Fishing crews' winching and rope-handling experience made trawlers and drifters natural vessels for towing observation and anti-aircraft balloons. The observation balloons raised lookouts high enough to spot submarines on or just beneath the surface. Once convoy escort became widespread, an assortment of small craft could provide that elevated view. A 1917 US Navy planning study nevertheless noted that the balloon only patrolled the distance the convoy advanced during daylight, aside from interruptions such as fog. Its strength was elevation and the ability to direct a surface vessel precisely toward a sighted contact, not independent wide-area searching.
Notable Point · 25:32-26:15
What balloon-towing auxiliaries could - and could not - do for convoys
Fishing crews' rope-handling skills made trawlers and drifters useful balloon tenders, but a 1917 US Navy study also identified the limits of a tethered convoy lookout.