IIRC you can up the maximum in SH3 Commander.
I never have, because 1024 is plenty high enough for me when I'm in areas where I don't expect to run into any trouble. 128 is usually the highest I'll go when in potentially unfriendly waters.
And I don't even bother with more than 8 or maybe 16 coming in and out of port, with all the other ships around to be sighted I just keep dropping out of TC every few seconds anyway.