NTNU and SINTEF doesn’t claim that using air bubbles to “lubricate” the underwater hull of ships is a new invention, nor that there are not other uses for air bubbles on ships, or otherwise.
From the OP:
As to whether a ship fitted with the system gets deeper draft while the system is in use (at speed)?
I don’t know, but think that it would be so little that it doesn’t affect the the wetted area significantly. (Or put the load line under water)
When a floating drilling rig hit shallow gas it definitely has an effect.
That I can vouch for, having experienced it on a drillship operating in the South China Sea (twice in fact).
In that case, as with subsea volcano eruption, the amount and size of bubbles are VERY different from what is the case in a controlled system.
Highly doubtful, especially when considering the tenacious nature of marine growth in general. Your question though is amongst the reasons that extensive trials, a long term affair to be sure, would be an absolute necessity. Of particular interest is the resistance capacity of that thin layer of slime that seemingly ignores the removal mechanisms deployed by the most advanced protective coating schemes - and that’s because it happily exists within the protection afforded by laminar flow during voyaging. Luckily, due to that thin layer, sometimes almost transparent, it contributes little drag for shipowners to worry too much about. However, were the vessel to layup short or long term, it ‘attracts’ other species to join the party.
damnit, the popups are so annoying as to prevent responses so sorry about the empty ones that must be above here BUT: I called bs on the air bubbles floundering a ship but the realized that were the ship essentially floating on air it would sink until the air pressure under the hull was sufficient to equalize the force of the water ……… by my estimation that’d be about a 40K HP air compressor the size of a c5 tanker? despite a fishes scales, they still use saliva or other slick stuff instead of a air compressor.
