Attwood SL29-140-1 Gas Spring Lift Support 140lb

The Attwood SL29-140-1 is a gas spring, sometimes called a lift support or gas strut, built to hold up a hatch, lid, or panel and take the weight off your arms. It puts out 140 pounds of force, extends to 36.3 inches, and uses an eyelet fitting on both ends. If you've got a heavy engine hatch, a livewell lid, or a storage locker that won't stay open on its own, this is the part that fixes it.

Let's talk about that 140 pound rating, because it's the number that matters most. Gas springs are sized by the force they push with, and 140 pounds is a strong one. It's meant for a heavier lid, or a panel where you're using a single spring to carry the whole load. Match the force to what you're lifting. Too little and the lid drifts shut on you. Too much and it fights you every time you try to close it. If your old spring was a 140, this one drops right in.

The dimensions tell you whether it'll physically fit your opening. Compressed, it measures 21.1 inches from eye to eye. Fully extended, it's 36.3 inches. That's 15.2 inches of travel, which is how far the rod strokes out as the lid swings open. Before you order, measure your existing strut end to end in both the open and closed position, or measure the mounting points on your hatch. The compressed length has to be short enough to tuck away when the lid is shut, and the extended length sets how far the lid opens.

Both ends use an eyelet mount, so this one bolts through a hole rather than snapping onto a ball stud. The rod is 10 millimeters and the cylinder body is 22 millimeters, with a 13 millimeter socket spec at the fitting. Eyelet ends are the simple, sturdy option. You run a bolt or a clevis pin through the loop and you're done. There's no plastic socket to wear out or pop off on a cold morning.

Where does a spring like this earn its keep? Boat hatches, mostly. Think engine compartment lids on a center console, in-deck storage and fish boxes, livewell and cooler lids, lazarette hatches, and heavy seat bases that flip up for storage underneath. Anywhere you've got a panel that's a pain to prop open, a properly sized gas spring turns it into a one-hand job. It's an Attwood marine part at heart, so it's used to living around salt air, sun, and spray, though plenty of folks use the same struts on RV compartment doors and truck toppers too.

If you're replacing a tired strut, the giveaway is a lid that used to stay up and now sags or slams. Gas springs slowly lose their charge over years of cycling, and there's no refilling them once they're spent. You just swap in a fresh one. Pull your old spring, read the force and length off the label if it's still there, and match it. If the label's long gone, measure the compressed and extended lengths, and count on the 140 pound rating for a heavier lid that needs real support.

A couple of install notes before you order. This listing is for the gas spring itself. Mounting brackets, ball studs, and bolts aren't listed as included, so plan to reuse the hardware that's already on your hatch, or pick up the fittings you need separately. Mount the spring with the cylinder body up and the rod pointing down when you can. That keeps the internal seals lubricated and helps it last longer. And check whether your lid needs one spring or two. Heavier hatches often run a pair, one on each side, so you may need a second unit to balance the load evenly.