motor and waterjet model

I just noticed this interesting design. This 8m boat uses a waterjet to drive it at 10 kn, not a typical design. Why so slow? Can someone help to identify the motor and waterjet model of this RAICHO design? What are the green and gray components on each side of the jet?
Thank you!

 

The writing on the cable says - i think
Temporary installation cable...it is in Japanese!

For an 8m boat going slow..far too many questions and not enough info really. Firstly this is what it could have been designed to do!

 

The thing is, is it efficient to use a waterjet at such speed? why not a propeller?
Secondly, do you know some supplier who provides small waterjets?

 

Franklou

Well, you need to understand the SOR to answer those questions.

If you have been asked to supply a small boat that can run in extremely shallow water, carry big loads and so only need to do 8-10knots....what would you select....a prop...oh but it'll get damaged all the time. Oh..what can i use then?...hmmm..well a waterjet works in very shallow waters, why not use a waterjet.

So is a waterjet efficient at 8-10knots...no. Is it ideal for extremely shallow water, no matter how efficient it is, so long as it does the job..then yes.

You need to understand the SOR before you wish to look at one individual item on a boat to review its efficacy. Which is pointless anyway as a boat is greater than the sum of its individual parts.

 

Could be numerous reasons for going to a waterjet... You may want to not chop someone up if they fall overboard. May want very shallow draft. May be operating in rocky rivers where a prop would get destroyed... Unless you know the requirements you can't judge...

Edit....Ad hoc was posting while I was writing.. saying the same thing...

 

Thank you both! Definitely we need to examine the operational profile when designing a new ship!

BTW, are you aware of established suppliers of small waterjet? I am interested for driving a boat of about 12m at low speed.

 

BTW, are you aware of established suppliers of small waterjet? I am interested for driving a boat of about 12m at low speed.

...small, in what sense? A propulsion device is selected on the basis of operating requirements, as thrust, maneuvrability aso, within the operational envelope.

 

based on the data I collected, a 50-60kW electric motor will probably suit our need. I have not got the hull form yet, so I have to wait a bit to start my calculation and plan the propulsion system.