Lid Supports and Arms for Hatches and Lockers

Managing the opening of lockers on a boat is not just a matter of convenience, but of operational safety. An undersized arm cannot counter the weight of the hatch, while one that is too rigid can strain the hinges or damage the gelcoat when closing. Choosing the right support requires attention to the opening radius and the force needed to hold the load in a stable position, especially underway when stresses are greater.

In our years of shop work we have seen too many failures caused by inadequate steel or mechanisms seized by salt. Using AISI 316 components is the minimum standard for anyone who wants to avoid rust compromising the arm's function after a single season. Corrosion resistance is fundamental, as is the precision of the pivot point, which must distribute forces correctly to avoid lateral stress on the mounting points.

When selecting a locker arm, always consider the actual weight of the panel it must support. If the hatch is heavy fiberglass or has solid wood inserts, the arm must have a Safe Working Load (SWL) well above the measured static weight. Do not forget to check the available space inside the locker: some models require a specific depth to fold correctly without interfering with the locker contents.

Nautiba supports your selection with targeted technical advice. If you have doubts about compatibility or the force required for your specific locker, contact us before proceeding. We analyze the technical specifications together to avoid purchasing errors, focusing on solutions that last over time and hold up in the harshest marine environment.

How to choose the right arm for your locker

• Check the material: always favor AISI 316 stainless steel to prevent premature oxidation.
• Assess the hatch weight: calculate the force required in kg-cm to keep the locker open without effort.
• Measure the footprint: check the internal space available when the locker is closed to avoid mechanical interference.
• Check the locking system: some models feature an end-of-travel catch that holds the hatch even with the boat heeled.
• Verify the mounting type: make sure the base is compatible with the thickness of the mounting panel.

Which materials provide the longest service life in a marine environment?

AISI 316 stainless steel is the benchmark material for marine use thanks to its molybdenum content, which significantly increases resistance to corrosion caused by sodium chloride and salt-laden moisture.

Can an old arm be replaced with one of a different brand?

Yes, it is possible, but you must carefully verify the center-to-center hole spacing and the arm stroke. If the dimensions do not match, you risk straining the hatch hinges.

What should I do if the locker will not stay open?

A hatch that falls closed usually means the arm has lost pressure or the hatch weight exceeds the component's rated load capacity. In that case, replacement with a higher-capacity model is necessary.

Do arms require periodic maintenance?

A quick rinse with fresh water after each outing and a light coat of marine protective spray are enough to keep the mechanism running smoothly and prevent moving parts from seizing.

How do I calculate the required load for a heavy hatch?

For an accurate calculation you need to consider the hatch weight and the lever arm. If you do not have the specifications, contact us with the panel dimensions and material and we will help you size the correct component.