Hey Kapitan, I wonder how these would scale up?
 

https://www.youtube.com/watch?v=MNnB_50Z20I

:hmmm:

If I had to guess, the tolerances would need to be a lot tighter.

Would love to see it but video unavailable :(

Watch On Youtube :03:

"Over the course of two days, BoatTEST’s captains tested a pair of Sharrow Marine props and a pair of Yamaha Saltwater Series II props on a World Cat 325 DC".

My initial thoughts on this would be it most certainly could be scaled up and also multi bladed (seen some pictures of a 5 blade)

Doing a quick bit of research it does seem the cavitation profile would be more concentrated, so the use of a diffuser may be a bonus with it.

A lot of warships today use variable pitch screws this would clearly be a benefit as you don't have to rotate the blade eliminating the gearing.

The main draw backs I can see:

Time to produce, these screws would be more time consuming than conventional ones, plus the casting process would have to be changed drastically too.

Critically would the screw be able to take the torque load of say a DDG ?

Damage to the screw would mean an entirely new screw rather than a blade switch out, this would require dry docking as opposed to in water blade changes. (rare but does happen)

looking at the website they do offer small commercial use of the screw but haven't gone beyond 10m vessels at this time (according to their website)

Overall though it would be a good idea to test this on say a auxiliary vessel then maybe see if it can take the torque of a DDG, the reason for the auxiliary is to see if they are better at saving fuel than azipods.
From what they are saying it does have benefits in the fuel economy range and it also eliminates gearing to reverse the shaft when going astern.

Just my thoughts after a quick read up and watching that video

I have scaled up a blueprint of a Mærsk supply vessel-I went to a special shop and got it scaled double up(the blueprint)

Did not build it-Sold the blueprint to some other guy on a modelforum.

Markus

I was thinking more along the lines of commercial shipping than military use. :D

Scaling it up would be a bear-and-a-half but the increase in efficiency might make it viable. :hmmm:

The vessel is a commercial ship Sailing supply from Esbjerg to the oilrigs.

It's the blueprint you scale up first of all.

Markus

I have put the question out there to a few places and will get back tomorrow on their feed back so far the current feedback is tepid at best.

Can't remember the name of the vessel

I can tell you the story behind my idea of building it-Saw this vessel in the news said to myself I want to build it-from scratch.

So I toke contact to the shipyard who had built her. Got the blueprint. When I saw the prints I decided to scale these blueprint double up.

I never got the money to build her and after some years I sold them.

Here's a link to how these vessel looks like and it was one of these I wanted to build

https://www.maersksupplyservice.com/

Markus

I have put this out to some areas and many of the people that responded seemed to be on the same page.

While this would be good in some commercial cases for a warship it wouldn't be of any use.
They do cite many reasons the main one being the reversing of the sharft and the needing for gearboxes.