Repair Schemes

The Tabs below provide advice and support for maintaining and repairing you Lightning. John Claridge is also a good source of advice and is always willing to provide information and materials if needed for DIY repairs, see the ‘Our Builder’ page under the Class Info Tabs for contact details.

Center Case Repairs
Loose Mast Kicker Fitting
Slot Gasket Repairs
Hull Leaks

Center Case Repairs

Info from a post on the Forum

One of the repairs that is considered most difficult is when the Center Case leaks through the Desk to Hull moulding joint. Below is some advice from the Forum about how to deal with this repair

Once the slot gasket is removed it is a fairly easy repair, there are a couple of way you can do it.

First off you need to find the leak, soapy water and a bit of pressure in the hull usually comes up trumps, after I found my split, I got a dremel and gently ground a small V shape along it, I then filled the gap with epoxy with some microballons (to make it slightly flexible) and worked it into the gap (opening gap up with small screwdriver)

After it was filled I placed glass tape over it, to stop it running.

Don’t be afraid to remove material. If you don’t have a dremmel, then the corner of a sharp chisel, held so it makes a V, and pulled backwards, will work, too. As with Laser gunwales, whether you use an epoxy paste, or a Polyester paste is up for debate. Epoxy sticks better in theory, but is a different chemical, and has different bend properties, so may crack out more easily. Personally (Rupert) I’d use epoxy, but it isn’t a completely clear cut thing. Sikaflex does. stick well, but not for ever, and once on it is difficult to remove to do the job properly, and neither epoxy or polyester will stick to it

it is important to make sure it is 100% dry before you try to glue it. Also don’t be shy taking out the old material, as it will make filling the gap easier.

The other way to affect this repair is to use sikaflex (marine grade) as above it is quite durable and very flexible so maintains a good joint, but can be difficult to remove if you later decide to glass the repair.

Loose Mast Kicker Fitting

On some of the older boats the Mast Kicker fitting works loose and the rivets can pop out and jam in the mast tube. It is quite a job if this happens to free the mast, without putting a groove, or worse in the mast tube, which then also needs repair.

If both rivet holes are reasonable intact then the rivets can be drilled out and replaced, but you need long steel rivets to do that and there is a limit to the oversizing that can be achieved.

If that fails then bolts/screws are an option.

I took out the mast heel, got a couple of feet of dowelling and inserted it up the mast. Marked the position of the rivet holes and also where the dowel was positioned relative to the bottom of the mast so I knew how far the dowel needed to go back in to be in the same position again.

Bit of blue-tack on the dowel over the rivet hole mark, top hole first, to hold on the nut. Stainless Steel screw through the rivet hole, then dowel back in with the nut on it. I used a moderately longer threaded screw so I could hold the screw and pick up the nut, without messing about with a screwdriver.

It was actually quite easy to pick up the nut and start the thread.

Taped an opened ended spanner to another dowel, same process, and used that to grip the nut, whilst tightening the screw. Once there was a bit of load on the nut, it held okay, whilst I really pulled it up.

Same process for the lower rivet, with the longer screws, you have to do the top screw first otherwise you can’t get access to get the nut on.

This sounds complicated and fiddley, but it only took about ten minutes, once I stopped thinking about it and got on with it.

Much easier to get everything assembled than I thought, given you can’t actually see anything.

The screws are really secure and haven’t worked loose in over a year. If they did, I’m fairly sure I could use the same process to re-tighten them.

There is a moment of terror, when you drill out the old rivets, but this is easier to get back together than it sounds.

Wayne LN172

Slot Gasket Repairs

The Basics

The slot gasket is that piece of cloth or plastic which covers the bottom of the centreboard case. Without it, the Lightning becomes one of the wettest places known to man, as water fountains up into the cockpit as you sail along. If you go fast enough, it can hit you in the face, even. Once the gasket is damaged, not only will you have a bath, not a boat, it is pretty slow on a race course, too. New gasket can be bought from any good dinghy chandler. I went for Mylar, as it is the smoothest finish and pretty easy to work with. They will also sell glue to fix it with, though Thixofix also works. This job is most easily done if you take the centreboard out first. When you turn your Lightning over (prop her on something other than mud – as one soul found at the Nationals, removing soil from the cleats is a difficult job. The culprit sails a Supersofa now – what more needs saying?!) you will find that the slot gasket is either stuck straight to the hull, with no recess, or is in a recess in the hull and covered by plastic keelband. If you find the former, you can simply replace it using just the part of the instructions relating to getting the mylar slot gasket stuck on, and won’t have to worry about the recess, screw holes and the like.

If you find the recess, there are a couple of different ways about replacing the gasket. Firstly, you can keep the set up pretty much as is, just swapping the gasket for new. Secondly, you can fill the recess, put the gasket flush with the hull and throw the keelband away. Theoretically, this will give you a faster boat, as the water turbulence round the keelband may well be quite large. I’ll deal firstly with the straight replacement. This is the way I did my boat, as I’m a simple soul at heart, and not 100% convinced of the speed differences.


OK, so the boat is upside down. You’ll see 2 strips of plastic with some small The old stuff removed screws through it, holding down what I will assume is a very messy and broken slot gasket of some sort. Undo the screws, and put them somewhere safe – they roll off the hull and get lost in the grass otherwise! Remove the plastic keelband and put to one side. You can then peel off the current gasket. You may find it was glued with an Evostik type glue, or possibly with mastic, depending on whether the job has been done before. You will need to clean all this gunk off (Acetone works well, or glue remover – avoid petroleum based products, as they may stop new glue sticking properly).

Once the boat is clean, it is worth spending a moment inspecting the join between the hull and the centreboard case – this is a prime area for leaks, and one that is difficult to see normally. If your boat leaks and you think you can see a crack, it might be worth contacting the Lightning Forum for advice before carrying on!

Gluing it Down

Right, no cracks, good! Next, unwind the roll of Mylar gasket along the bottom of the boat, over the slot. If you bought 70mm wide gasket, it will be approx 10mm wider than the recess. lay it so it is down one edge and mark exactly where you need to trim it. My recess wasn’t the same width all the way down, so watch out! Using Marking out scissors, trim to width and length. While you’re about it, cut the semicircle to match the front end. You then need to tape the gasket firmly to a flat board. You can then mark the exact middle line of the gasket, fore and aft. Using a long straight edge and a sharp knife, cut the gasket, leaving a couple of inches uncut at the front end and a little less at the back. Then stick masking tape down the cut (on the outside) to hold it together. Fasten the gasket in place on the boat with a strip of masking tape, so you can flap it back against the hull beside the recess Paint a thin layer of glue onto the recess and onto the underside of the gasket. Follow the instructions on the glue as for waiting times. Once ready, carefully flap the gasket into place, removing bubbles as you go. Leave it for a while to be stuck firmly.


You should be able to see, though the Mylar, the old screw holes for the keel band. Using a spike of some sort (an awl, maybe) puncture the mylar at each screw hole. Lay the keelband back on and screw it down. You may find a surprisingly large gap between the edge of the keelband and the hull at the edge of the recess. I filled mine with sealent – you may think of a better way of filling it, or maybe decide that it isn’t a problem! And so to the method where you fill in the recess. The removal parts are all the same as before. Once the recess is clean, you will need to carefully fill the screw holes. The end result of the Progrip method Polyester filler (Plastic Padding is one brand) will do fine for this. Sand smooth after, and also sand the gloss off the gelcoat in the recess, as very little will stick to glossy gelcoat.

Recess Method

I’ve come across several methods of filling the recess. One person used strips of wood, but in an all glass boat this seems asking for unnecessary rot trouble. Another tried pure Plastic Padding, but this is too brittle. It may be possible that an epoxy filler would stay better. However, the best method I’ve heard of was done by Simon Hopkins on the boat in which he came 2nd at the Nationals.

This method involved using 2 strips of 3mm Progrip (the stuff used on the inside of trapeze boats to stop the crew sliding all over the place) cut to the exact size and shape of the recess. They can then be glued in using the same glue as sticks the gasket. You will find this leaves a perfect amount of room to fix your Mylar gasket and have it flush to the hull, The fixing of the gasket is the same as before, but as there is no recess, it may well be worth taping round the work area to stop the glue getting on the hull. The Mylar will stick well to the Progrip.

The Progrip Method

Is a very neat solution to getting rid of the hull recess, and you will certainly end up with a smoother hull. The disadvantage is that of having 2 layers of glue close to each other, with the possibility of it coming adrift. Simon was painstaking in his approach to the replacement, and has had no trouble at all. Whichever method you use, the job is pretty straightforward, but does involve preparation, reading the instructions on the glue (difficult for us men) and attention to detail.

Rupert Whelan

Hull Leaks

There are a couple of common places to look at if you have a small hull leak.

THE CENTERBOARD to deck case joint is a fairly common area on some older boats. It is not easy to effect a solid repair and you’ll find yourself working in the CB slot. The problem stems for the hull to deck joint opening a little, but it can be fixed. Take a look at the tab above for more details about the repair scheme for this issue.

THE MAST SOCKET sometimes wears and causes a small hole, where the mast turns in the socket. This is easy to fix and is best done as soon as you notice it, just a little filler or glass tape over the worn area

THE COCKPIT DRAIN HOLE. This is a new one reported recently and was fixed like this.

A piece of plastic pipe which was a good fit inside the hole and was cut it to fit top and bottom and glued it in place using flexible filler. Very simple and worth a look before you start anything more drastic!

TRANSOM DRAIN PLUG. Occasionally the drain plug in the transom causes a few problems although that is easily fixed with a new plug. Just remove the old plug and housing and fit a new one with a good amount of sealer.

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