Paqurus

[duluthboats]

Tad,

Why is it that things that fascinate me have so little marketing potential? A 70’ boat is not in my future, 50’ maybe. I can see 3 modules, A, B, C, which combined will make 2 boats. A, (the bow) and C, (the tractor) together would make a nice fishing/pleasure boat. When B, (the cabin) is added, you have a nice protected water, cruiser. On the hard, A and C would have one trailer and B would have its own. A 50 footer could have modules 12’, 25’, 12’, and a beam of 8.5’, that would be easy for a DIY’er to build in his garage. No special tow vehicle required. I’ve been humming this tune for a week now and it won’t go away.

Gary

[gonzo]

How would you assemble them?

[Portager]

In Tad’s earlier post he indicated that the sections would be launched individually and assembled in the water. I like this approach, but I think the joint design warrants additional creative thought.

It is kind of like an over grown nesting dinghy.

Gary, I like you interchangeable sections idea, it adds interesting possibilities.

To simplify mating and reliability I think the goal should be to minimize the interconnection between the sections such as drive shafts, fuel lines, electrical connections, … I don’t think it would be possible to eliminate all the interconnects, but the fewer the better.

Regards;
Mike Schooley

[duluthboats]

I can see using 3 hand crank winches two pull the modules together. You would need 4 or 5 pins for alignment. Once joined there could be a bunch of over center hooks to lock the joint.

If most of the utilities were in the tractor module you could get away with a few quick disconnects.

Gary

[Portager]

So, your approach would just have two sections? The aft “tractor” section would have the engine, drive train, fuel, pluming, … and the interchangeable forward sections would be living space? That would eliminate many of the bothersome interconnects such as drive shaft, … This sounds like a good approach to me. I think the joint would be a little forward of the center to allow the aft section to accommodate the majority of the systems.

One potential problem is if you center the expendable masses (fuel, water, …) around the combined CG, then the trim of the aft section will be dependent on the level of the expendables. Differences in trim will make joining harder but I think the joining system could be designed to accommodate that.

You could probably get by with an electrical connection and a cord that you connect after the mechanical mating. You could do the same with water, but I would have separate discharges and holding tanks to eliminate sewer interconnects.

I’m thinking this could be an interesting collaborative design effort.

Regards;
Mike Schooley

[Tad]

Gary a man of vision!

The permutations seem endless, my original concept involved two sections, a forward empty fairing with an aft section housing engine, tanks, pilothouse, etc. The split would be about 60/40. That was to be a 55' by 8' dory that was to make the most of a 10 HP diesel.

The main problem with several operational modes is that the hull form needs to be tuned to the various speed/length ratios. I could see the bow section of Pagurus being a useful flat-water outboard skiff. In the three piece scenario described by Gary the ends would need some deadrise. But with the addition of the midship section S/L would probably drop and the stern would no longer be a good shape for the speed.

I remember some local ferries that were lengthened by adding a midship section about 85', speed increased slightly with the same power.

I was actually thinking of launching Pagurus complete and dumping the ends overboard while the whole works is afloat. It seems trouble and damage would be minimized that way. I had some thoughts about using ballast tanks to ease alignment for latching the bits together, that's probably too complex. Reloading would be the hard part, more work needs to be done on that. But I believe the reason for doing this would be to have shorter and easier to launch/handle bits. They could also be built in a smaller space.

I believe Bolger's latch method on the folding schooners involves hinges up high above the sheer, and then pin fastenings in the chine down low. Hinges are only workable if you are using the "switchblade" configuration.

I still think the idea has merit for a minimum cruiser made up of a 10-12' long tent-trailer type living section that could be towed behind a small car. This box could be lengthened with two empty ends, also 10' long each, one could travel on top of the car, the other on top of the tent-trailer. The sections would be built of plywood, could all store in a small garage. The ends could be sailing dinghies for the kids to race leaving the living section aground on a mudflat.

Take care, Tad.

[gonzo]

How about using large conical pins? They would be easier to start and would tighten as they get closed.

[duluthboats]

Now I can sleep again, as it seems reality has dulled my vision. Thanks Tad, it’s the only way I ever learn, from my mistakes.

Gary

[Tad]

Gary;

I certainly didn't mean that it could not or should not be done, only that you've added several more variables to the equation.

It will mean juggling weight and power/speed of ABC against weight and power/speed of AC. Then, if ultimate efficiency of ABC is not the ultimate criteria, you can compromise her shape in the interest of a decent hull for AC. Yes?

Performance of AC will be limited by the power available, would it make sense to put triple 250 HP outboards on ABC? Not to me, but others may think it a great idea. I would be much more interested in what could be achieved with twin 40's.


All the best, Tad.

[duluthboats]

It wasn’t your post that discouraged me. It prompted me to put some things on paper. I can make two boats out of three parts, but one is going to be real ugly. Twin 40’s? I was thinking of one 50. I will continue to play with it and have learned much from the exercise.

Gary

[Willallison]

My sister owns a 23 foot thing that we rather disparagingly refer to as the 'party barge'. I say thing because it blurs the line between pop-top caravan and trailerable cruiser. In reality it is a very good, smooth water short-term liveaboard. Being rectangular, there is a lot more room than one would expect - it comforably sleeps 6, has a separate wc / shower cubicle, enormous galley and an a very comfortable outside front cockpit. An 8hp 4-stroke o/b means that it's no rocketship, but to want to go much faster would be to miss the point.
Anyway, I was thinking that a variation on the theme might work well for the ABC boat. The central, pop-top living space, with two cockpit ends. The low profile of the cabin module when folded down would allow A & C to sit on top and still be low enough to tow about.
Pics aren't very good, but you get the idea....

[yipster]

that "thing" is making sense Will!

another variation of separating boats was named the "disco volante" seen in a 007 james bond film