Whilst the Kriegsmarine's surface fleet, restricted for much of the period after 1919 by the terms of the Versailles Treaty, was relatively small in comparison to the Royal Navy, it did possess a number of highly potent battleships and other capital vessels that could - and did - pose a major threat to British interests in the North Atlantic and Arctic Ocean. Amongst the most powerful were the two battleships - the Bismarck and the Tirpitz. The awesome power of the former was demonstrated by its destruction of HMS Hood in May 1941, although it was itself to be sunk shortly afterward. For Royal Navy planners and tacticians, the close monitoring of the other German capital ships was a pressing need, particularly if the Germans were ever to pose a serious threat to the all-important convoys across the Atlantic and to Russia. Moreover considerable effort went into trying to neutralize the threat either by keeping the German warships penned into harbor or by sinking them.