Well guess what,started the patrol again and........not a single problem
apart from me blowing a great convoy chance of HUGE tonnage,Fleet-tender,motorvessel,2 large merchants,3 medium merchants and to cap it all...HMS Rodney. All that in perfect conditions,choppy sea's,pitch dark,late 1940's and all I sailed away with was 22296grt
...Well atleast its working so musn't grumble,you've all been great help,thank you