Hydromechanical (HM) Control

The Hydromechanical (HM) control provides proportional operation of the reversing deflector (bucket) when actuated by a push/pull cable from the helm. The HM control converts low lever-efforts at the helm to hydraulic actuation of the reverse deflector, even at full throttle. The HM control is available on the UltraJet models 251, 305, 305HT, 340, 377, and 410.



The Hydromechanical control provides low-effort proportional control of the reversing deflector (bucket). Push/pull Type 33C cable movement is converted to hydraulic actuation of the deflector at the hydromechanical unit. The Hydromechanical control unit is mounted to the side of UltraJet models 251, 305, 305HT, and 340. PLAY VIDEOS QuickTime movies of boats with hydromechanical control. Twin-jet police boat maneuvering (1.9MB). Twin-jet Navy patrol boat (1.6MB). Above videos courtesy of ABCO Industries Single-jet security patrol boat (11.1MB). Video courtesy of Hemnes Mek Verksted	Hydromechanical Control Features • Low effort proportional control. • Smooth application of forward, reverse, or neutral thrust for optimum boat maneuverability. • Multiple stations using master/slave helm units with connecting push/pull cables. • Helm lever deflection provides a visual indication of deflector position. • Simple to maintain and service. • No electrics or electronics. • Compatible with most steering helm units from reputable suppliers. • For use with standard or hydraulic power-assisted steering. Hydromechanical Options • Open-center valve for jet-driven hydraulic pump (Code K). • Closed-center valve for pressure compensated pumps (Code K1). • Open-center valve for jet-driven hydraulic pump plus power steering (Code K2).

Hydromechanical Control Details

	Hydromechanical control assembly shown mounted to an UltraJet 305. The 3 inch (76 mm) travel of the mechanical push/pull cable actuates the hydraulic valve to send hydraulic fluid to the reversing cylinder. A feedback link from the end of cylinder provides proportional positioning of the reversing deflector relative to push/pull cable travel. Click on photo for larger image.

	View of the UJ305 reversing cylinder and connection to the reversing deflector (bucket). This installation is typical for the UltraJet 251, 305, 305HT, and 340 models. Click on photo for larger image.

	Single and two-lever helm control units with 3 or 4 inch stroke, from most reputable manufacturers, may be used to actuate the UltraJet Hydromechanical control. Typically customer-supplied to conform with console configuration. Use 4 inch stroke helm units to allow for motion lost in bends of the push/pull and still achieve the full 3 inch cable travel at the HM control.

	Connection of the push/pull cable to the lever on the Hydromechanical control assembly. Click on photo for larger image. SEE SECTION 6 OF MANUAL SUPPLIED WITH THE JET FOR ADDITIONAL INSTALLATION INFORMATION.

	Diagram and table showing relative movement of the helm lever, cable, valve spool, hydraulic cylinder rod, and reversing deflector for AHEAD and ASTERN operation of the boat. Click here for a JPEG of this document.

	Assembly drawing of the Hydromechanical control with component part numbers. Click below for PDF drawings of HM control assembly by UltraJet model. 2002-003-0AM/0DF for UJ251 2002-004-0AH/0DB for UJ305 2002-007-0AX/0DU for UJ305HT 2002-005-0AD/0DY for UJ340 Note: These drawings are subject to revision so owners should first refer to Section 6 of manual supplied with your UltraJet unit.