A few remarks on canning.
Canning occur for several reasons like pressure difference between the exposed thin plating, riveted or welded to the frames, seabattering and weldingstresses during construction. In addition the hull gets dents during maneuvering, accidents by wrong blowing (positive dents) and depthcharging. The extent of dents and canning depend on the lifetime and operational history of the relevant submarine. Normally the VIIC was not very susceptible to canning as the light superstructure and casing was riveted thus no welding stresses. The saddletanks have a large section which is pressureproof see my image below, were the casing has virtually no canning and only the non pressureproof section the fueloil/ballasttanks 2 and 4 have typical maneuvering dents. The upper image is of the U 995 having done her service some 20 years which is possibly more than 4 times the normal war lifetime of a VIIC. I believe the average canning and pressurehull corrosion marks which are applied by some modelbuilders are overdone. Don't copy the museum U-995 the casing is restored by welding the casing plates which have weldingstresses and the pressurehull has an excessive corrosion by being laid up without antifouling or maintenance for several years, In this condition she would not be approved for service.
The lower photo is of the U_995 in Trondheim May 1945 after she had been in quite rough service in Arctic waters for almost 2 years pretty much a average wartime service for a VIIC. By looking at the casing and saddletanks you`ll hardly see any dents or canning.
I clearly see the fun of canning and weathering, but if the aim is an accurate model one should behave.
