Call us on:
+44 (0)1425 617722

Technical Advice



Modifying Sections
Using Adhesives
Fitting Instructions for Fenders
Window Seals
Locker & Hatch Seals
Conversion Tables


If we are unable to supply a product that is exactly the size you require try adapting one of our existing products by using the following methods.


Laminate solid neoprene strip onto (A) the sides and/or bottom of the channel to increase its overall dimensions or insert into the gap (B) in the 'U' to decrease its internal dimensions.


Laminate solid neoprene strip onto the base (A) to increase its height or onto its flange (B) to increase the length of the flange.



To make a hatch seal that is soft enough to compress but has a hardwearing skin, try laminating solid neoprene strip onto expanded neoprene strip using a contact adhesive (order code A139 or A262).



If the size that you require is not listed and we are unable to obtain it for you, try laminating two sections together.



When gluing rubber it is advised that you abraid it's surface first and then degrease it with a solvent. E.g.. Acetone, MEK, Toluene or Meths. (Not an oil based one like white spirit). Ensure that the other surface you are sticking to is dry, free of dust and grease free.

If using a contact adhesive, it is best to apply one coat of adhesive to each surface and allow it to dry fully. Then apply a second coat to each surface and when tacky press the two parts together.

If using a Silicone or Polyurethane sealant, apply plenty to the joint/surface and then smooth off with a wet finger or scraper. Allow at least 24 hours to cure.


 Thixofix (order code no.A139)

One 40cc tube covers approximately 0.12 square metres. Therefore you will need the following

6 metres of rubber strip up to 20 mm wide requires 1 tube.

6 metres of rubber strip up to 40 mm wide requires 2 tubes.

And so on.

Waterproof Contact Adhesive  (Order code A262)

One 1/4 litre tin has a coverage area of approx. half a square metre.

Polyurethane (order code no S136) and Silicone (order code nos. S137 & S138)

Joint size Metres per 310ml cartridge

3 x 5 mm (15 sq. mm) 20.7

5 x 5 mm (25 sq. mm) 12.4

10 x 5 mm (50 sq. mm) 6.2

10 x 10 mm (100 sq. mm) 3.1

15 x 10 mm (150 sq. mm) 2.1

20 x 10 mm (200 sq. mm) 1.6

25 x 10 mm (250 sq. mm) 1.2

Please note that the above figures are theoretical only.


Download fitting instructions for fenders


D Fender Fittings


  • Feed the fixing bar through the centre of the D.
  • Line up the fender with the side of the boat and with a lubricated drill bit, drill through the face of the D, fixing strip and gunnel.
  • Using self-tapping screws or bolts fasten the fendering every 150-200mm.
  • To plug the drill holes, cut enough plugging cord to touch the screw/bolt heads and secure in place with a polyurethane adhesive. Once the adhesive has set, trim the plug so that it is flush with the top of the fender.


U Fender Fittings


This type of fender normally locates onto a flange protruding from the side of the boat.

  • If you have a PVC fender it is recommended that you soften it first in boiling water.
  • Fasten the end of the fender at the transom by using self-tapping screws or rivets through the underneath of the profile and into the flange.
  • Pull the fender around the boat and secure onto the flange every 300-600mm. If you have to take it around a tight angle heat that specific area with a hot air gun or boiling water



This fender is normally supplied in lengths approx. 3.65 metres long.

  • With the end approx. 1.8 metres from the bow, line up the fender with the gunnel. Drill and secure with self-tapping screws or rivets every 225-300mm.
  • Pull the fender around the bow fastening as you go. Butt up the next length and fasten in the same manner. For tight bends it is advisable to put some wire in the corners of the internal grooves to prevent the fender collapsing and hindering the fitting of the insert.
  • Heat the PVC insert and start fitting at the transom. Once fitted do not trim the ends for 3-4 days to allow for shrinkage.
  • Trim and secure ends of insert with end caps or self-tapping screws.


Listed below are the most common types of seals used on boat windows.  Obviously some boat manufacturers like to have a design peculiar to them (these are not necessarily shown below). We would be pleased to try and source rubber sections for you or come up with an alternative product that will be suitable for your application. Please either send us a sample or a sketch of the section giving dimensions and material type that you require.



Claytonrite Window Rubbers Claytonrite type window rubber. The cabin side and glass fit into slots in the rubber section, which are held in place by means of a filler strip.
Order codes WS61 to WS71, dependent on size.


Download Claytonrite window rubber fitting instructions

The extruded rubber section has 3 recesses. One for the window, one for the panel and the third for a filler strip, which is used to lock the rubber seal against the window and the panel to ensure a good weatherproof fit. It is necessary to have the correct size of seal and this is can be determined from the window and panel thickness.

To remove the old window

Locate the ends of the filler strip and hook them out. Then remove the strip all of the way around. Push the window firmly on the middle and it should come out of the rubber quite easily. Be careful not to break the window, as you may need it for a template for a new one. Remove the rubber seal from the panel and clean the area where the seal has been.

Fitting the new seal

Fit the rubber seal around the aperture pushing it well into the corners to determine the length required. Cut the rubber approx. 25mm over length with good square joints to make a really tight butt joint. Remove the seal and apply a small bead of silicone sealant into the panel groove and then refit the rubber around the aperture, ensuring that the butt joint is at the top.

With the rubber in place apply a small bead of silicone into the window groove. Push the window into the rubber seal at the bottom. Using the glazing tool work the lip of the rubber over the edge of the window.

To fit the filler strip, feed it through the eye of the glazing tool and then work it into the channel in the rubber seal. Use plenty of lubricant to ease fitment. Start with the joint at the bottom (opposite that of the rubber section). Be careful not to stretch the filler strip as you go, otherwise it will shrink back at a later date. Cut the end with a few millimetres of overlap and push it into the groove so that it butts the other end with a tight joint.




Aluminium Frames

The window is located in a rubber 'U' shaped channel inside of an Aluminium channel, which is fixed to the boat. It is advisable to bed the glass and rubber in with Silicone.




Download refurbishing Aluminium framed windows help sheet


Over a period of time the rubber seals in window frames tend to deteriorate and start to let in water. The only option is to replace it with a new seal. Temporary repairs can be made using a silicone sealant, but these don't last very long.

The following procedures should be followed.

  • Remove all the fixing screws from the frame. This is normally a two-person job, as you need one at either end of the fixing screws.
  • Carefully remove the window frame from the aperture making sure that you do not apply pressure to the frame and bend it. If the frame has been bonded in place with mastic, use a flat bladed scraper and ease it around the joint until the old mastic gives way.
  • The first thing to do is to clean up the old frame and rid it of all the old sealant. Avoid using sharp scrapers as these can damage the Aluminium.
  • The frame is normally made up from sections. At each joint remove the screws that hold the joining strip in place. Carefully tap a thin flat scraper blade, or similar into the joint, taking care not to damage the frame. Repeat this on each joint gradually opening up the frame until it is separated. Remove the seal and window.
  • Due to the marine environment it is advisable to soak all items in a bath of fresh water for a couple of hours. This will help loosen and dissolve any residue salt deposits. After the parts are dry more cleaning is required on the frame.
  • The next job is to check the condition of the window and seal. Most windows now days are made from Perspex. This is an excellent material but does detoriate over a long period of time. If you wish to replace it draw round it onto brown paper and send it to us for a quotation. It is a false economy to use an old seal and it is always advisable to replace it. To determine the correct size of seal you require three main dimensions are needed.

Glass/Perspex thickness

Internal width of channel

Internal depth of channel

If you are unable to locate the exact size in our catalogue, you can either modify one of our existing seals, or contact us with your requirements and we will try and source it for you.

Many seals used in old windows are no longer available and modern day equivalents have to be used.

  • Cut the new seal to length and apply a small bead of marine grade high modulus silicone sealant inside the rubber. Place the seal around the glass/Perspex. Now apply a small bead of silicone sealant into the bottom of the Aluminium frame. Carefully place the window and seal into the frame and pull all bits together until they are in the correct position. (You may require the use of clamps to pull the frame together). Now replace the screws into the joining strips.
  • To ensure that you have a watertight window it is advisable to apply a fillet of silicone around the top edge of the seal and frame. Mask off the frame and the window leaving about a 6mm gap. Apply the silicone and then smooth it off using a blunt instrument or wet finger. Carefully remove the masking tape whilst the silicone is wet.
  • When refitting the completed window into the boat you will require a seal to go between the frame and the cabin side. The best material to use is a closed cell expanded neoprene, about 3mm thick and slightly wider than the flange. (This can be trimmed off when the window is fully fitted). Apply this to the frame and pre drill the boltholes. Just before fitting the window to the boat smear a small amount of silicone sealant onto the top face of the seal. This will accommodate any minor imperfections and stop any leaks. Fit the screws and tighten up. Carefully trim the expanded neoprene around the edge of the frame using a sharp knife, and wipe away any excess sealant.



Over a period of time the seals in sliding windows tend to wear and deteriorate. Old windows used to use either a felt or webbing material, but these have now been replaced with a velvet-covered rubber. There are two main types: a preformed U shape, or a flat strip that bends to fit inside a channel.

  • Dismantle and clean the windows as above. Measure you frame and glass/Perspex to determine the correct size of seal. You may have to modify one of the seals to fit the channel correctly. (For example put a strip of neoprene under it or to one side to increase its height or width).
  • Apply a small bead of marine grade silicone sealant into the bottom of the channel and press the seal into place. Replace the glass/Perspex and reassemble the frame.
  • Refit the frame into the boat as above.



A rubber sealing strip is compressed between the cabin side and window. Suitable products are: -

Solid neoprene - order codes 29 to 40, dependent on size.

Expanded neoprene (plain or adhesive backed) - order codes 1 to 28, dependent on size.

1/2 round expanded neoprene - order codes 88 to 94, dependent on size. It is always advisable to smear clear Silicone onto the faces of the above material. This will take out any imperfections in the cabin side and also help to keep the gasket in place.

It is also advisable to make pilot holes in the seal for the screws. This will help prevent the seal from being damaged when the screws are being tightened.


Note: -  We also recommend the use of a sealant (order codes 136 to 138) under the heads of fixing bolts to help prevent water penetration.


Listed are four alternative designs, which in the majority of cases provide watertight seals. Please bear in mind the following factors when choosing the design which best suits your application.

Listed are four alternative designs, which in the majority of cases provide watertight seals. Please bear in mind the following factors when choosing the design which best suits your application.

A. Trueness of hatch to hatch aperture and deck.

B. Sealing surface e.g. Knife edge or flat.

C. Size of seal which is usually stipulated by size of gap. (The seal can often be modified or tapered to allow for any inconsistency in the gap).

D. Seal should compress by approximately 20% to provide a watertight seal. (This also helps prevent the seal from being over compressed and damaged).

E. The weight of the hatch and the number of fixings holding down the hatch. (The heavier it is, or the greater the number of fixings there are, then the larger the seal can be).



Expanded neoprene (closed cell i.e. does not absorb or transmit water.) Order code no. 1 to 28, dependent on size. Alternatively, half round sponge cord order code no. 88 to 94, dependent on size.



'P' section or 'tadpole' section. Order code no. P41 to P45, dependent on size.



'P' section, order code no. P42 or P43, dependent on size.

'B' section, order code no. RFB103.

The 'P' section locates into the centre of the hollow 'B' section.




Edging seal, order code no. ETS58 or ETS59.

The seal can also be fitted onto the hatch or locker lid.

Please note that there are many different styles of hatches. The above drawings have been simplified to clarify the seal designs. Seals can either be fitted to the hatch, deck or both. Generally it is better to fit it to the hatch, as it will help prevent it from being damaged or dislodged.


1 Bar = 14.5 psi
1 Foot = 0.3048 Metres
1 Metre = 3.281 Feet
1 Yard = 0.9144 Metres
1 Sq. ft = .0929 Sq. Metre
1 Sq. Mtr = 10.76 Sq. Foot