Forums: The Deben 5-Tonner: Name New Topic Post Reply
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Posted: Jun 20th, 2010 at 00:50   |   Subject: Name
Good evening!

I am curious about the name and trying to learn more about it. Can you point me to where I can learn about the history of this/style of boat?

Also what about "Tonner" - I assume it has nothing to do with displacement?

Posted: Jun 20th, 2010 at 23:11   |   Subject: Name
Good evening to you!

The name is taken from the river Deben, where Whisstocks Boatyard was situated. If you look on our site under Holidays – Woodbridge, you can see a picture of the Deben at Woodbridge (about 9 miles from the sea). The white buildings on the left are the old tide mill and granary; then the building with the red roof is the old lofting shed (where the original Deben 4-tonner lines were lofted) and the high buildings with the grey roofs are the old building sheds.

The name Deben probably comes from Anglo-Saxon for "Deep One". Anglo Saxon King burials dating from the 7th Cent. are across the river (just off image to the right on the picture). A huge treasure was found there in a burial longboat in 1939 (look on British Museum - Sutton Hoo Treasure) and there are also Roman and pre-Roman Iron Age remains.

When my father had the 4-tonner designed by Wm. Blake, in the early 1930's he named the design "Deben". The Deben is reckoned to be one of the most beautiful rivers in the UK.

So -- on to "Tonner". Thames Tonnage was created by the Thames Yacht Club, and was designed for small vessels, such as yachts. It was originally used for calculating the port dues for yachts; the formula was also used in some early handicapping systems for yacht racing.

It is quite a good indicator of general yacht size and it became a common "shorthand" for describing yachts -- a four-tonner, a six-tonner and so on -- gave a reasonable indication of a yacht's sort of overall size. It was in common use up to about 1970 or so.

The actual formula is as follows:

Thames Tonnage = (length - beam) x beam x half beam / all divided by 94

Length is the length from the fore side of the stempost to the aft face of the sternpost (in feet).

Beam is the maximum beam in feet.

As you surmise, Thames Tonnage doesn't have a lot to do with displacement - though of course it does in a generalized sort of way. And it really isn't a bad way of describing a yacht -- better than overall length for example, which doesn't really give a very good idea of the useable volume of the boat.

Historically, tonnage was the tax on tuns (casks) of wine that held approximately 252 gallons of wine and weighed approximately 2,240 pounds. There has always been some confusion between tonnage (capacity) and displacement (or weight) of a vessel - I guess because tonnage (casks) which is a measure of the vessel's capacity and tonnage displacement, which is a measure of the vessel's weight were both based on a 2240 pound (long ton) unit.

Hope this helps! Thank you for such interesting questions.


Posted: Jun 22nd, 2010 at 01:29   |   Subject: Name
Thanks for the info! I do love history and learning all the neat little facts that come with it.

Funny thing, about 4 years ago I was researching some 1670 mead recipes and came across the word "tun". For the life of me I could not find a good reference for it and what it meant anywhere.. and here it pops up in your explanation for something "unrelated"! Another piece of the puzzle into place. :)

oh and I am sure to have more questions!(not sure if that is a threat LOL) But I am waiting for now as the ones that are popping up in my mind now, I think will be answered once more of the plans become available. :)

Posted: Jun 23rd, 2010 at 11:11   |   Subject: Name
Questions, comments, opinions and answers are always welcome! So ask away!