Re bedding Keels
The iron keels on a Westerly Centaur splay outwards so that the leeward keel is vertical and the windward keel is acting as a counter weight whilst healed over sailing. This gives a better sailing performance compared to other bilge keelers with vertical keels but can put great loads on the keel to hull joints. Older Centaurs and other bilge keel Westerly yachts have to be strengthened inside the keel stubs to prevent flexing which results in cracking. The great flexing and bending forces incurred whilst sailing and whilst grounding when the tide goes out will eventually cause to hull to keel joints to break down.
The iron keel is butt jointed to the moulded in GRP keel stub and held in place by six stainless steel studs with large washers and nuts. Sealant is applied to the contact surfaces to prevent water leaks but this sealant will eventually dry up and break down. Most manufacturers would give an effective life of the sealant as being around twenty years. You can make a tempary repair by applying sealant to the outside but it will not last. The only way is to remove the keel, scrape away the sealant and replace it. It is important to prime the cleaned surfaces before fresh sealant can be applied as otherwise it will not stick.
The keel does not have to be removed completely and in fact it is only necessary to separate the hull and keel by a couple of inches to allow the joint to be cleaned primed and repacked. You will need to build a steel and timber support around the keel to lock the lower edges of the keels in position relative to each other and take the weight of the keel. It is also desireable to maintain the alignment of the keel bolts with the holes in the keel stubs.
You should then loosen the keel stud nuts and run a blade around the old sealant in the joint to help the keel and hull part. To lift the vessel either a crane can be used or two chain hoists attached to some form of substantial framework. The vessel can be lifteed one side at a time with the other side still supported on its keel. The keel will initially lift with the hull and the two will need to be parted preferably using with several (4)wooden wedges inserted into the hull keel joint. It might take some shifting and you will need to watch out for your feet and hands. When eventually parted block off the hull and make everything safe before you clean away the old sealant and prime the cast iron mating face.
Boatyards such as Retreat Boatyard on the Exe, Deacon's on the Hamble and Madge Marine in Chichester could do it for you for around Â£1,000.00 per keel.
The sealant that would have originally been used on your Westerly is called Marineseal 033. It comes in two packs of putty which have to be carefully mixed together by hand. It is designed to remain flexible for at least twenty years and can be bought from Marine Mastics Ltd who are based in Waterlooville close to where Westerly's were built.
Fosroc Nitoseal 600, a polysulphide sealant and primer MS2 are also recommended in Ref 1.
Tightening Down Keel Stub Nuts
The torque settings for stainless studs are
1.25 inch dia. 180 lb ft; 1.00 inch dia. 130 lb ft; 0.75 inch dia. 80 lb ft; 0.50 inch dia. 30 lb ft;
My advice is if it don't leak don't touch. If you do decide to have a go, then do one at a time,eg remove one and refit and tourque down before you tackle the next one, that way you stand less chance of disterbing the keel hull seal.
Marineseal 033 available here:
Trade Sealants Ltd (Marine Mastics.com) Tel: 02392 251321
Fosroc Construction Products â€“ 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 firstname.lastname@example.org
Ref 1 WOA Magazine Winter 2003 Pages 66-68 RE-BEDDING KEELS BY PAUL SHAVE AND DON SINCLAIR Ref 2 WOA N/L Winter 2000 Repairs and maintenance to cast iron keels, Paul Shave