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R32 Cockpit Grating replacement

Posted: 6 Jan 2021 - By: Neil Parsloe

The cockpit grating on our Rival 32 Valerie was getting to the stage that every time we glued a bit
back together another bit came loose, so it was time for a completely new one. The cost and work
involved in recreating a direct replacement was too much, so here is my solution which I hope may give inspiration to others.

It is made of Iroko and I chose a 22mm thickness after speaking to Richard at Bamptons as it was
the most efficient planed all round thickness for them to supply in the 20 to 25mm thickness range.

The top slats, side frames and end frames are 40mm wide, the middle five underneath cross pieces are 30mm wide (no.1 is longest and no.5 shortest) and the two end cross pieces 35mm wide. The gaps between the slats are approximately 17mm. There is a cutting list at the end of this article that works for a 1977 R32.

I worked out the slat width and gaps by drawing round the old grating onto lining paper, trying out
various combinations of slat width and gap and selecting the combination that looked right. NB the ends of the cockpit are not exactly parallel and the sides are at slightly different angles to the ends, hence steps 5 to 7 being done in situ. 

Four cross pieces no.2 to no.5 are 21cm apart, with a bigger gap between no.1 and no.2 which are 53cm. This section goes over a raised hatch in the cockpit sole. 53cm is a bit wide so there is some slight flex in this section. I think, with these 40mm by 22mm slats, a spacing up to 30cm would be fine and rigid. The two end cross pieces are to support the end frame to slat joint and are not joined with dowels.

All other pieces are epoxied together with 6mm diameter 30mm long dowels, except no.5 cross
piece to the outermost full length slat as it is too narrow at this point to dowel. The dowels are
hidden as the holes are drilled only from the joining face side and not all the way through.

To ensure the alignment of dowel holes, I drilled one hole and then marked the second hole position using “dowel centre points” (just google this if you've not seen them). I will use the words
“dowelling” and “dowelled” for the process of drilling a dowel hole in the first piece of wood,
marking the second piece of wood with the dowel centre points, and drilling the second hole.

The order you join parts together is critical to allow all parts to be dowelled. The two outer slats on
each side, which are cut at an angle to join the frame edges, must be attached to the frame edges
before no.1 through no.4 cross pieces. Also, final fixing of the two end frames is the third last step.

Here are the steps I followed. The first seven steps need to be done with access to the boat to get an accurate fit.
1. Cut and shape the two 35mm wide end cross pieces to be a neat fit at each end across the
cockpit. These end pieces overlap 50% with the end frames and 50% with the top slats and
side frames, so their distance from the cockpit ends depends on the slope of the cockpit
sides. I curved the outside edges to fit the cockpit sole to side join as our cockpit sides slope.
With vertical sides their positioning could be about 17mm in from the ends of the cockpit.

2. Shape and fit the end frames to sit above these end cross pieces. Ensure they fit against the
end and side of the cockpit as closely as possible.

3. Position, cut to length, and shape if needed the five 25mm cross pieces.

4. With the seven cross pieces and the two end frames resting in place, trim the two side
frames to about 20mm longer than their finished length.

5. Place the side frames in position on the cross pieces and mark their inner edge on no.5 cross
piece. Now do the dowelling of the side frames to no.5 cross piece.

6. Next epoxy the side frames to no.5 cross piece. Do this in-situ in the cockpit to make sure
the angles are correct.

7. When dry, repeat step 5 to mark the inner edge of the side frames on the other four cross
pieces and two end cross pieces, and also the alignment of the side frames to the end frames.

The following steps can be down away from the boat:

NB In steps 8, 11 and 12 parts are not epoxied together which allows them to be repeatedly
taken apart and reassembled during the dowelling processes.

8. Using the marks from step 7, cut the side frames to length plus an extra 5mm at each end.
Align the end frames and side frames and do the dowelling, but do not epoxy them together
at this stage.

9. Now mark the positions of each slat (and gap) on both end frames and also mark the angled
cut across the two outer slats on each side, where they join the side frames.

10. The two outer slats on each side were then cut to shape, dowelled and epoxied to the side
frame, while aligning with previously markings on the wide end frame. The accurate cutting
of these slats is critical to the final look; a friend did this with a track saw for me.

11. Next, the four remaining cross pieces are dowelled to the side frames and the two outer slats
on each side, but again not epoxied in place.

12. Line up the five remaining full length slats with the marks on the end frames (step 9).
Dowel them to the five cross pieces, but again do not epoxy in place

13. Now epoxy together the parts dowelled in step 11. Then working from the outside towards
the middle (to allow easy clamping of all joints) epoxy the middle 5 slats to the five cross
pieces.

14. Using the marks made in step 7 the slats and side frames can all be cut to length.
For accuracy, as in step 10, a track saw was used to do this cut in one go which gave a
straight flat end to all the slats and side frames for the end frames to join to.

15. The end frames were then dowelled and epoxied to the slats and side frames. The holes in
the end frames were drilled first during the dowelling process.

16. Next epoxy the two 35mm wide end cross pieces in place. Dowels were not used for these
as there was too little overlap of these pieces to the slats and end frames above.

17. Lastly cut limber gaps in the bottom of the cross pieces to allow water to flow to the cockpit
drains. They were lined up with the gaps to give the slats the maximum support.

After this it's just a matter of sanding everything smooth, rounding edges etc. I have epoxy coated
the cross pieces as they will be damp for a lot of the time, and will use teak oil on the top slats and frames.

Wood cost £135 from Bamptons in Southampton. www.bamptons.co.uk NB their opening hours
and email address on the website are wrong. Email is now bamptons1@gmail.com.

Sizes in mm

2 of 1480x40 Side frames
7 of 1470*40  Full length slats (includes the second slat in from each side)
2 of 850*40    Half length slats (the first one in from the edge)
1 of 620x40    Wide end frame
1 of 420x40    Narrow end frame
1 of 620*35    Wide end cross piece
1 of 410*35    Narrow end cross piece
1 of 600*30    No1 cross pieces
1 of 520*30    No2 cross pieces
1 of 480*30    No3 cross pieces
1 of 450*30    No4 cross pieces
1 of 415*30    No5 cross pieces

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