nothing new really
Heave compensation is as old as, oil Industry has been heave compensating drilling ships since way back when.
Also used on diving support vessels to 'hold' saturation chambers steady.
US Navy boffinry chiefs say they have successfully tested a cunning, heavily augmented crane which allows containers to be loaded on and off ships tossing on the waves out at sea, removing the need for a harbour when mounting an invasion or delivering humanitarian aid. The LVI Lo/Lo wibbley-wobbley crane in action. Credit: ONR …
Yeah, but it's not heave compensation. That just has to keep a load in one place in space, which is an entirely simpler problem to keeping a load in one place relative to a moving point (the other deck). Firstly you have to sense the deck and secondly you have to accelerate the load around to make it stay in the same place, particularly laterally, which isn't easy on the end of a cable. Also you probably need to adjust the plane of the bottom of the container to match the receiving deck, which is probably what the gubbins on the crane head and the extra lateral cables are for.
So, simple heave comp it ain't.
Offshore installations are supplied almost exclusively by boat and of course not much of it is explosive, but most of that that gear ain't exactly light. Or cheap.
However, claiming that this fancy-shmancy new crane allows loading/unloading in 'up to 1m waves' isn't exactly going to rupture anyone's BOP with excitement. We wouldn't have been able to get any oil out of the North Sea on a commercial basis if the supply vessels there couldn't cope with a fair bit more than this on a daily basis. Hell, a 2m swell is almost calm and things only get dicey when it's a good bit rougher than that.
I can see how the crane can accommodate shifts in the position of the load due to vessel movements, but how is it to accommodate variations of position in the other vessel. Since the crane is likely to be on the the vessel supplying the load, there is a good chance that the vessel to which the load is being delivered is going to be smaller, and therefore subject to even more violent movements. The only solution I can think of is for the crane to lower a sensing pack onto the other vessels deck, in the vicinity of the delivery point to allow it to assess the differential movements of the two vessels.
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