Difference between revisions of "Re bedding Keels"

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== Re-Bedding Keels by Paul Shave and Don Sinclair ==
In the Winter 2000 Newsletter information on maintenance and repair of cast iron keels was collated, principally articles by surveyor Ed Sawyer, advice from Tony Hillier, (Westerly Yacht Spares) and some other experience (1). Tony suggested the following method for re-bedding bilge keels and this article describes its use on Centaur Raggy Ray by owner Don Sinclair. The method is applicable to other bilge keel yachts and to fin keels with appropriate change to the method of lifting. Given the age profile of the fleet it will be of interest to many Westerly owners.
The keels of the Centaur weigh 1,400lbs each so that for the owner without commercial boatyard facilities the important thing is not to lose the alignment of the keel studs with their corresponding holes in the grp keel stubs.
To ensure retention of alignment the bottom of one keel is fixed relative to the other by, for example, utilising the channels of a trailer and wooden packing or by a steel or timber frame on the ground. The nuts are then removed from the studs of one keel and the boat jacked up or lifted on that side a couple of inches, tilting on the other keel. The studs remain in their holes, retaining alignment. Don actually left single nuts on the ends of some of the studs to guard against accident. When a sufficient gap has been opened up, and we found gentle force from inner and outer rows of oak wedges necessary, the old compound can be scraped out, mating faces cleaned, primed and the keel re-sealed. In theory, employing this method means that the keels are not lifted and much of the weight of the hull rests on the 'other' keel. In practice we found the keel lifted with the hull until it could be persuaded to separate from the keel stub, hence the wedges.
Unscrewing the nuts on the keel studs
Konsort owner Chris Wakefield did some web searching and came up with the product originally used by Westerly and its source. This was Thioflex 600 made by Fosroc, a two part polysulphide sealant. (Not Thiofix 600 as I had heard earlier.) Don contacted Fosroc and they supplied him with a newer single pack product Nitoseal 600 and recommended their primer MS2 for the cast iron faces (2). Fosroc has five branches UK wide, Don dealt with Baillieston, Glasgow who were very helpful.
Lifting one side of the keel
In the Upper Forth Boat Club yard boats are moved and stored on bogies running on railway lines. The keel channels of the bogey provided the means of locking the lower edges of the keels in position. In fact the keels were standing on plywood in the channels and it is doubtful if they would have moved but it seemed prudent to ensure they could not. The bogey is fitted with 'goal posts' on each side so that when submerged, as when recovering the boat, one knows where it is. The goal posts provided attachment points for two chain hoists to do the lifting. Nylon strops were used on the hull and wooden padding under the chains.
Applying force to separate the keel from the hull
In the absence of the bogey, scaffolding could have been used to locate the lower edges of the keels and provide attachment points for two chain hoists. This would have needed bracing as the keel will tend to lift with the hull. Initially the two chain hoists will take about half the weight of the boat, until the keel separates.
Fin keels can be re-sealed in the same way given a suitable means of raising the hull off the keel. Four chain hoists and framework to suspend them is one answer, for example scaffolding, either alone or built up on a boat cradle, trolley or trailer. However the same imperative of not losing the alignment of the keel studs with their holes applies. Given the equipment one can borrow, hire, buy new or secondhand, quite major tasks are within the capacity of the amateur.
Thirty plus years after the building of Raggy Ray the nuts on the studs were easily unscrewed using a large adjustable spanner, a tribute to Westerly quality, the studs being stainless steel. A few needed some grp covering chipping away with an old wood chisel. Don cleaned up the mating faces very thoroughly, whilst being careful not to nick the studs and perhaps initiate crack development. A variety of files, rasps, scrapers, a burr in an electric drill and silicon carbide paper were used.
Cleaning mating faces of keel and keel stubs
Applying Nitoseal 600 sealant
The cast iron was primed with Fosroc primer MS2 and the sealant applied with a gun supplied by Fosroc. One could I think use a conventional keel primer such as Blakes Keelprime or International Primocon with Thioflex 600 or Nitoseal 600 sealants but this should be checked with Fosroc. I don't know what, if any, primer was used by Westerly during building.
Cleaning mating faces of keel and keel stubs
The result looks very satisfactory and we shall try to report in a later issue on performance after immersion. Thanks are due to Fosroc for products and advice. We wish them well and hope that the association of Westerly with their Company continues.
Repairs and maintenance to cast iron keels, Paul Shave, WOA N/L Winter 2000.
Fosroc Construction Products - Company booklet and their web site: www.fosrocuk.com Fosroc Limited, Coleshill Road, Tamworth, Staffordshire, B78 3TL Telephone:            01827 262222      . FAX: 01827 262444. E-mail sales@fosrocuk.com
Information correct as of 1st December 2003

Revision as of 14:25, 30 November 2011