Ro-Ro Platform

Ro-Ro Platform Latch Cylinder
Hydraulic Self-Locking

The compact alternative to mechanical self-locking. Pilot-operated check valves trap hydraulic pressure on both sides of the piston — holding the bolt in position without continuous pump pressure. Three size options for small to large ramp systems.

80/50·63/40·40/28Three Sizes

25 MPaPressure

SS RodStainless Steel

DNVGLType Approval

Technical Specifications

Parameter	Specification
Product Name	Ro-Ro Platform Latch Cylinder (Hydraulic Self-Locking)
Features	Lock bolt via pilot-operated check valves; hydraulic self-locking
Specifications	80/50S, 63/40S, 40/28*S — front and rear locking
Working Pressure	25 MPa
Piston Rod	Stainless steel
Classification	DNVGL type approval
Application	Ro-Ro Platform

How Hydraulic Self-Locking Differs from Mechanical

Ro-ro vessel ramp with hydraulic latch system

Instead of a mechanical spring, the hydraulic self-locking latch uses pilot-operated check valves (POCVs) integrated into the cylinder ports. When the bolt reaches the locked position, the POCVs close — trapping the oil on both sides of the piston. The piston cannot move in either direction because the trapped oil is incompressible, even without active pump pressure.

To unlock, a pilot signal opens the POCVs, allowing oil to flow and the bolt to retract. The advantage: no spring inside the cylinder body, so the overall length is shorter and more size options are available (three specifications: 80/50, 63/40, and 40/28). The 40/28 is the smallest latch cylinder in the ro-ro range — suited for light-duty ramps and internal vehicle deck doors.

Both mechanical (#14) and hydraulic (#15) latch cylinders carry DNVGL type approval and use stainless steel piston rods. Browse the full offshore hydraulic cylinder range.

Three Size Options for Different Ramp Systems

Ro-Ro Platform Latch Cylinder (Hydraulic Self-Locking)

80/50*S

Largest option. For heavy stern ramps on ocean-going ro-ro cargo vessels and large passenger ferries.

63/40*S

Mid-range. For side ramps, quarter ramps, and medium-duty stern ramps on coastal ferries and short-sea ro-ro vessels.

40/28*S

Smallest option. For internal vehicle deck doors, hoistable car decks, and light-duty ramp latches on small ferries.

Hydraulic Latch Cylinder OEM & ODM

Korea Ever-Power supplies hydraulic self-locking latch cylinders for all ro-ro vessel types. Provide the ramp model, bolt force requirement, space constraints, DNVGL class requirement, and preferred size specification. Complete documentation including DNVGL type approval certificate, material certificates, and test reports. Contact the Korea Ever-Power hydraulic cylinder team for quotation.

Marine hydraulic cylinder configurations

Frequently Asked Questions

Does hydraulic self-locking hold if the pump stops?

Yes — the pilot-operated check valves trap the oil volume on both sides of the piston. The lock holds as long as the trapped oil does not leak past the seals. Seal integrity is verified during each regular maintenance inspection.

Is hydraulic self-locking as safe as mechanical?

Both are DNVGL type-approved for the same application. Mechanical is considered more fail-safe (spring holds even with total seal failure), while hydraulic is more compact and available in more sizes. The choice depends on the specific vessel's safety philosophy and space constraints.

What is the smallest available latch cylinder?

The 40/28*S — 40 mm bore, 28 mm stainless steel rod. Suited for light-duty latches on internal vehicle deck doors, hoistable car decks, and small ferry ramps.

Can I mix mechanical and hydraulic latch cylinders on the same vessel?

Yes — some vessels use mechanical latch cylinders on the stern ramp (highest safety criticality) and hydraulic latch cylinders on internal doors and side ramps (where space is tighter). Korea Ever-Power can supply both types as a coordinated package.

Can the hydraulic latch cylinder be retrofitted?

Yes — Korea Ever-Power manufactures replacements for existing latch cylinders on ro-ro vessels, including matching the mounting dimensions of original MacGregor, TTS, or other OEM equipment. Browse mobile machinery hydraulic cylinders for related applications.

What Our Customers Say

★★★★★Apr 2026

"The hydraulic self-locking latch cylinders (63/40) are 65 mm shorter than the mechanical version we had before — crucial in our tight side-ramp hinge box. Locking performance is identical."

T. Virtanen — Marine Engineer, Finnish ferry operator

★★★★★Dec 2025

"We use the 40/28 latch cylinders on our internal hoistable car deck doors. Compact, reliable, and the DNVGL documentation was accepted by our class surveyor without question."

N. Ivanov — Ship Manager, Russian Baltic ferry line

★★★★☆Aug 2025

"Solid quality. We ordered 80/50 latch cylinders for our stern ramp. After 14 months, the POCV holding performance is still within spec — no pressure decay detected during our quarterly checks."

S. Kim — Fleet Inspector, South Korean ro-ro operator

★★★★★May 2025

"We mixed mechanical latch (stern ramp) and hydraulic latch (side ramp) from Korea Ever-Power. Both sets shipped together with a single coordinated DNVGL package. Made our classification submission much simpler."

L. Bergman — Naval Architect, Norwegian shipyard

★★★★★Jan 2025

"Replacement for original TTS latch cylinders. Korea Ever-Power matched the mounting dimensions perfectly from our drawings. The stainless rod finish quality is better than the original."

J. Reyes — Maintenance Superintendent, Mexican ferry company