well, good canon answers? Not that aren't GT derived... Whihc makes their canonicity questionable.
However... one can take the TCS numbers, and figure out a similar set for shipping at J1 (assume that price point based upon standard designs) if the system has potential trade parters at J1; figure at J2 if minimum distance is J2.
as a SWAG, and In the absence of GT:FT, and the absence of other support materials (like TCS), I'd figure Cr10 per head for a merchant shipping maintenance budget per year... Using 1/4 Type R, 1/4 Type A2, 1/4 Type A (assuming J1 routes exist), and 1/8th each J1 and J2 barges at 1000Td. So, thats KCr10 per head for shipping fleet. This, of course, represents the government owned liners...
for Rich worlds, double this number. For Poor, halve it. Industrial doubles, NI halves. TL below 8 halves; below 6 halves again. Double it for an A port, halve it for D/E ports, and quarter it for X ports.
Apply Cr1 per head for the mainworld and Cr10 per head for the subordinate worlds for in-system shipping maintenance, again KCr1 or 10 per head for new purchase costs, for an in-system fleet of merchants. Double for Rich, Industrial, A,B,G ports, halve for Poor, NI, D/E; quarter for X/Y.
Why that figure? Cr10 per head for maintenance costs?
Well, it's a nearly invisible amount of tax, and maintenance costs are the big limit. Bonds or other major capital expenses probably pay the initial and replacement costs, at least when not replaced by profit. I figure the Merchant Marine Support Tax is probably around Cr26 per head per year per person... much of which is shipping, etc...... And those ships probably are kept in service til they are no longer repairable!
