New Sidewheeler Building

[fredrosse]

Building a flat bottom steam sidewheeler, the project has gotten underway in earnest this month, the hull is very similar to a conventional "Sharpie". Six sheets of Hydrotek Meranti marine plywood, complying to British Standard BS1088, 12mm sides, 15mm bottom have been recieved, and glued up into 20 foot lengths using butt blocks with West system epoxy.

Framing is heavy, and fairly conventional, using Douglas Fir lumber, spaced 16 inches on centers. The frames are built up with polyurethane glue and coated screws. The plan is to glue the sides and bottom to the frames with thickened epoxy, and to cover the hull exterior with 9 oz bi-axial fiberglass cloth set with epoxy.

A few open items with respect to this construction:

Should boat nails or screws be used to attach the plywood to the frames? Or should I just use temporary screws, and let the epoxy do all the holding?

Should I paint the interior of the hull with epoxy, followed by a UV resistant polyurethane, or should I just polyurethane the interior without epoxy? I want to keep the natural wood visible on the interior, in order to be able to detect possible water intrusion.

The exterior of the hull will be painted a conventional color above the waterline, and some have recommended that the bottom receive a coating of epoxy with powdered graphite to better endure groundings and abrasion. Do any of the group have experience with this?

Thanks in advance for information.

[alan white]

Just a question about coated screws. I have used ceramic coated screws for exterior building applications and often wondered if they would be useful aboard a boat. Have you heard of their use aboard boats before?

[ancient kayaker]

Originally Posted by fredrosse

... Should boat nails or screws be used to attach the plywood to the frames? Or should I just use temporary screws, and let the epoxy do all the holding?

...

The following is my opinion and I admit that I have read dissenting opinions in the forum.

The epoxy will do the majority of the holding even in the presence screws. However, a concentrated load can force open a glued joint, usually with a split in one of the two wood members being joined. Once the split has started the stress concentration at the end of the split may cause the split to spread.

This is of most concern for an external seam below the waterline. In such cases my practice is to use screws to reinforce the glue. Overall the glue is far stronger than the sum of all the screws, but the screws can act as a rip-stop. The screws are also great for clamping while the glue is setting.

Above the waterline I don't usually bother, especially if the screws will be visible, except for heavily stressed members such as mast steps, rudder mounts, daggerboard trunks and suchlike.

[dskira]

Originally Posted by alan white

Just a question about coated screws. I have used ceramic coated screws for exterior building applications and often wondered if they would be useful aboard a boat. Have you heard of their use aboard boats before?

Alan, I tried, and after months on a saline solution with vinegar, nothin realy bad happened. But I don't know, I don't dare to go that path.

Daniel

[tinhorn]

I'm a fiberglass guy, so I have no opinion on nails or screws, but please show off your project. There aren't too many of us paddlewheelers; most of these guys are all caught up with the passing fancy of these newfangled propellors.

[fredrosse]

Rushed to get this steamer into the water for the last steamboat meet of the season, 10 Oct 2010. Much fitting out to be done over the winter, fortunately I have a heated boatbuilding workshop. Full description of the sidewheeler build can be found at >>> the steamboatingforum.net <<< inder technical, non engines and boilers, plywood sidewheeler.

[ancient kayaker]

Absolutely wonderful! Makes me want to get back to my steam canoe project this winter.

[tinhorn]

Man, that's awesome!

[Boston]

http://www.thesteamboatingforum.net/...t=349&start=10

definitely worth checking out folks

Ok so thats not a monotube boiler, the vent pipes coming out the top? is that where the exhaust gasses flow out of and is there going to be a stack coming off the top of that thing ?

[BATAAN]

Originally Posted by fredrosse

Building a flat bottom steam sidewheeler, the project has gotten underway in earnest this month, the hull is very similar to a conventional "Sharpie". Six sheets of Hydrotek Meranti marine plywood, complying to British Standard BS1088, 12mm sides, 15mm bottom have been recieved, and glued up into 20 foot lengths using butt blocks with West system epoxy.

Framing is heavy, and fairly conventional, using Douglas Fir lumber, spaced 16 inches on centers. The frames are built up with polyurethane glue and coated screws. The plan is to glue the sides and bottom to the frames with thickened epoxy, and to cover the hull exterior with 9 oz bi-axial fiberglass cloth set with epoxy.

A few open items with respect to this construction:

Should boat nails or screws be used to attach the plywood to the frames? Or should I just use temporary screws, and let the epoxy do all the holding?

Should I paint the interior of the hull with epoxy, followed by a UV resistant polyurethane, or should I just polyurethane the interior without epoxy? I want to keep the natural wood visible on the interior, in order to be able to detect possible water intrusion.

The exterior of the hull will be painted a conventional color above the waterline, and some have recommended that the bottom receive a coating of epoxy with powdered graphite to better endure groundings and abrasion. Do any of the group have experience with this?

Thanks in advance for information.

An opinion. Use bronze ringshank nails, no steel even if coated with gold. Thoroughly epoxy every surface of every piece of wood in the boat. Paint inside with clear PU over the epoxy if you don't like paint. Outside use Awlgrip paint. On the bottom put a couple layers of cloth and epoxy for chafe resistance.