+<p>
+
+So you should specify your vessel capacity. You can enter things
+like:
+<dl>
+<dt>sloop
+<dd>The capacity of a sloop, exactly
+<dt>20t 13kl
+<dd>20 tonnes (20,000kg), 13 kilolitres (13,000l)
+<dt>sloop - 100l 100kg
+<dd>The capacity of a sloop minus 100l, minus 100kg
+<dt>2t plus 500kg minus 200kg
+<dd>2300kg, with no limit on volume
+</dl>
+
+Formally, the capacity is a list of terms, all but the first preceded
+by one of <kbd>-</kbd>, <kbd>minus</kbd>, <kbd>+</kbd>,
+<kbd>plus</kbd>. Each term may specify a mass and/or a volume
+(separated by a space), as a number followed (without an intervening
+space) by a unit (<kbd>t</kbd>, <kbd>kg</kbd>, <kbd>kl</kbd> or
+<kbd>l</kbd>). The first term may be a ship name or abbrevation
+instead. If the first term specifies only one of mass or volume, all
+the subsequent terms may only adjust that same value.
+
+<h3>Expected losses</h3>
+
+In theory if you were guaranteed to have a trouble-free voyage it
+would be worth trading goods at very low margins. However, in
+practice problems can arise: you may be attacked and lose your stock,
+or market conditions may change between your collection and delivery
+of the goods.