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Birmingham square base plates

I know Tyler Wilson build on a Birmingham square base plate that is wider than the standard 2 meters.Are there any other hull builders using this wider base plate?

Asked by: John Dibble  | 8.42am, Monday 12 March

WW says:

Sheet steel comes in standard sizes of 2 and 2.5m. To reduce waste, many boat builders use 2m steel for the base plate and taper the hull sides down to this bottom width. This means that the width of the boat is wider at the gunwales than at the bottom, the difference being around 3 inches (75mm).
Tyler Wilson is one of the shell builders that prefer to follow the shape of the (now historic) carrying boats which have vertical hull sides. To avoid cutting 2.5m plate down to 2.1m, which apart from being costly in labour also produces a lot of scrap steel, they have a whole batch of plate rolled slightly wider by special order with the steel mill. They are unique in doing this, but not in building shells with square sides.

Rupert Smedley  | 1.43PM, Monday 12 March

The term "Birmingham Square" probably refers to the BCN day boats which were built with straight sides first in wood and then in iron. This made them easier to build and gives a large cargo capacity.
The long distance carrying boats were usually built with finer lines than the short haul BCN boats. The bottom 12 inches or so of the hull side tapers in from the vertical to the base plate, and the top part into the gunwale. Modern boats usually replicate the top bend only as the bottom detail is hidden by the water.
The problem with 'slab sided' boats is that many canal structures have tapered sides. This means that the bottom edge is more likely to scrape or get stuck, especially in tight locks which are narrower at the bottom than the top. Boat builders avoid this problem by building their boats about 2 inches narrower than the original cargo carrying boats. This is why it is the historic boats that are the first to get stuck when canal structures deteriorate and clearances get tight.

Rupert Smedley  | 3.00PM, Monday 12 March

Readers say:

Thanks for the replies.

John Dibble  | 7.53AM, Tuesday 13 March

Elton Moss Boatbuilders also use the Birmingham Square design on their 58ft Windsor range. It allows them to have a 4ft 6in wide bed as part of their standard spec.

Chris Robinson  | 2.26PM, Sunday 24 February

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