Short Tow - less than 200 metres (measured stern to stern).

Long Tow - Over 200 metres. Diamonds on each vessel.

Short Tow - inconspicuous or partially submerged, under 200 metres.

Long Tow - inconspicuous or partially submerged, over 200 meters.

Restricted Manouvreability - Keep Clear - (ball, diamond, ball - used in any of the situations given above.)