Planning a workboat build

I pursued the water jet possibility by talking to a former navy colleague. Some of our larger (by current Swedish standards that is) naval vessels utilize water jets and the have no problems with ice clogging up the intakes (I don't know how they've solved the possible cooling issues though). He did however confirm, in general terms of course, that jets are sensitive to ice accumulation on the control mechanisms as well as not being designed for operating in reverse in ice. Neither of these design aspects have any impact on the navy ships, but for my kind of operation it most certainly would.

 

Hi Magnus,

Your navy friend probably talked about the Visby-class corvettes, some of the reasons the Swedish Navy choose for Kamewa waterjets there; is issues with stealth for submarines when having traditional prop propulsion, and the added manoeuvrability with jets, and the shallower draft the jets give, and some more I think.

All in all these things made it worth for the Swedish Navy to deal with the jet's issues here as well I guess.

And having an FRP sandwich plastics and carbon fibre composite hull, I'm not sure how much ice capabilities the Visby-class corvettes actually have anyway.

Naval Technology → Feb. 4, 2009 - Analysis - Waterjets Propel Sweden’s Visby to Success

​

​

​

​

‘‘ Visby-class corvette on the prowl in the littoral environment ’’​

P.S. - - See also: - Naval Technology → Projects - Visby-class

​

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Combined marine propulsion power systems:
| - CODOG * - | - CODAG - | - CODLAG - | - CODAD - | - COSAG - | - COGOG - | - COGAG - | - COGAS - | - CONAS - | - IEP or IFEP - |
* The Visby-class corvettes utilizes the CODOG combined marine propulsion power systems.

 

Yes, the Visby-class. They have apparently proved themselves to be very capable in ice. The main issue has, afaik, been making sure that the area behind the vessel is clear of ice (as in not letting ice accumulate on actuators and other moving parts). When operating in reverse the trick is to only partially lower the buckets which in turn allows some of the thrust to be directed rearwards and thus clearing it of floating ice that could otherwise damage the jets.
As far as GRP or other fiber reinforced plastic hulls they work well in ice, there are even a few vessels built in GRP with ice specifically in mind. It would seem that GRP aren't any worse of a choice than aluminum, but the aluminum having a distinct benefit of being faster to repair should damage occur.