Repair and Maintenance of a Drascombe Lugger
Fixing a loose centreplate axle (page 3 of 5)
Repairing the Centreplate casing
This page describes the second stage in fixing the
problem of the loose centreplate axle. Having removed the
centreplate and the old axle, the next stage is to repair
the enlarged hole and associated cracked GRP around the
area supporting the axle in the centreplate casing.
In summary this was tackled as follows:
- Remove the 'domed' areas of the centreplate casing
in the vicinity of the axle by sanding the GRP either
with a sanding block or preferably with a PowerFile.
- Prepare a jig to support the new axle by using a
softwood plank that is a fairly tight fit in the
centreplate slot in the bottom of the hull.
- Drill a 12 mm hole through the plank so that the
replacement axle (bolt) will pass through it.
- Position and clamp the wood in the centreplate
casing so that when the bolt is passed through the hole
in the wood it is in the correct position for
supporting the centreplate.
- Inject some thickened Epoxy resin around the bolt
on each side of the centreplate case and allow to cure.
- Remove the bolt and then the wood.
- Add additional strengthening to the centreplate
case around the axle holes.
- Replace the centreplate and pass the bolt through
one of the casing sides, the centreplate slot and the
other casing side.
- Tighten the nut against the side of the centreplate
casing using rubber washers to prevent leaking.
Step by Step Guide
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Step 1. Remove the axle 'bulges' on the sides of
the centreplate casing
This is best carried out either using a sanding
block with grade 60 Aluminium Oxide paper or else
by using a PowerFile
(Click on image for larger view)
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Preparing a wooden jig for supporting the new
axle
Select a plank of softwood which is a tight fit
through the bottom of the centreplate slot (at the
bottom of the centreplate case). For Sospiri
the plank was 17 mm thick about 4 feet long and 5"
in width. Drill a 12 mm diameter hole in the middle
of this making sure that the hole is drilled at
right angles to the surface of the wood. This hole
will support the new axle (bolt). The next step is
to ensure that Epoxy Resin will not bond to the
wood within the hole or on the flat surfaces
adjacent to the hole. This can be achieved by
painting the wood with PVA Emulsion (e.g. Evostik
Wood Glue), and by means of strips of adhesive
Parcel Tape. Neither of these plastics will make a
bond with Epoxy Resin.
(Click on image for larger view)
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Step 2. Position the wooden jig to support the
axle in the centreplate casing
Lower the wooden jig through the slot in the top of
the centreplate case and manouvre it so that the
hole for the bolt is in exactly the right position.
Then fix it in position with a G-Cramp.
(Click on image for larger view)
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Preparing a plastic sleeve for the bolt
To make sure that the Epoxy used for repairing the
centrecase does not bond with the bolt, use the
plastic parcel tape to make a 'tube' around the
bolt. This is easiest done by wrapping the tape
around the bolt sticky side outwards. After making
the tube dust it with ordinary household talcum
powder so it can be handled without sticking to the
skin of your fingers!
(Click on image for larger view)
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Step 3. Inserting the plastic 'tube' through the
jig
The 'tube' is then gently pushed through the axle
hole in the wooden jig so that there is an equal
amount of overlap on each side of the wood.
(Click on image for larger view)
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Step 4. Inserting the axle bolt into the plastic
'tube'.
The axle bolt is gently eased into the plastic
'tube'. This is shown by a diagram on the left and
two photographs on the right showing both sides of
the centreplate casing.
(Click on images for larger views)
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Step 5. Injecting thickened Epoxy around the
plastic 'tube'.
First of all the GRP surrounding the holes are
wetted out with unthickened Epoxy resin. This is
immediately followed by thickened Epoxy (Using 404
filler thickened to a mayonnaise consistency), and
best applied using a syringe. It is important not
to let the Epoxy come into contact with the
stainless steel bolt! Smooth off with a wooden or
plastic strip. Photos show the holes and bolt after
application of the thickened Epoxy.
(Click on images for larger views)
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Step 6. Removing the bolt and the wooden jig
After the Epoxy has cured (24 hours), it should be
easy to remove the bolt from the plastic tube and
then lever the wooden jig and lift it out of the
top of the centreplate casing.
The top right photo shows the arrangement after the
Epoxy has cured and before the removal of the bolt
and the jig. The top of the jig is protruding
through the top of the centreplate casing, held in
place with a G-cramp. At the bottom of the casing
the bolt can be seen within it's plastic sleeve
embedded in the thickened Epoxy.
The lower photograph shows the repaired casing
after removal of the bolt.
(Click on images for larger views)
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This completes the basic repair of the damaged
centreplate casing but it is a good idea to add
additional strengthening to both sides of the casing in
the area of the axle.
continued
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Introduction Extraction
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