Attwood SL36-40-5 Gas Spring Lift Support, 40 lb

The Attwood SL36-40-5 is a marine gas spring, the kind of quiet little part you never think about until the day your hatch lid drops on your hand. It puts out 40 pounds of lift, extends to 17.2 inches, and compresses down to 10.2. That gives you 7 inches of travel, which covers a lot of the mid-size hatches, lockers, and seat lids you'll find on a fishing boat or a runabout.

Here's what a gas spring actually does. Inside that 18 millimeter cylinder is a charge of pressurized gas working against an 8 millimeter rod. Push the lid closed and the gas compresses. Let go and it pushes back, slow and steady, holding the lid up right where you left it. No prop rod to fumble with. No lid slamming down while your hands are full of tackle or dock lines. When the charge is right, it feels effortless, and that's the whole point.

This one is sized for real boat jobs. Think livewell and baitwell lids, under-seat storage, anchor lockers, small engine hatches, and console access doors. The 40 pound rating is a mid-range force, so it's a good match for a lid that's got some weight to it but isn't a huge deck hatch. If your old strut was a 40 pound unit and it's gone soft, this is the honest swap.

Both ends use eyelet mounts made for standard 10 millimeter end fittings, so it bolts up to the ball studs or eyelet brackets already on your boat. That keeps the install simple. In most cases you're pulling one worn spring and dropping this one straight in, no drilling, no new brackets.

A few install notes from experience. Gas springs like to be mounted rod-down when the lid is closed. That keeps the seals lubricated and helps the spring last. Watch your geometry too, the spring wants a clean arc through its 7 inches of travel without binding against the frame. And if your lid is wide or heavy, two springs sharing the load will always feel better and last longer than one working alone.

Not sure if the 40 pound version is your spring? The quickest check is the number stamped on the old one. Attwood prints the model right on the cylinder, and SL36-40-5 tells you it's the 40 pound, 17.2 inch unit. If yours reads a different force or length, we carry the neighbors in the SL36 line, so you can match travel and lift instead of guessing. Getting the force right matters more than people think. Too little and the lid won't stay up, too much and it fights you every time you close it.

Gas springs are wear items. They lose a little charge over years of salt, sun, and slamming, and eventually a lid that used to stand up on its own starts sagging. That's normal. Carrying the SL36-40-5 as a replacement means you can bring a tired hatch back to life in a few minutes with a wrench, instead of living with a bungee cord or a stick holding your locker open.

Why buy a marine gas spring instead of a generic one from the hardware aisle? Salt air and constant spray are hard on cheap hardware. A strut that rusts at the rod seal starts weeping oil and loses its hold fast. Attwood builds these for the water, which is why you'll find them holding hatches on center consoles, pontoons, and bass boats season after season.

Attwood has been building marine hardware for over 100 years, and their lift supports are a staple on boats from a lot of different builders. This unit ships in aftermarket packaging, so you're getting the same spring without the branded retail box. The part number is SL36-40-5. If that matches what's stamped on your old strut, you're in the right place.