The utility model provides a ships and light boats bow door plays to put angle measuring device belongs to ship domain, solves loading and unloading goods operation in -process operating personnel and can't accurately judge that the bow door plays to put the problem of angle, and this angle measuring device is become by encoder, resilient coupling, automatically controlled unit, nixie display, signal transmission ware, pivot extended shaft and protective housing body group, the protection casing is hollow structure, and including casing, recess, rubber seal, solid fixed ring, rubber tight loop, end cap, welding base, encoder, resilient coupling, signal transmission ware are installed at the protective housing internally, protect the waterproof anticollision function who realizes this measuring device that sets up of casing, the encoder comprises fixed part and rotation portion, and rotation portion, pivot extended shaft, resilient coupling and the pivot of bow door is concentric sets up ensure that the angle change -only information of pivot can transmit in step, the signal transmission route that the bow door plays to put the angle does: the automatically controlled unit of pivot -> pivot extended shaft -> encoder -> signal transmission ware -> nixie display ->.