Ketches are massive starships used by the Fallen that are capable of inter-system travel. The Fallen arrived on these ships in the wake of the Collapse, disembarking to pillage the remnants of human civilization. The Awoken of the Reef also employ Ketches presumably captured from Fallen foes during the Reef Wars, as a number of Ketches in Reef livery participate in the battle against Oryx's Hive fleet over Saturn. You can often distinguish a Ketches affiliation with a house by the colour of a line painted around the main engine. In Destiny 2 Ketches belonging to the House of Dusk have a purple line while the Ketch found in the Tangled Shore may belong to The Spider. 
Overview and Layout
The overall design of the Ketch falls in line with the organic nature of most of the architecture seen within Fallen culture. However given the current status of the Fallen as a species they are often dirty and held together with pieces of metal that their crews come across. Also of note is the Ketch's status as a space ship, their purpose during the Eliksni's time with the Traveler has never been given and therefore what they were originally is still subject to speculation. Despite their condition they still serve as capable warships for the Fallen and their power and resilence could be considered a clear sign of the Travelers influence on the Eliksni people.
List of appearances