Very Crazy Hobie 21SC Canvas Cabin Idea

Hey everyone, my first post regarding boat design here.

(Super condensed backstory) I've owned 4 cruising monohulls in the past. I live in Japan near Tokyo and have been looking into some ways I can get my "cruising boat" fix. Most things are just too expensive here, so after much research I ended up with a couple options that are attractive to me:

1) Build a Jarcat 5 and store it in my garage. I have a separate thread in the boat building forum regarding this.

2) While looking for sources for the Jarcat 5 mast and rigging I came across the Hobie 21SC. It seems people use the SC model as nearly a cruiser and I somewhat like it. Also, there is a local club here that has very reasonable boat storage prices and an active Hobie community.






(image from http://www.boatstogo.com/bimini-top-tent.asp)

When I look at the deck of a Hobie 21SC underway I start thinking that it would be neater if it had some sort of cabin. It'd be closer to a Jarcat 5 and I still don't fully want to let go of the idea of doing a project.

So my question is: Is it feasible to design and build a semi-permanent sturdy canvas tent on the "deck" of a Hobie 21SC?

I realize this raises quite a few design concerns; probably many that I haven't thought of:

1) It has to be somewhat aerodynamic (i'm thinking something like the canvas pilothouses on some larger boats)
2) The crew has to be able to escape in the event of a capsize
3) It has to be possible to walk from the bow to the stern
4) It can't add too much weight
5) It will affect sailing performance
6) The sails may have to be de-tuned in some manner to reduce capsize likelihood (This may already be the case in the SC model vs racing models)
7) Water will come up through the trampolines, what would happen if the bottom of the tent was waterproof? (had a canvas floor)
8) Could one section of the storage locker then be converted to house a portable marine toilet?

 

The quick, cheap and easy solution is to pitch a self-standing tent on the trampolin. All you have to do is secure the four corners so it doesn't fly off while you are sleeping in it.

 

I've actually done that Gonzo on my olde Hobie 16 , used the main halyard to hold the tent up and pushed our storage coolers and bags off the tramp to hold the slightly larger than the tramp tent floor off the tramp for even more room, worked great. Even sailed downwind with the tent up one time just because, door facing aft, tent inflated like a balloon, quite a sight running down Biscayne Bay

 

Forgive me for being a complete beginner with Google Sketchup, but I created this design. It somewhat evolved into a dodger with some storage space. The piece in front of the mast would be covered with canvas, but have a net on the inside for storage. The entire floor would be canvas and now the catamaran would actually keep the occupants/cargo dry. Another major concern is what would happen to the occupants in the event of a pitchpole/capsize. I'd really like to put a bimini over this, but I also want to ensure that the occupants can be dumped/freely excape. The base would clamp to the wings (which can already support the weight of passengers)

While doing lots of reading about the Hobie 21, or even Hobie Getaway, owners and why they purchased the boats many have expressed a desire to remain dry and they really do seem to be used as tiny family cruisers. I'm starting to think I may not be so crazy to suggest this afterall.

Suggestions? I was thinking maybe the whole thing should be able to fold or conveniently disassemble for trailering.




Here is a picture of passengers in a Getaway (for reference). It has less headroom below the mainsail:



Maybe something more like this for the Getaway since the main sail is fairly low when sheeted in:

 

One of my best friends did this with a reynolds 21. He and his wife cruised all over the So Cal coast and the channel islands. They replaced the tramp with plywood and mounted aluminum beach chairs for seating. They also had a 10 hp honda mounted on the aft cross beam. They mostly powered up wind and sailed reaching and running. Used igloo ice chests mounted to the deck for storage and a camp stove for cooking. One interesting story they told was a time cruising in the channels island when the wind and sea came up. To get some rest they sailed onto a very large kelp patty and stuck the dagger boards down into the kelp effectively anchoring their cat. What you are proposing is doable.
Good luck with your project.