Originally Posted by
Lieste
1502 BM isn't consistent with something smaller than a 42 gun establishment ship though... but is consistent with something of the general form of a large heavy frigate. As is a 30 gun gundeck.
It is also reasonable that the 'chartered tonnage' - what is available for cargo be lower than the calculated tonnage, (which is an 'average' used as a rule of thumb for taxation of merchant shipping in general service, and for rough comparison of ships and other vessels beyond merely their "number of guns", which is a flexible and mutable characteristic - often set by custom and fashion, rather than by what will 'carry'), if this is of a finer 'frigate form' than a fat bellied merchant.
EIC ships were sometimes bought/leased as naval vessels when need was high and time short, as they were pseudo military vessels (even if armed en-flute), with a desirability for a balance of cargo, crew and crew stores favouring profit (but not eliminating self defence) in their EIC standard fit.