, satellite tv antenna, bracket for an outboard, and storage for the kayak on the stern. this reduces visibility astern and monitoring a towed small cat would be difficult. At the stern, on either side we have baskets made from 3/8" SS welded rod. They are roughly 12"W, 4-5'L and about 30"D. They are mounted outside of the rails and may be set up to carry a hull under each. This is getting long so I will post some tentative rough drawings showing my thoughts so far. I should mention the baskets normally store 4 jerry cans of diesel and 8 fenders. Have uploaded a pfd file on my original post with sketches. Sorry for the orientation.

 

[BlueBell]

Okay.
Not a lot of design complexity in a small cat.
Long and skinny hulls, lightweight construction,
quality components, well thought out.
So, hulls in the V birth, mast on deck?

A pedalling station is going to be interesting.
60 tooth chain to 10 tooth, 1:1 right-angle-drive to
5/16" spring stainless-steel 6' flex shaft to an unsupported
16" - 18" adjustable pitch R/C airplane 2-bladed prop.
The prop will self-stabilize, unsupported... crazy but true.

 

[Doug Lord]

Towing is really not an option. We already have an elaborate arch with davits for our rib, 4 solar panels, gps antenna, satellite tv antenna, bracket for an outboard, and storage for the kayak on the stern. this reduces visibility astern and monitoring a towed small cat would be difficult. At the stern, on either side we have baskets made from 3/8" SS welded rod. They are roughly 12"W, 4-5'L and about 30"D. They are mounted outside of the rails and may be set up to carry a hull under each. This is getting long so I will post some tentative rough drawings showing my thoughts so far. I should mention the baskets normally store 4 jerry cans of diesel and 8 fenders. Have uploaded a pfd file on my original post with sketches. Sorry for the orientation.

=========
Nice sketches......I like the pivoting seat system-how many people at one time do you envision using the boat? I'm not sold on the pedal system since you should be able to sail most of the time-when you can't maybe you could row or paddle? Possibly use a single centerboard and a single rudder to simplify stowage and set up.
Good Luck!

 

[Rene Amyot]

Okay.
Not a lot of design complexity in a small cat.
Long and skinny hulls, lightweight construction,
quality components, well thought out.
So, hulls in the V birth, mast on deck?

A pedalling station is going to be interesting.
60 tooth chain to 10 tooth, 1:1 right-angle-drive to
5/16" spring stainless-steel 6' flex shaft to an unsupported
16" - 18" adjustable pitch R/C airplane 2-bladed prop.
The prop will self-stabilize, unsupported... crazy but true.

The hulls will be mounted externally one on either side of the stern, under and supported by the SS baskets for lack of a better term. They will be marginally longer than the baskets by 3' or so but should be no problem. These (baskets) are constructed from 3/8" welded SS rod and hold 4 -5 gal. jerry cans of diesel and 8 medium size fenders. Approx. 12"W 30"D and 5' L. The pedal station is a standard inverted bicycle frame with rear forks removed and a welded hinged attachment to the fwd SS tube cross member. The lower sprocket turns a 90 deg. bearing mounted set of gears which in turn are rigidly attached to a 3/8" solid steel shaft, yet to be cut to length. this assembly is supported by adjustable tubes and a central bearing. this enables the propeller shaft to be raised above the water level when not in use. The support tubes form a triangular shape between the two hulls. The prop is only 2 bladed, from an electric trolling motor . I have constructed most of this already and it seems to work very well. The mast for my kayak sailer is 2 pce. It the rudder, center board, sails and all the spars reside in the v berth. The part of this project that I have little experience with is an efficient and speedy hull shape ( I hate to say planning hulls) their length, buoyancy and distance apart. Any critics of my proposed hull design will be helpful.

 

[Rene Amyot]

=========
Nice sketches......I like the pivoting seat system-how many people at one time do you envision using the boat? I'm not sold on the pedal system since you should be able to sail most of the time-when you can't maybe you could row or paddle? Possibly use a single centerboard and a single rudder to simplify stowage and set up.
Good Luck!

The rudders are doubled but the kick -up center board will be slightly off center (to allow for the propeller shaft) but centered between the hulls. The point of the pedal drive is to allow my wife or myself to exercise with the mast unstepped. Also when sailing in this narrow estuary with a tidal current tacking can be terrible. Very handy for coming off a lee shore. As to paddleing, my present kayak outrigger has the pontoon on the right and I am right handed. I am continually hitting the outrigger with the paddle. Very awkward! This is designed as a one person boat although possibly 2