Case study: Steel Narrowboat

The following defects were found on a Steel Narrowboat.

• The ‘V’ bottom hull has been subject to scouring by the bottom of the canal, this has resulted in thinning of the outer edges of the bottom plates. (The accompanying Ultrasonic Thickness Test Report detailed the areas affected and showed that the original 6mm plate had thinned down to between 2mm and 3mm over large areas)
• Away from the areas of the bottom plate worst affected by the scouring action, corrosion has resulted in pitting over much of the surface. The pits were found to have a maximum depth of 2mm in plate shown by ultrasonic thickness testing to be in places as thin as 3.9mm, leaving only 1.9mm thickness at the pit bottoms in the worst affected areas
• At the bow on both the port and starboard sides of the boat the side plating is dented
• The blades of the 14 inch propeller are badly distorted
• The shaft bearing is worn allowing significant movement of the shaft within the bearing
• The rudder post bearing on the skeg has worn and corroded
• The top of the rudder blade is bent to starboard
• The forward end of the coachroof on both the port and starboard side has suffered contact damage and is distorted On the starboard side the adjoining bridge guard is bent and at its forward end the deck around the mounting is indented
• The bottom of the aft door is weakened by rot and the bottom panel where it has been repaired is loose
• There is no provision for drainage in the bow locker, water lying in the locker is almost up to the level of the fresh water tank breather and could contaminate the fresh water supply
• The forward end of the coachroof grab rails have suffered contact damage, on the starboard side the rail is cracked
• The weld attaching the foremost floor (transverse bottom frame) to the hull has broken
• The port side edge of the plywood flooring (sole boards) along the length of the boat, where visible, can be seen to have weakened by rot, a spike easily penetrates the wood in all areas tested
• The sole below and adjacent to the shower cabinet is severely weakened by rot and part of it has been removed. A steel plate has been inserted to support the shower tray as a temporary measure
• The sole below the companionway has rotted and a new section of board has been inserted
• In other areas particularly in the galley the flooring is weak or unsupported underfoot
• Given the amount of rot already noted without lifting the fixed down carpeting, it is likely that large areas of the flooring will require replacement and it is probable that full replacement is the best option. Whatever the extent of the replacement, removal of the shower and toilet (heads) compartments and most of the furniture will be necessary
• The sealant around the shower cabinet is compromised, the pine sidelining is rotted and holed and the surrounding woodwork is loose and weakened by rot
• The frame to the forward doors is loose and partly rotted
• The vessels batteries are mounted in a tray over the keel cooler, the top of the keel cooler in this area has corroded
• The copper supply and return fuel lines running to the tank have been crushed
• The float switch operating the electric bilge pump is jammed in the on position and the pump runs continuously
• Plus a number of less serious defects

Case Studies

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• Vessel 1: GRP Yacht
• Vessel 2: Steel Narrowboat
• Vessel 3: GRP Motor Yacht

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