retrofitting bilge keels

Madhatter

Madhatter

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Is this a job that could be done ?
The boat is an Itchen ferry long keeler 22 foot.
So the question is can a pair of bilge keels be fitted as moorings dry out and legs are worrying by their vulnerability.
 
Madhatter said:
Is this a job that could be done ?
The boat is an Itchen ferry long keeler 22 foot.
So the question is can a pair of bilge keels be fitted as moorings dry out and legs are worrying by their vulnerability.
Click to expand...

The simple answer is yes.
A clever solution might be to find another 22ft bilge keeler with bilge keels that look as if they might fit, and see if you can take a mould from them.
You will need to strengthen and reinforce your hull in the affected areas.
You will need to make a pair of keels which will mate perfectly to your hull, and have the strength to resist grounding.
You will need to ensure they are fitted perfectly in line with current keel so it does not turn in or out when sailing.
You will need to construct the bilge keels from the mould and devise an attachment system of bolts.
Once fitted you will need to fair them in and seal.

Once fitted you will find that you have increased the hydrodynamic drag, which will slow the boat.
For insurance, you may need to have a survey.
You may also find it unsellable.

You need to have a rethink. Probably based around selling an unsuitable boat, and buying a more suitable one.
Sorry if this sounds like bad news.
 
Done it - twice, for same reason as OP, drying moorings being all that was available.

The first time I fabricated shaped wooden keels. These slowed the boat down considerably, and i replaced them with steel plates which gave an extra .7 knot of speed.

The difficult bit is engineering sufficient strength in to the hull to take the new load, and again that is because there is usually furniture and bulkheads in the way. Generally speaking the best way is to build floors in that carry the load across the main keel, and find some way of fastenbing them to the main keel, so that the load is transferred to it. Remember too that bilge plates cvan be subject to quite high twisting or sideways loads if the boat is dragged sideways across the bottom as it lifts to the incoming tide so they need to be strongly fastened.

If it is difficult to transfer the load to the main keel, it can be possible to build in extra ribs. Other systems carry the load out fore and aft, but you need to be sure the is sufficiewnt stiffening to take lateral loading as well.

Setting them up in line with thge main keel is dead easy.

If using steel plates go for at least 3mm steel plate. Top flange needs to be between 75 -100mm each side to spread the load. Make a template out of hardboard to get the profile of the hull, flanges and the new keels then take it to a Blacksmith to have it made up. The main cost will be the steel plate.

Its often worth having a 50mm flange along the bottom of the plate to stop it sinking in to soft sand.
 
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Thank you all for your replies.:D
The Itchen ferry seems to tick all my box's for my long-term requirements :-
Price
draft
headroom
beam
sea toilet
reasonable galley
traditional styling
length
single handed sailing

mooring costs

bilge keels needed unless someone can convince me that legs will do the job.
This boat will be lived on for 2 to 3 months for 2 adults on the French canals and other trips, at other times will be moored in a drying harbour that does not bode well in an easterly blow ( Bristol Channel ).
I will have another smaller boat to play with between times.
 
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If your mooring is fore and aft on firm ground then legs are fine. Go to any small harbour or estuary in France and you will see plenty of long keel boats with legs. Bilge keels will ruin what performance under sail that you have an difficult to retrofit in a secure manner.

Don't do a cheapskate on the legs. Either make substantial shaped wood legs, or better still buy a set of Yacht Legs which have the advantage of being capable of disassembly when not in use.
 
A good few years ago I fitted bilge keels to a Macwester Rowan 22. I guess a similar boat to the Itchen Ferry.
I made them from 10mm plate cut by the local blacksmith. About 2'6" deep and 3'6" long. A flange about 6" wide at the top. I made a fore and aft template of the hull shape from thinnish plywood and had the plate cut to this. Top flange was hammered to shape by me.
Local engineer welded them up, and Scottish Galvanisers in Glasgow did the galvanising while I waited.
Inside the boat was reinforced with 3/4" marine ply glassed in. Keels thru bolted with 10 x 12mm stainless bolts nuts and washers.
Hull was faired with that glass reinforced filler stuff to fix minor imperfections, the bilge keel flanges covered with kling film and bolted up before the filler had gone off. Bilge keels removed and hull tidied up and then refixed bedded on one part polysulphide (Arbokol 1000 if I remember correctly.
Front of the bilge keels lined up with the point where the slope of the main keel met the ground, though probably not on the Itchen.
Keels were about 2" shallower than the Main long keel.

Total cost about £200.
My mooring was fore and aft, firmish sand/mud slight slope. Half tide.
No problems in the 5 years that I had the boat.. I never did trust the legs that she was on before the conversion.
Dave
 
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My hull is much like yours, I use legs everyday. Wood legs profiled to the hull are easily made, but you need the bolt to be low down, and that means access inside, two people to fit, and a bung for the hole.
 
I've got the Itchen ferry 25'. Same boat as yours but with bigger cockpit. I havent had her in the water yet but I'm not expecting sparkling performance with that full keel and plumb bow. I would imagine sticking another couple of keels on wont help either ;)
 
I had an Itchen ferry 22' a few years back , the best boat I ever had to date even better than the folkboat . She was cutter rigged and had reasonable speed . Funnily enough I dont remember if she had bilge plates. I kept her on a deep swinging mooring. Not much help to you, only wanted to concur with yourt admiration of the boat.
 
A bloke at my club added bilge plates to his hilliard (centre plate), so it would sit level on the mud during low tide. (which it does). It seemed (for him!) to be a fairly simple operation. He measured a few distances and had 2 keels made. He then atached them to a piece of hardwood (deadwood?), which was then fastened to the keel and the whole bit was then fitted.

I think he spent more time measuring the boat up, than it took him to put the keels on.

He spent load of time drawing various lines all over the boat - where certain lines crossed was where the keels were placed, drilled and attached. That was about 6/7 years ago and no complaints since. That boat has sat out during winters too!

Any pics of the hull profile?

Regards

Carl
 
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