Skiffs appeared for the first time in Ultima V, where the Avatar could either purchase one from a shipwright, or have it included with a frigate. They were necessary to reach the shallow waters that the larger frigates couldn't.
In Ultima VI, skiffs gained the ability travel over all water surfaces, and no could longer dock with frigates. However, a strong companion now was able to carry the skiff to also safely pass underwater rivers.
The Ultima 6 Project
In the Ultima 6 Project, the various shipwrights in Britania tell the Avatar, that due to the current war situation they do not have any skiffs to offer. Dupre reacts with relief to these news, having feared the Avatar would force him to carry the skiff. This banter is a reference to the original Ultima VI, where it indeed was the best idea to let Dupre as the strongest character carry a skiff in the inventory.
|“|| Small double-lock rowboats, used as lifeboats on frigates, skiffs can make their way through all but the shallowest mud or swamp. Widely used for exploration of riverheads and mountain streams, they are also occasionally found being put to more recreational uses in townes. They provide a charming way to follow the little estuaries that crisscross Britannia. In fact, there are said to be little-known places unreachable by any other means. However, skiffs are unsafe on deep ocean waters.|
|“|| Several of the port towns along the shores of Britannia boast of craftsmen renowned for their dedication to the construction of safe, dependable sea vessels. Whether you need a small skiff to get upriver, or a mighty sailing vessel for open sea travel, the local shipwrights will be more than happy to discuss terms. It is wise to pay attention to information about local sea and wind conditions before setting out in a new craft.|
|“|| These are handy for getting around. A strong fellow like Dupre can carry one, if he's not too loaded down to start with. Having one with you is a good idea, particularly if you're exploring caves, where you may run across underground lakes or rivers.|