Lady Christina (F24) with cockpit rails. Bunschoten-Spakenburg, Friesland (2019)
This short article describes a suggested modification for those of us who like to grab hold of the chains from the pushpit to the aft stanchion for a bit of security. We used them a lot, but wished that they didn’t swing around like a slackline. If you can cope with the change from a removable to a semi-permanent fitting, then consider changing to a rigid tubular rail.
I made the change after a good friend came on board one evening, using the chain as a hand-hold to swing himself round the stanchion. His foot slipped, his leg plunged down between the quay and the boat and his alarmed pull on the chain bent the stanchion down. A similar technique is used to uproot small trees by pulling at right angles on the centre of a taught line- the tighter the line, the less force is required. It makes you think.
Making-you-think Physics interlude:
If the chain (in green) does not stretch, a force at right angles to it- say, 700N, or the weight of an adult- can be amplified by a factor of 10 along the chain. This is because the force applied at right angles to the chain can move much further than the force along the chain. This is a type of lever.
How to uproot a tree (or bend a stanchion)
In contrast, if the pushpit and stanchion are joined by a rigid tube, the two components share just the 700N right-angle force between them. The stanchion is much more likely to survive this; even more so if it has additional bracing.
There is no difficulty about sourcing stainless tubing from Ebay, with either a mirror or a brushed finish. The challenge is finding the fittings. Like most original Finesse parts, the dimensions are imperial. Both the pushpit and the stanchions are 1” diameter. A 25mm metric fitting will NOT slide onto a 1” stanchion! Fortunately, there is a ready source of 1” fittings in County Down, NI: see www.jclarkemarine.com/collections/deck-rail-fittings. John Clarke is a very helpful chap. Their parts are listed under Bimini fittings / canopy frame (Heavy duty). For the installation pictured in this article, you will need the parts pictured here, at a cost of about £36 per side (excluding postage).
Hinged jaw clamp (fits just below the pushpit shoulder)
Slide jaw clamp (fits on the stanchion at the appropriate height)
End cap, eye fitting (one at each end of a rail)
NB: The Allen bolts in these fittings are 6mm, not an imperial size.
