Brian,
This disappeared down the electronic plughole and so I'll repeat it.
It would be very, very, unusual for any monohull of any size and particularly this type of vessel, not to have bilge keels. If you search on "bilge keels" in the Forum you will find various ideas on attachment. The one described below is only my method.
Bilge keels always follow the turn of the bilge and their outer edge is normally parallel to it. They should not protrude beyond the line of the ship's side or below the keel. That will give you some idea of sizes. For the lack of a GA drawing depicting the keels, I suggest that they would start somewhere between L/3 and L/4 from the forefoot and about the same from aft. If it looks right then it probably is.
Riveted ships employed an angle bar riveted to the hull with the actual bilge keel formed from a flat bulb plate lap-riveted to the angle. This made repair much easier.
Welded ships such as you are modelling, employ a flat plate edge-welded to the hull with a bulb plate lap welded to it. (See drawing)
The ends of the bilge keels are always tapered.
My method was to cut a slot in the hull and insert a piece of stiff card, temporarily held in place. The curve of the hull and thus the curve of the bilge keel can then be drawn on it. This shape was transferred to aluminium sheet allowing for the keel protruding within the hull to be cut vertically and bent over as tags. Once happy with the shape, slide it in place, bend over the tags and fill/glass it in place to retain it and restore the small loss of strength produced by the slot. The external look of the keel can be improved by applying flat strip and half-round to simulate the steel section. I wouldn't bother trying to simulate the lap weld attachment unless you really want to excel on detailing.
I hope this helps.
Barry M