[Tagging] Is a ship-lift a crane?

[Graeme Fitzpatrick]

I asked this question on the cranes talk page
https://wiki.openstreetmap.org/wiki/Talk:Tag:man_made%3Dcrane#Shiplift.3F a
week or so ago but no response as yet, so repeating it here.

Would a shiplift https://en.wikipedia.org/wiki/Shiplift classify as a crane?

The one that I spotted which made me wonder is at
https://www.openstreetmap.org/edit#map=18/-12.45943/130.82380 (edit mode in
Bing). Here, the lifting platform goes down a ramp till it's underwater,
the vessel moves over the platform which then lifts it, the platform comes
back up the ramp, travels sideways till it lines up with the correct
"parking" bay, then forward / back into that bay & lowers the vessel onto a
prepared framework for storage / maintenance.

Specifications I have seen say that it can lift 750 tonnes, & the patrol
boats that are probably visible in that imagery are 56 m long, so, while
quite small in regard to general shipping, it's no slouch!

So, it doesn't lift, it pushes upwards - is it a crane?

If not, what do we call it, or just a man_made=ship_lift by itself?

The crane page also makes reference to travel-lifts
https://wiki.openstreetmap.org/wiki/Tag:crane:type%3Dtravel_lift, which it
says "is a mobile crane for transporting ships". However, the talk page has
raised some concerns about them as well:
https://wiki.openstreetmap.org/wiki/Talk:Tag:man_made%3Dcrane#What_is_a_travel_lift.3F

I've had a quick look at only 6 or so of them via Overpass & those ones
were all OK as only mapped as a node on the spot where it actually lifts
boats out of the water, not on a way or area.

Are we OK with following the suggestion noted there & including to only map
these as a node?

Thanks

Graeme
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