Cut the crap, Capn!
"But..." you say, "...sip, schmips, gulps, cut the crap, Capn, and tell us how much really is in a tot?". Fair enough, for although I know you enjoy my digressions, you also like simple, monkey-ready factoids.
A "tot" is one-half of an Imperial Gill. What's that? You don't know what a "gill" is? Fine. A gill is 5 Imperial ounces, thus a "tot" is 2-1/2 Imperial ounces. What's that? You don't know what an "Imperial" ounce is? Geez, already!
OK, let's do this in English, er American units
.... a US "gill" is 4.8 US fluid ounces, and a "tot" is 2.4 US fluid ounces. Now let's convert the British Navy speak...
Three "wets" (a tiny, tiny sip) equalled 1 sip,
3 sips equalled one gulp,
and 3 gulps equalled one tot.
A Monkey-Approved explanation...
If one "tot" equals three "gulps", then a "gulp" is 8/10 ounce, and a "wet" (which the sailors thought a "light sip") was 1/4 ounce.
Let's put it this way - a "wet" or light sip would finish off a one ounce dram in just four sips, and a "gulp" was the historical equivalent of tossing back nearly a shot.