Hatches & Skylights

Stop water finding its way in through a cracked hatch or skylight

“We used this to waterproof the skylights of our narrowboat. It was easy to apply and did an excellent job.”

– Debbie Donovan, Judge.me review review

Deterioration of the seal between the frame and boat structure is a very common cause of leaks from hairline cracks in boats, particularly around hatches and skylights that are opened and closed regularly. Captain Tolley’s Creeping Crack Cure uses capillary action to seep into these cracks and seal them from the inside, without needing to remove the hatch or replace the seal.

Over time this loosens the fitting and opens fine cracks around its base, often invisible until water starts appearing below.

Captain Tolley’s Creeping Crack Cure uses capillary action to seep into these hairline cracks and seal them from the inside, without needing to remove or rebed the fitting.

a boats portlights and windows which can be sealed if there are leaks from hairline cracks using Captain Tolley's Creeping Crack Cure sealant

“I’ve waited since last November for a dry spell to carry out a repair. The recent fine weather has let me try the Creeping Crack cure, and after a few showers it seems to have finally sealed a persistent drip.”

– William Spencer, Judge.me review

One customer had tried to stop a leak in a boat hatch for eight years with no success – this product finally fixed it, and he said he wished he’d known about it years earlier.

– Ray, verified Amazon customer

Another described it as easy to apply and said it “helped seal up several ports and hatches” on their boat.

– E. Hall, verified Amazon customer

How to use it on hatches and skylights

  1. Clean the area around the frame seal and let it dry completely.

  2. Place something underneath to catch any drips before you start – on a flat or overhead hatch, the sealant can run through the crack on the first application before enough has built up to hold.

  3. Apply a few drops along the seam between the frame and the surrounding structure. A small syringe gives you finer control than the bottle applicator alone, especially around hinges and catches.

  4. Wait 30 minutes, then reapply if the crack is still taking up sealant.

  5. Wipe away any excess immediately with a damp cloth to avoid staining the frame or surrounding surface. Dried stains can be removed with industrial wet wipes.

  6. Leave for a minimum of 24 hours* before opening, closing, or testing with a hose.


*For best results, apply in dry conditions above 10°C / 50°F and keep the area dry while it cures. Cold or damp weather slows curing, and moisture can dilute the sealant before it sets, so allow extra time if conditions aren’t ideal.

Frequently Asked Questions

Do I need to remove the old sealant around the hatch first?

No, the repair happens in situ. Captain Tolley’s goes onto the existing seal and into the hairline cracks in and around it, so the hatch and its current sealant stay in place. Make sure the area is clean and fully dry, and gently pick away anything loose or flaking that would stop the sealant reaching the crack.

The seal between the frame and the surrounding structure often runs deeper than what’s visible, especially where a metal or plastic frame meets fibreglass or wood. If it doesn’t seal on the first try, that’s usually why – simply reapply, and most seams are fully sealed within several applications.

Yes, once cured it stays flexible, so ordinary use of the hatch or skylight won’t crack the seal again the way a rigid filler might.

Let it cure fully before exposing it to water – applying it just before rain or in damp conditions can wash it out before it sets.

Other uses

the surface around boats deck fittings which can be sealed if there are leaks from hairline cracks using Captain Tolley's Creeping Crack Cure sealant

Deck Fittings

Deck fittings - chain plates, stanchion bases, cleats, winches, handrails, and deck fill pipes - are constantly stressed by rigging loads and movement underway, which loosens them and opens hairline cracks for water to enter the boat.

a boats deck roof which can be sealed if there are leaks from hairline cracks using Captain Tolley's Creeping Crack Cure sealant

Coachroofs

Coachroofs combine fibreglass, wood, and metal fittings that all expand and contract at different rates, opening hairline gaps along the joints and seams where water can track in.

a boats windows which can be sealed if there are leaks from hairline cracks using Captain Tolley's Creeping Crack Cure sealant

Windows & Portlights

Fine cracks frequently cause leaking where a portlight or window joins with the structure of a boat.

a model boat which can be sealed if there are leaks from hairline cracks using Captain Tolley's Creeping Crack Cure sealant

Model Boats

Model boats are just as prone to hairline cracking as full-size yachts, often from repeated knocks and handling.