Southerly Swing Keel

We are frequently asked about the variable draft swing keel system fitted to the Southerly 42 and Southerly 48 yachts, so we hope the following is an informative walkthrough of the installation process and answers some of the common questions and misconceptions.

Southerly 48 Keel

Does it rattle?

No! It’s not a lightweight plate but a very heavy cast iron keel, its set in a huge cast iron grounding plate, with a very substantial hinge pin, think about Victorian engineering! So it doesn’t move about or rattle either when fully up, down or anywhere in between. Here’s a picture of the Southerly 48 keel assembly that weighs in at 6,120kg. (3990kg for the grounding plate and 2130kg for the keel)

Does the Keel need maintenance?

Everything needs some maintenance, antifouling aside most keels seem to be refurbished after about 20-30 years requiring them to be dropped, in between times regular fluid level checks, annual inspection of the hydraulic system and 5 yearly pennant changes are all that should be required.

What about performance?

The reason the Southerly keel is so desirable is that it is very performance enhancing when compared to a fixed keel. It would be very inconvenient to have a cruising yacht with such a deep draught that is fixed, but the benefit of this is that combined with twin rudders and a narrow sheeting angle on the self tacking jib. A Southerly goes upwind really well with absolutely minimal leeway, and rudder angle (your autopilot will have less work too). Downwind the drag of that deep keel can be eliminated by raising the keel, which in turn moves all the weight aft raising the bow and she’s away! Because the keel swings it can be used to feel your way up a shallow channel, each time the boat slows to a gentle stop you can raise the keel and go a little further. So its not just that you can anchor inside the crowds, or beach her or jump the ques for locks and sills, it’s firstly a performance feature, as well as a tool for navigation, and shallow water.

Is it safe – what happens if you leave it up?

Southerlies will sail perfectly well with the keel raised completely, but leeway will increase substantially. You still have a massive ballast and form stability that will control heel angle so there is no risk in this. In extreme conditions, the keel can be locked fully raised which arguably is safer since there is no longer a keel for the yacht to trip over, also she is far less likely to broach. Should a Southerly hit the bottom or a rock at speed the keel will swing up absorbing the impact that might otherwise cause damage to the keel bolts or hull mouldings.

Can I beach it like a Bilge keel boat?

The keel structure is attached to the hull via a grounding plate of solid cast iron, usually about 2/3rds the weight of total weight of the assembly. This is designed to carry the weight of the entire yacht which does not then require any further support. Therefore beached on a level surface of sand or mud no harm will come to the yacht, it’s as well though to check where you intend to go to ensure the surface is suitable. The layup of the keel housing and hull around the grounding plate is enormous, and there are as many as 45 keel bolts holding the assembly in place. Its designed to be grounded without damage, and it is normal when ashore to just place the boat on sleepers under the grounding plate, with some props or preferably a cradle to stop movement in winds etc.

Leave a Reply

%d bloggers like this:
search previous next tag category expand menu location phone mail time cart zoom edit close