Jet Ski Hull Care and Repair: Scratches, Gouges, Keel Guards and Beaching Damage

Put the PWC on its trailer or stands, wash the hull with boat soap and let it dry. Use a flashlight at a low angle to show scratches. Pay special attention to the keel line, the front of the hull where it hits the beach, the chines, the area around the pump intake grate, and where the hull sits on the trailer bunks. Sea-Doo's pre-ride checklist says to look at the hull and pump intake for damage or debris every time.

• Look inside the hull (seat off) for water in the bilge, cracks or white stress marks behind any outside damage.
• Press around the damaged area: soft or flexing spots suggest delamination.
• Tap lightly with a plastic handle: a dull sound compared with nearby areas can mean delamination.
• Look for star-shaped cracks around a gouge.

Any of these means the job is bigger than cosmetic. See step 9.

Circle each problem with masking tape and photograph it. This helps if you file an insurance claim after a collision or grounding, and it lets you compare later.

On fiberglass/SMC hulls, light scratches often polish out with a fine marine rubbing compound followed by polish and wax, the same way as a boat hull. On Polytec, the color goes all the way through, so many scuffs are just cosmetic; clean them and leave them, or use products made for polypropylene. Test any compound on a hidden spot first.

For a gouge that doesn't go through:

• Sand the gouge and a little around it to remove loose material and gloss.
• Clean with the solvent named on the repair kit.
• Fill with a gelcoat repair paste or a marine epoxy filler, slightly proud of the surface.
• Let it cure fully, then sand flush with progressively finer paper, and finish with gelcoat or paint and polish.

The gelcoat repair guide has the full method. On the bottom, where the hull grinds on sand and ramps, a tough epoxy filler holds up better than a soft cosmetic paste.

Polytec repairs use plastic welding: Polyvance's method grooves out the crack, welds it with glass-reinforced polypropylene rod in layers, and sands it smooth. It needs a proper plastic welder and the right rod, so for most owners this is a dealer or plastic repair shop job. For shallow scuffs, products made for polypropylene are the only kind likely to stick; most standard marine fillers won't bond.

Boating Magazine's look at Sea-Doo construction confirms the basics without the repair-product sales pitch: Polytec is BRP's own blend of polypropylene and long-strand fiberglass, minor hull damage is fixed with a Polytec welding process Sea-Doo developed, and on models whose deck and hull are bolted together (rather than glued), a badly damaged hull can actually be replaced. Body panels on models like the Spark are also sold individually, so a cracked panel is often replaced rather than repaired, much like a car fender. Ask a Sea-Doo dealer which option applies to your model before paying for a weld.

A keel guard is a tough strip bonded along the keel to take the wear from beaching, ramps and sand. Many PWCs come with a sacrificial keel strip; aftermarket kits are also sold. Discover Boating's installation method for adhesive keel guards:

• Scuff the area to remove mold release and wax (no coarser than 180 grit).
• Clean with alcohol or acetone; don't use paint thinner or petroleum cleaners, which leave a film.
• Apply the primer from the kit.
• Install in warm weather (they say not below 60°F), working from the center outward and pressing firmly.

On a Polytec hull, use only a kit that says it bonds to polypropylene.

Beaching and shallow water damage more than the hull. Discover Boating warns that a PWC's pump can suck up sand, rocks and debris in shallow water. Check the intake grate for bends and the impeller for nicks (see the jet pump guide). Flush the cooling system per your owner's manual after beaching or riding in sandy or silty water.

Stop and get a professional repair for:

• Any crack that goes through the hull, or any hole
• Delamination or soft areas
• Damage at the pump tunnel, intake, ride plate mount, or where the hull joins the deck
• Polytec cracks of any real size

Epoxyworks' WaveRunner repair shows why: cutting out the damage back to solid laminate turned a small crack into a large hole that needed many layers of glass cloth, a backing and lots of fairing.

After any repair, ride briefly near shore, then pull the seat and check the bilge for water. Look at the repair for cracks or lifting edges.

• Approach the beach slowly and never power up onto it (Discover Boating's beaching advice applies to PWCs too).
• Shut off the engine before the water gets shallow, and walk the PWC in. Yamaha's jet beaching tips say to stop the engine in about 3 feet of water so sand and pebbles aren't sucked into the intake, and to push back out to at least that depth before restarting. Your owner's manual may give its own minimum depth.
• Avoid rocks, shells, gravel and oyster beds; sand is abrasive too.
• Watch the tide so the hull doesn't get left grinding on the bottom.
• Check that trailer bunks support the hull evenly and their carpet isn't worn through to wood or bolts.