How to Replace Gas Struts on Boat Hatches, Seats and Consoles

Open the hatch fully and prop it with a solid stick or have a helper hold it. Photograph each strut: which end is up, where the brackets sit, and the angle. Note whether the shiny rod end points up or down.

Most struts have a printed or stamped label on the body. It often includes the force (in newtons "N" or pounds "lb") and sometimes a part number you can search with the maker or a marine supplier. Write down everything you see. If the label is gone, you'll measure instead.

Measure from the center of one end fitting to the center of the other with the strut fully extended. Measure center to center, not the outside edges. Note it in both inches and millimeters; many struts are sold in metric sizes.

Stroke is how far the rod travels, usually the length of exposed shiny rod when fully extended. If the strut is off the boat you can also measure compressed length. Length and stroke both need to match, or the hatch won't open as far or won't close fully.

If the force is printed, use it. If not, a supplier can help you choose from the hatch's weight, size, hinge position and where the strut mounts; SUSPA, for example, asks for a sketch with the pivot point, weight, center of gravity and opening angle when it sizes a strut. Too weak and the lid drops; too strong and it slams open, strains the hinges and is hard to close. When in doubt between two ratings, ask the supplier, and remember the push gets weaker in the cold.

The printed rating is usually the force the strut pushes with when it is fully extended (often labeled "P1"). Taylor Made advises basing a replacement on the original strut's rating for that hatch, not on a guess, because too little won't hold the lid and too much strains hinges and brackets.

Most boat struts use snap-on ball sockets on ball studs; others use eyelets, clevises or threaded ends. Measure the ball stud diameter and check the thread on any stud you might replace. Buy struts with matching ends, or plan to replace the studs too.

For salt water or open decks, stainless steel struts and stainless ball studs last much longer than painted or plated steel. Stainless costs more but avoids the rusty end fittings that are the usual reason boat struts get stuck or snap off.

With the lid securely propped, lift the small retaining clip on each ball socket with a flat screwdriver and pull the socket off the stud. Don't pry the whole socket sideways hard; if it's seized, a little penetrating oil helps. Some struts have eyelets held by a bolt and nut instead.

Look for rust, cracked plastic or loose screws. Tighten loose screws; if a screw spins in the fiberglass, the hole is stripped (see the through-bolting guide for proper repairs). Replace corroded studs with stainless, and bed any new fastener holes with a little marine sealant so water doesn't reach the core.

Fit the strut in the same orientation as the original. In general, SUSPA recommends installing gas springs with the piston rod facing down, which keeps the rod seal lubricated and slows gas loss. Press each socket onto its stud until it clicks, then make sure the retaining clip is seated. Don't twist the strut or force it in at an angle.

Remove the prop gradually while holding the lid. It should rise smoothly, stay up on its own and close with a reasonable push. Watch that the strut doesn't rub on anything and that the lid closes fully and latches.

Don't drill, cut or burn them. Ask your parts supplier or local scrap or hazardous-waste program how they accept gas springs; rules vary by area.