Let's talk about [old] submarine propeller designs (nothing confidential)

[Aktungbby]

I was being humorus U were right the first time! Subs don't give a bilgerats ass about fishing boats...that's just 'collatertal damage'. Although I'd imagine getting tangled in a net causes 'cavitaion' too!http://www.globalsecurity.org/military/systems/ship/systems/shrouded-propulsor.htm

A shrouded propulsor (not a 'ringed propeller') is a directional collar around the submarine's propeller. It lowers the passive sonar signature of the sub and provides improvement over exposed propeller designs in both efficiency. The Improved Los Angeles (SSN-751 onwards) have a shrouded propulsor, as do all subsequent classes of American attack submarines. At least one Russian KILO has had its propeller replaced by a shrouded propulsor, which is now used by new US and British nuclear submarines. A shrouded propulsor is identical to a standard shafted propeller, with a cylindrical ring of metal attached at the the tips of the propeller blades around the full circumference....Improved design in submarine screws (propellers) significantly reduces cavitation. Cavitation is reduced by the shroud, as the duct maintains higher pressure around the blade tips and prevents cavitation bubbles from forming. One method of improving the efficiency of propellers uses a pipe shroud to encase the propeller. This shroud or nozzle forces more of the water directly out from the propeller. And by ducting water flow through the shroud, tip vortices can be harnessed to provide thrust.

[FPSchazly]

Originally Posted by Aktungbby

I was being humorus U were right the first time! Subs don't give a bilgerats ass about fishing boats...that's just 'collatertal damage'. Although I'd imagine getting tangled in a net causes 'cavitaion' too!http://www.globalsecurity.org/military/systems/ship/systems/shrouded-propulsor.htm

Oh, very good haha you got me there. That was some straight faced dead-pan there!

[Aktungbby]

Originally Posted by FPSchazly

Oh, very good haha you got me there. That was some straight faced dead-pan there!

What's really going through any passive sonarman's cavitation bubbles head:

[Kapitan]

if you want a prop design have a look at B414 Danil Morisovisky a Victor III (improved dubbed IV) has counter rotating propellers



Victor III in dry dock in the 90's



Counter rotating props which have been tangled up close up of the screw on the Victor III



Prior to scrapping this is the back end of the K222 the lone papa class or Project 661



Romeo class submarine showing her shrouded screws later veriation is the type 033 ming



Back end of the beluga class !



Back end of the Akula I



Project 705 Lira or Alfa to you and me

B396 Tango Class by Blair shaw, on Flickr

Tango class submarine B396 Moscow showing triple screw design with shrouded screws

[p7p8]

Very nice photos Kapitan!


Have you more?

[Kapitan]

Originally Posted by p7p8

Very nice photos Kapitan!


Have you more?

Loads are you looking for something specific ? or specific type of boat ?

[p7p8]

Oh, I see, you have superb link to photos on signature