SeaStar Solutions H-20 Series Heavy Duty Hynautic Helm AssemblySeaStar H-20 Series Heavy Duty Hynautic Helms are for use with SeaStar’s rugged 3-line Hynautic steering systems. These heavy duty helms combine one or twobi-directional axial piston pumps with pilot checkand make-up check valving. The result is a unitwhich prevents rudder feedback, is very efficient(even at low RPM), and is immediately adaptableto multi-station use.A wide choice of helm displacements and cylinderconfigurations make it easy to spec a system whichcan handle a variety of large boat performancerequirements and accommodate most userpreferences.Features:Heavy-duty helmAvailable in different displacements to accommodate most applicationsAvailable with 1″ straight shaft or 3/4″ taperedMade with marine-grade materialsMeets or exceeds applicable requirementsAdaptable to multi-station useMax steering wheel diameter: 36″Specifications: Part Number Displacement Shaft Style Diameter & Type Keyway Integral Valving H-21 2.75 cu. in. 1″ Straight 1/4″ Square Yes H-22 2.00 cu. in. 1″ Straight 1/4″ Square Yes H-25 2.75 cu. in. 3/4″ Tapered #9 Woodruff YesH-26 2.00 cu. in. 3/4″ Tapered #9 Woodruff YesDimensions:SeaStar H-20 Series Hynautic Helm Application ChartNote: In the chart below, tubing diameter is based on the distance from cylinder to the farthest helm.For Vessel Sizes Up ToHelm Pump ModelSteering Wheel TurnsRequires Cylinder ModelTubing Diameter – 40 ft. or lessTubing Diameter 40 ft. or moreMax Suggested HP Planing Hulls35′ – 50’H-21 or H-255.0HC5350 or HC53561/2″5/8″450 HP40′ – 50’H-21 or H-256.8HC5351 or HC53571/2″5/8″750 HPDisplacement Hulls – Tug Boats, Net Haulersto 30’H-21 or H-255.0HC5350 or HC53561/2″5/8″200 HP30′ – 35’H-21 or H-256.8HC5351 or HC53571/2″5/8″250 HPDisplacement Hulls – Work & Pleasure Boatsto 40’H-21 or H-255.0HC5350 or HC53561/2″5/8″300 HP40′ – 45’H-21 or H-256.8HC5351 or HC53571/2″5/8″350 HPSailboats – Skeg Rudderto 40’H-21 or H-255.0HC5350 or HC53561/2″5/8″-40′ – 45’H-21 or H-256.8HC5351 or HC53571/2″5/8″-Sailboats – Spade Rudderto 40’H-21 or H-255.0HC5350 or HC53561/2″5/8″-40′ – 45’H-21 or H-256.8HC5351 or HC53571/2″5/8″-Click to Download SeaStar H-20 Series Hynautic Helm Application Chart