NEED TO KNOW

to get everything in place before it cures.

KEEP YOUR BOAT’S HULL SAFE

• A lot of it is TLC – know your boat, know what’s already there and what’s new. Any new starcrazing in the gelcoat is always worth checking out.

• Note any cracks in the gelcoat around cleats or winches, and check whether the backing plate is large and secure enough underneath. Sometimes owners have asked lifeboat crew to set up a tow on what they assumed was their boat’s strong point, but the tow could have pulled out the whole deck.

• After any repair, look out for hairline cracks appearing around it. They could be a sign that the repair hasn’t bonded properly.

• Speak to your insurer or marine surveyor if you’re unsure, especially after a grounding.

It also doesn’t match the advanced composites our latest lifeboats are made with. ‘When different materials to the hull are used in a repair, you can get weakness between the new material and original, which is then compounded by loading forces, and the twisting and bending motions of the lifeboat,’ says Pete. We’ve now started using the ‘prepreg’ technique on Shannon and Tamar class repairs, where a woven layer of fibres comes ready-impregnated with the right amount of epoxy resin. The repair is cut to size, formed to the hull, and then tucked up in a heated blanket to cure it at 80–90˚C. The resin flows into the fibres, wets them out, and drives out air bubbles to make a very strong seal. Vitally, the repair matches the composition of the original hull, making for a more uniform, stronger and longer-lasting repair.

Ready To Repair

Once the repair has been specified, the damaged area is cleaned of salt water, oil and grease, and then dried out. Paint is sanded back and, if there’s extensive damage, the outer skin may be sawn away to uncover the cracks in the core. Because prepreg repairs match the advanced epoxy material of the original hull, these types of repairs aren’t limited by size – matching materials give much greater flexibility. ‘We can take more away than is actually damaged, to simplify the repair or avoid a new join being in a highly loaded area, such as under a cleat or a windlass,’ says Pete.

In areas with sandwich construction, the inner skin is repaired first, then the foam core replaced, and finally the outer skin, all bonded together in the heat curing process. With the paint reapplied, the lifeboat is ready to resume its lifesaving duties. In the future, ready-prepared kits including

CASE STUDY: PREPREG REPAIR ON A SHANNON

A Shannon class lifeboat was damaged when completing a manoeuvre. What looks like a scratch in the paintwork hides greater damage beneath. As the outer skin deflected inwards, it shattered the foam core. Completed last year, this was the first Shannon repair to use the prepreg technique.

Damaged core removed, with an internal former in place to maintain the