A ship measured at 170 lasts is probably something with dimensions similar to 116ft x 27ft x 11ft. If we use a factor of about 200, then lasts = length x beam x depth computes to 170 lasts = 116ft x 27ft x 11ft / 202.7. In reality, 200 is a good factor, and we just need to round generously.
The Dutch seemed to like certain ship lengths, such as 112ft, 116ft, 118ft, 120ft, 125ft, 128ft, 130ft, 132ft, and so on.
For example, the Zeeland ship West Cappelle (which we know was 112ft long) was measured at 150 lasts. That would mean dimensions something like 112ft x 26ft x 10.5ft, if we still round generously.
This is my system for estimating ship dimensions, where we only know lasts, or lasts and a length.
