Attwood SL36-50-1 Gas Spring 50 lb Lift Support

The Attwood SL36-50-1 is a gas spring, the quiet workhorse that holds a hatch or lid open so it doesn't slam down on your hand. You'll hear these called gas springs, gas struts, or lift supports. Same part, different names. It's a sealed, gas-charged cylinder with an 8 millimeter rod riding inside an 18 millimeter body. Push the lid closed, let it go, and the spring eases it back out under its own pressure. Simple part. But when the one on your boat gives up, the whole compartment turns into a two-handed job.

Attwood has been in the marine hardware business for more than a century, and gas springs are exactly the kind of unglamorous part they've built their name on. This isn't something you think about until it fails. When it does, you want a direct replacement that matches the original spec and gets on with the job.

This spring is rated at 50 pounds of output force. That's the number that matters most when you're matching a replacement. Output force is how hard the spring pushes as it extends, and it needs to roughly balance the weight of whatever it's lifting. Too weak and the lid won't stay up. Too strong and it fights you on the way down. Fifty pounds sits in the middle of the range you'll find on mid-size hatches, seat bases, and storage lids. It's a common mid-range spring, which is why it turns up as the replacement on a lot of different boats.

How do you know a gas spring is done? The lid starts drifting closed on its own, or it needs a shove to stay up, or it opens slow and lazy when it's cold out. The gas charge bleeds down over years of cycling, and there's no rebuilding it. You replace it. The good news is the fix is cheap and quick.

The geometry is straightforward. Compressed, it measures 10.2 inches end to end. Fully extended, it runs 17.2 inches. That works out to 7 inches of travel, the stroke the rod covers as the lid swings open. When you're replacing a worn spring, measure the old one in both positions and match all three numbers. Force, closed length, and travel together decide whether the new spring drops in clean or leaves you re-drilling mounts.

Both ends use eyelet mounts with a 10 millimeter socket. Eyelet ends are the loop-style fittings that pin to a bracket, rather than the ball-stud sockets that snap on. They're common on marine hatches because they hold up to vibration and won't pop loose in a chop. The rod is 8 millimeters and the cylinder body is 18 millimeters, standard dimensions for a spring in this force class. If your old spring used the same eyelet ends, this one bolts straight into the existing brackets.

Where does it go? Livewell and baitwell lids, under-seat storage, console hatches, engine hatch supports on smaller boats, rod locker lids. Anywhere a panel needs to stay up on its own and come down gently. Gas springs like this one generally last longest mounted with the rod pointing down when the lid is closed, which keeps the seal lubricated and holds the charge. Give the rod an occasional wipe and keep it clear of grit and salt.

It ships in bulk packaging, so you're getting the spring itself without a retail blister pack. That's how rigging shops and boat builders buy them. If you're chasing a sagging hatch, confirm the 50 pound force and the 10.2 inch closed length against what you've got before you order. Then it's a couple of hand tools and a few minutes to have the compartment holding itself open again.