Long Bottomed Wooden Boat Construction

[BEngo]

I have read that some at least of the early wooden canal narrow boats were long-bottomed- ie the bottom planking ran fore and aft. I expect there are few if any surviving remains, but can anyone explain how this form of construction worked please?

 

Was there still a keelson? Were the planks fastened to each other directly or where they fastened to frames across the bottom (floors?) ?

What sort of join was used if a full length plank was not available or damage needed to be repaired?

 

What might have been the advantages of this form of construction (apart from hydrodynamically better shaped boats were/are built with all the planking fore and aft)?

 

Thanks for any information.

 

N

[Derek R.]

Not being a boat builder I wouldn't know. But consider the application of longitudinally laid bottom planks against athwart.

 

The longitudinally built are more used in river and Sea going craft allowing more 'shape', either Carvel or Clinker built. There are generally more ribs to which they can be fixed.

 

For a flat bottomed canal boat the 'knees' are there to maintain strength between the sides and the bottoms, and wide bottom planks or boards would mean less wood to replace, and possibly with greater ease than if replacing a few long planks or boards.

 

It would appear that a desire for simplicity, ease of maintenance, combined with strength, would make athwart boards a common choice.

 

Or, it could be down to available timber at whatever price it was at time of build.

 

Or, It could be that a long thin boat without a 'shape' to the bottom would be longitudinally stronger with athwart board than with longitudinal planks.

 

I'm sure there are technical and economic reasons for choosing one over the other - so await the experts.

 

There - you can tell who is sitting at home and bored.

[carlt]

It is possible that this occurred but the only surviving examples that I can think of are the round bottomed icebreakers.

[Pluto]

Longitudinal bottom planking is quite common on river barges and boats, such as Thames sailing barges.The two photos here show a replica Ruhr coal barge being built at Mülheim around ten years ago. The construction is typical for such craft. Often, no keelson is used and the planks are sometimes held in place by dowels of some sort, together with the framing as shown.

 

[Laurence Hogg]

It was common practice on BCN day boats to have planking laid Longitudinal over the bottoms (conventional) in the hold if the boats were on traffic where the unloading was by grabs. Laid this way the grabs didnt pick up on the joints of the bottom boards. The boats working to Wolverhamppton and Birchills power stations had this feature and I have no doubt it was used elsewhere where grabs were in use.

Edited January 18, 2012 by Laurence Hogg

[BEngo]

Thank you all.

 

N

[koukouvagia]

This is a bit off topic, but some of the earliest wooden boats in Europe had longitudinal timbers and were built without knees or keelsons.

 

In 2000 a group of academics, naval architects and craftsmen succeeded in building a replica Minoan boat based on a design going back to the Greek Bronze Age, circa 1450 BC.

 

Cypress timbers were laid side by side and roped together to form a raft. The long edges of this raft were drawn up and attached to a large A-frame, where modern gunwales would be. The boat was made watertight by covering it with linen which was daubed with a mixture of resin and animal fat – an early form of blacking! The boat was then fitted with rowing benches for, IIRC, about 25 oarsmen and a large square sail. It crossed the Aegean from Crete to Athens as part of the 2000 Olympic Games celebrations.

 

If anyone is interested, the boat is stored in one of the Venetian shipsheds in Chania, Crete. Well worth a visit.

 

BTW there is nothing new under the sun. The Minoan sailors had a prototype pram hood to protect them from the weather.