Friday, December 19, 2003

Lasts, why they can't be reliably calculated In the early 17th Century, Dutch ships have sizes in terms of "lasts". Dimensions are very rare. I do not have any archival documents that list dimensions. Lasts are a load-carrying measure. I persist in trying to calculate lasts for Dutch ships, because there is no other way to estimate dimensions. When I want to draw ships, they must have some dimensions. The reason why estimating size from lasts can't be done with any accuracy, is that they seem to have been largely estimated. Unlike English tons and tonnage, there was not a formula that you can apply. Well, there is a formula, but the constant fluctuates. The formula is: Lasts = Length x Beam x Hold / K The length is the length from stem to sternpost, in Amsterdam feet. The beam is that measured inside the planking. The hold (depth in hold) is measured at the side of the ship. I have heard it described as being at the widest part. I will include a diagram. The tricky part is "K". Lasts generally seem to be rounded off. The K is adjusted to make the amount end in a zero, generally. For example, the Brederode had the following dimensions: Length: 144 feet (Amsterdam) (132 Maas feet) Beam: 35 feet (Amsterdam) (32 Maas feet) Hold: 14 feet-8 inches (Amsterdam) (13-1/2 Maas feet) The product of Length x Beam x Hold = 74225.45 cubic feet The lasts are given as 300, so the K needed is calculated: K = 74225.45 / 300 = 247.42 This is a quite large K. I usually use a K of 217. Another example is the Gorcum, which we believe was 150 lasts. Length: 116 feet (Amsterdam) (106 Maas feet) Beam: 27 feet (Amsterdam) (25 Maas feet) Hold: 11 feet (Amsterdam) (9.5 Maas feet) 150 = 116 x 27 x 11 / K K = 116 x 27 x 11 / 150 = 229.68 As you can see, this is not an exact calculation. A feature of my examples is that they are ships that have published dimensions that would appear to be Amsterdam feet, but actually Maas feet. Today, I saw the Brederode described as having dimensions of 132 x 32 x 13-1/2 feet, which everyone had assumed were Amsterdam feet. The crazy thing is that information has long been available which clearly shows these dimensions as been "Maes voeten" (Maas feet). A Maas foot is the same as a Rhineland foot, and is approximately 12/11 x 283mm, or about 308.7mm. I have a published source and two archival sources that confirm this. Experts, including Prof. Jan Glete and Ab Hoving, have known this for a long time. I only learned it in early 2003, when I received the Rotterdam Admiralty document dated 26 February 1652.

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