Repair and Maintenance of a Drascombe Lugger

Replacing the Cast Iron Rudder Guides
(page 1 of 2)

This page describes a replacement method for the two square cast iron rudder guides, which on Sospiri, were showing signs of serious corrosion . The description concentrates on the lower guide, which had worked loose causing a general sloppiness of the rudder in use. As a consequence, the rudder axle was also starting to damage the GRP gelcoat on the inside of the Rudder Trunking.

New Luggers use the same system of metal guides but they are made of cast bronze instead of iron. The bronze guides are much superior in resisting corrosion and can be used as a replacement for the iron ones. They are available by mail order from Churchouse Boats.

The first (Mark 1) Luggers were fitted with long steel rudder guide plates, slotted for the blade of the rudder. These can also be replaced with the new bronze guides although some additional fitting and fairing-in is required.

What do the Guides Look Like?

The original lower cast iron rudder guide Original Cast Iron Rudder Guide

The two guides are identical apart from the number and position of the fixing holes. The photograph shows Sospiri's original cast iron, lower rudder guide. This shows severe corrosion. Note that it was held in place by two small stainless steel self tapping screws - one of which is shown in the photograph. The guide measures 75 mm (from top to bottom in the photo), by 67 mm (from left to right in the photograph), and is 10 mm thick.

(Click on image for larger view)

A new cast bronze rudder guide New Cast Bronze Rudder Guide

The replacement cast bronze guides, as supplied by Churchouse Boats, are the same size as the original cast iron guides apart from being thinner (7 mm instead of 10 mm). They are not pre-drilled with fixing holes as these may not correspond with the holes in the original guides, but depressions on one side of the casting show the approximate positions and act as a guide for drilling the holes. The guide measures 75 mm (from top to bottom in the photo), by 67 mm (from left to right in the photograph).

(Click on image for larger view)

How Easy is it to replace the Guides?

Replacing the upper rudder guide is very easy and simply involves unscrewing the four stainless steel screws securing the old guide to the teak rudder trunking and replacing it with the bronze guide. It should be noted that the new cast bronze guides are not pre-drilled, but depressions in the casting show approximately the correct positions and act as a guide for drilling the holes.

The real problem is the lower guide which is secured to the hull above the keel plank. The keel plank has to be removed or partially displaced to remove the old guide and fit the new one. The following sketch illustrates the problem.

Sketch showing position of the Rudder Guides Sketch section of aft end of the Lugger showing the position of the Rudder Guides

This sketch represents a cross-section through the aft end of the Lugger. The rudder trunk is shown with the upper rudder guide screwed on to the teak capping by means of four stainless steel screws. Beneath the trunk, the lower Rudder Guide is sandwiched in a square recess between the hull and the keel plank and secured by two stainless screws.

Note the position of the two bronze bolts and four bronze screws securing the keel plank to the hull. These have to be removed so the plank will drop down sufficiently to allow removal of the old guide and the refitting of the replacement.

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Sketch showing detail of how lower rudder guide is attached The Problem of the Lower Rudder Guide

This sketch shows in detail how the lower rudder guide is attached to the boat. The two small stainless steel self-tapping screws are only 0.75 inches long and are totally inadequate to hold the guide securely in place. This was why the guide had worked loose on Sospiri. The problem in replacing the guide is its position between the hull and the keel plank. It looks as if the only way of doing this is to remove the boat from the trailer, tilt the hull to one side, remove the plank and old guide, fit the new guide, refit the plank and then get the boat back on its trailer. However it is possible to replace the guide without removing the boat from the trailer.

(Click on image for larger view)

View of keel plank with rudder slot Rudder Slot and bottom Rudder Guide

Photograph taken from beneath the Lugger on its trailer showing the wooden Iroko keel plank (partially covered with residual antifoul paint). The rudder slot in the plank is clearly visible, and at the top, part of the rusty cast iron rudder guide is visible. It is easy to test if the rudder guide is still firmly attached by placing a finger through the slot in the keel plank and through the keyhole in the cast iron guide. Jiggle the finger against the edge of the guide to see if it is loose.

(Click on image for larger view)


Replacing the Lower Rudder Guide with the boat on the trailer

This method very much depends on the kind of trailer used with the Lugger. One of the (many) advantages of a 'Swinging Cradle' type trailer is that most of the bottom of the boat is un-obstructed apart from where it is resting on the keel rollers. The aft section of the keel plank is accessible and by partially unfastening this, it is possible to get sufficient access to remove and replace the lower rudder guide. The following sequence of photographs illustrate this.

Photo - Unbolting the keel plank Releasing the Keel Plank (1)

In this picture of the Lugger on its trailer, it can be seen that the keel plank is accessible from the end of the boat to the first keel roller which is just aft of centreplate slot. The slot for the rudder is clearly visible. The first securing bronze bolt is being removed.

Tip: Use a spanner to undo the nut before trying to use a screwdriver to unscrew the bolt from its hole. Once the nut has been removed use a screwdriver with as large a blade as possible to unscrew the bolt. Make sure the slot in the head of the bolt is clear of paint and debris. This will ensure the screwdriver blade gets a good grip in the slot.

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Photograph of screws and bolt securing the keel-plank aft of the centreboard case Releasing the Keel Plank (2)

After removing the 1st bronze bolt, deal with the other keel plank fixings which are located aft of the centreplate case, beneath the floorboards. The fixings, shown in the photograph, consist of a second bronze bolt (which passes through the keel-plank, the hull and the base of the rear locker moulding), and three bronze wood screws passing through the hull and into the keel plank. Clean out the slots in the top of the screws (and the bolts) to ensure that the screwdriver blade gets a good grip and doesn't slip and damage the slot. If the slot gets damaged then the screwdriver blade is more likely to slip and extraction becomes harder.

Note that the arrangement of bolts and screws may not be exactly as shown on this Lugger.

(Click on image for larger view)

Easing and wedging the keel plank down Releasing the Keel Plank (3)

After removing the keel plank fixings aft of the centreplate, it should be possible to, very gently, ease the keel plank down, about 8-9 cm maximum, measured at the aft end, and wedge it in place with a piece of timber (a scrap piece of 44 mm square softwood is shown in the photograph). Take care not to ease the plank down too far so that it snaps!!

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Photo of loose guide ready for removal Removing the old iron Rudder Guide

Photograph beneath Sospiri showing the keel plank eased down. The loose guide has dropped out of its square recess in the hull and is resting on the top of the plank. One of the retaining stainless steel screws dropped out and the other one was missing completely!

This completes the removal process.

(Click on image for larger view)

Click on link below to continue

[Forward to page 2, Fitting the Replacement Bronze Guide]