Scout Project

Here's a design proposal

I gather that you want to take an even number of adults (probably 2) and about half a dozen early teen boys down a big river, in a safe boat they build with your help. You want to sail, and you want to take the boat back up the river.

How about a Bolgeresque scow schooner, with a birdwatcher-style cabin and water ballast?

I envision a trivially simple plywood scow hull (the sort that my father called a cement trough), with straight, vertical sides and a flat bottom. 40 feet overall, about 32 feet on the waterline, 6 feet beam. If this turns out to be too large a boat, you could cut four (or two, or eight) foot increments out of the midsection with little effort. You could cut them out before you started building, that is! Once the hull is completed, adding or subtracting segments might not be worthwhile.

The ends would be left open, with decks just high enough above the waterline that the ends will be self-bailing.

The central 24 feet would be a birdwatcher cabin: fixed plexiglass windows extending the sides upward, with a roof which is open down the center, full length. The central slot can be left open for ventilation and sail handling, and closed with cloth or solid covers in rainstorms. The center slot will be kept narrow, so that if the boat gets knocked over on its side, it would float on its side and take no water until the water ballast righted it.

The cabin ends would be sealed off by watertight bulkheads for and aft, with washboards to allow access to the fore- and after-decks. Normally, everything would be done from inside the cabin, which would be low enough that the crew's head and shoulders protrude above the roof when standing. No danger of falling overboard.

Accommodations would be camping in the cabin. A section of the cabin could be curtained off for a portapottie or two. A bench could be set up for a campstove at the other end of the cabin. At night, the hatches could be closed and sleeping bags unrolled on the floor.

The 8 foot long foredeck could be used for handling lines when docking, anchoring and beaching. The 8 foot long afterdeck would be split to form a motor well for the modest sized outboard. Having the outboard back there keeps the gas and exhaust out of the cabin. The hull sides will have to extend high back here enough to help keep the kids aboard. Having the motor in a well means that it's possible to work around it, mount and dismount it, and so on, without leaning overboard. Either open deck could be used to store portapotties on hot days, when they aren't being used.

When the wind serves, you would fill the ballast tanks, put down leeboards and put up sail. When the wind is contrary, or just not enough to overcome the current (thinking of the return trip), you would pump out the ballast and start the motor. The boat would be quite light (and too tippy to sail), and so should be able to motor at around 6 or 7 knots with modest power. It would need a bit of fixed ballest to ensure that it would still go back upright if knocked down with the ballast tanks empty. Of course, with the ballast tanks full, you could motor sail.

I'd suggest something like a two or three masted sprit or dipping lug rig. That would have enough lines to give lots of kids something to do, and it would keep the masts short and the center of effort low. Ideally, you'd want the masts to be short and light enough that two or three of the kids could unstep them and lay them on the cabin top by hand.

Construction would match the shape: crude, simple and effective. Since the boat will have little use after this one trip, and you might end up abandoning it along the way if your schedule gets compromised somehow, cheapness is everything and longevity beyond that first summer isn't very important. Therefore, the boat would probably be built of ACX plywood and dimension lumber, and painted with latex house paint. This sort of boat isn't going to have any resale value, so it would be foolish to pour money into materials beyond the bare minimum needed to make it hang together for the trip.

The bad side of this is that the kids wouldn't learn much about traditional wooden boatbuilding, or dinghy racing. The good side is that they could reasonably hope to get the boat built in under a year, and without sending everyone into bankruptcy. A boat which is big enough to house eight to ten people is going to be an unsatisfactory race boat, unless it is quite expensive, so I'd recommend that if teaching them to race sailboats is one of your goals, you should plan for them to build some little sailing dinghies the following summer. Let your houseboat be a houseboat, and your sailing dinghy be a sailing dinghy.