• A very fine r.p.m. matching for every selected engine.
  This means full power absorption without over or under loading the engine regardless boat speed, according to the engine correct use for a granted long life of the engine.
  
  
• The use of an unique cast stainless steel impeller designed without the constraints to directly match the engine and, therefore, with efficiency and cavity resistance optimised at any operating conditions. This single impeller coupling system can easily meet an high quality productions process.
  
  
• An high jet input shaft, almost at the same level of the engine shaft, thus the cardan shaft works in more favourable condition and it can be shorter. This enables the design of the impeller shaft and therefore the whole water jet unit tail almost horizontal ( 0† ). So to prevent boat trim problems due to strong components of vertical thrust and to allow to better exploit the created thrust, drastically reducing the engine room length.
  
  
• The lowering of the impeller shaft and, consequently, the centre of thrust for better manoeuvrability and boat running stability.
  
  
• The design of a flat and straight duct enabling to drive smoothly the water stream for the best performance.
  
  
• To reduce machinery cost and weight and then the boat overall drag while deleting the marine transmission

Castoldi impeller design is of the true axial flow type.

Thus it operates on a volume system with high flow rate and low pressure and it has a one unique profile design, free from direct engine matching constraints, to meet the best efficiency and cavitation resistance over the hull power and boat speed operation range.

Because of its volume design, increased blades’ tip clearance due to wear do not compromise its efficiency.

Few number of impeller and stator blades allows the easy transmit and discharge of any eventually ingested debris.

This light-weight and most useful facility enables the complete disconnection of water jet from main power source, whilst the engine is idling. Especially useful in engine warm-up and controls’ checks, it can be invaluable in operational circumstances for performing several daily boat stops while maintaining the boat perfectly standstill and without ingesting debris or sand of mooring in dirty or shallow waters and without jet turbulence, yet with full engine power running and instantly to hand.

In conjunction with the movable inlet protection grill, it allows the quickest and most efficient cleaning operation of the jet intake.

It is operated by an electric control through on-off switches.

All bearings are of the rolling type and lubricated by the same oil lubricating the gear wheels sets.

They never come into contact with sea water and can last for thousands hours.

The input shaft rotates inside the fin’s oil chamber ; therefore it is perfectely protected by any debris should enter into the duct and twin around it. Furthermore the fin allows to support the impeller ( with standard oil lubricated roller bearings ) avoid easy vulnerable water lubricated tail bearing

The improved Castoldi water intake is positioned very close to the transom. This avoid aeration in rough conditions fast operations and increases performances by recovering the boundary layer stream.

The inlet grid protects the water intake from suction of floating debris and performs self-cleaning operations rejecting the same through the shift opening of the two alternated sets of bars, electro/hydraulically controlled, from the wheel house by the helmsman itself when a pressure drop arises into the jet duct indicated by a manovacuometer.

The flush mounted grid’s bars have smooth hydrodynamic profile able to control the water flow with minimal losses.

This is absolutely the most efficacious anti-clogging system as it prevents debris to enter into the jet duct driving it away with a simple and quick operation.

It is also very important where a water jet powered rescue vessel needs to draw near to swimmers or it is in close proximity to loose lines and wreck debris.