Title: The Keel
Jolly Roger - October 29, 2007 04:20 PM (GMT)
The Keel
The Evolution 26 has a vertically lifting cast iron keel weighing 800lbs.
There is a further 800lb of ballast (encapsulated lead punchings) bonded into the bilge.
The keel is raised and lowered either by a jockey winch on early models, or a hydraulic pump mechanism operated from the cockpit on the later models.
When the keel is lowered, it is bolted into place by a pair of struts which excerpt vertical pressure on the keel.
The keel is then rigid, and cannot be raised until the struts are removed. The boat is then effectively a fin-keeler and it has been known for boats to be dried out against a wall with the keel bolted down for anti-fouling (although I wouldn't like to chance it myself with a 20 year old boat!).
When the keel is raised, it does not protrude below the bottom of the boat, and the boat will therefore sit upright on the mud on a tidal mooring.
The Evolution has a tendency to swing around dramatically on a mooring in a gale if the keel is left up, which may be necessary if the mooring dries. This is due to the essentially flat bottom, and the centre of gravity being raised with the keel up. This could be a problem if other boats are moored very close. The other thing to watch on a swinging mooring is that as the Evolution will float before other boats (only needs just over 12" of water) so it may swing into other boats which are too close and have not yet floated.
The boat can be sailed with the keel in a semi raised position, which is useful for getting into a shallow harbour or over a bar. See the section on Rudders if you intend to sail in a very shallow area.
If the boat has struck something very hard with the keel down and possibly not locked it is likely that there will be some damage at the rear of the slot through which the keel protrudes. If you get a chance to look at the boat out of the water then this is an area that should certainly be inspected.
This boat has had an 'incident' and the owner has tried to fit a plate at the rear of the slot to prevent further damage. This has not worked as the keel has caught on the plate and tried to rip it off.
Inspect this area carefully.
If damage has occurred in this area, then the only way to deal with it is to remove the keel, cut away the damaged area and repair with epoxy.
The only way to remove the keel is to remove the keel capping bolts from inside the boat whilst the weight of the keel is supported from underneath. The keel bolts can then be re-inserted without the capping and attached to the lifting wire. The keel lifting mechanism can then be used to lower the keel to the ground.
If the threads in the top of the keel are damaged, they should be repaired using heli-coils before refitting.
by David Lincoln
The Evolution 26 has a vertically lifting cast iron keel weighing 800lbs.
There is a further 800lb of ballast (encapsulated lead punchings) bonded into the bilge.
The keel is raised and lowered either by a jockey winch on early models, or a hydraulic pump mechanism operated from the cockpit on the later models.
When the keel is lowered, it is bolted into place by a pair of struts which excerpt vertical pressure on the keel.
The keel is then rigid, and cannot be raised until the struts are removed. The boat is then effectively a fin-keeler and it has been known for boats to be dried out against a wall with the keel bolted down for anti-fouling (although I wouldn't like to chance it myself with a 20 year old boat!).
When the keel is raised, it does not protrude below the bottom of the boat, and the boat will therefore sit upright on the mud on a tidal mooring.
The Evolution has a tendency to swing around dramatically on a mooring in a gale if the keel is left up, which may be necessary if the mooring dries. This is due to the essentially flat bottom, and the centre of gravity being raised with the keel up. This could be a problem if other boats are moored very close. The other thing to watch on a swinging mooring is that as the Evolution will float before other boats (only needs just over 12" of water) so it may swing into other boats which are too close and have not yet floated.
The boat can be sailed with the keel in a semi raised position, which is useful for getting into a shallow harbour or over a bar. See the section on Rudders if you intend to sail in a very shallow area.
If the boat has struck something very hard with the keel down and possibly not locked it is likely that there will be some damage at the rear of the slot through which the keel protrudes. If you get a chance to look at the boat out of the water then this is an area that should certainly be inspected.
This boat has had an 'incident' and the owner has tried to fit a plate at the rear of the slot to prevent further damage. This has not worked as the keel has caught on the plate and tried to rip it off.
Inspect this area carefully.
If damage has occurred in this area, then the only way to deal with it is to remove the keel, cut away the damaged area and repair with epoxy.
The only way to remove the keel is to remove the keel capping bolts from inside the boat whilst the weight of the keel is supported from underneath. The keel bolts can then be re-inserted without the capping and attached to the lifting wire. The keel lifting mechanism can then be used to lower the keel to the ground.
If the threads in the top of the keel are damaged, they should be repaired using heli-coils before refitting.
by David Lincoln