So, down to the making of the rudder and assembly for the Mary Stanford.....
Unlike the other two boats that have their rudders set into the deadwood of the Keel, this boat had the rudder hung onto a square section rudder bar which runs through a series of brackets on the stern of the boat, including a hefty bracket at the top, a "shoe" at the bottom and a mid spaced bracket to set the rudder at it's required possition on the rudder bar..
These brackets would be made from cast iron/steel on the real boats, and/or even bronze, but on the model the fittings are all made from cast white metal.
There are also two brackets attached to the rudder which have square shaped holes cast into them on a fore/aft axis so that two points/corners of the square run longitudinally with the boat, and the rudder bar is therefore set at this same "diamond" position......and as such the brackets on the rudder have no chance of slipping around the rudder bar because of the square shape!....quite a simple idea by the builders of these old boats, and also easy to replicate needing no screws, bolts or pins to hold the rudder from slipping.
I made the rudder as a seperate entity, and fitted the two white metal cast brackets and the strengtheners in 1.8mm ply and glued in place using epoxy for the w/m fittings and aliphatic resin for timber to timber. However before fitting the brakets I made sure that the square section bar slipped through the bracket holes freely and when O glued up I ran the bar through both brackets to make sure that they were glued in line and the bar freely able to move.
I started by fitting the top bracket ( the bottom shoe had already been fitted when doing the hull some months ago.
It was glued in place using epoxy and two steel pins to hold and secure it in place.
I then silver soldered a length of 5mm threded rod into one end of the square section bar, to take a top locking nut.
I next threaded a nut upto the joint between bar and threaded rod and locked in place using cyano.
I glued the slider bar which takes the pin from the servo to operate the rudder into place upto the top locking nut, using epoxy and then drilled through that asembly and inserted a 2mm nut and bolt to hold it all in place.Under this would be fitted a brass washer to aid movement and reduce friction.
I modified the bracket that is used on the Rother class lifeboat kit, and using a pin to hold it......fixed it to the stern post just below where to top bracket of the rudder will sit when the rudder is in it's correct position.
Next was to insert a brass rod up into the bottom of the square section rudder bar and secure it wit lots of cyano.
Now, ther is still no way to stop the whole rudder bar from lifting out of the shoe and flapping in the wind, so to make a tighter fit and impossible to lift upwards and out, I put two small diameter washers onto the bottom pin just before the square bare /round bar joint, and immediately under the top bracket I placed two brass washers onto the square rudder bar, and drilled imediately under them with a 1.0mm drill bit and inserted a split pin made from brass, wrapped it around the bar immediately under the washers, and this locked the whole assembly in place with a maximum of around 2mm up and down movement........Once it has all been painted the moving parts, metal to metal will be greased as a precaution.
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Topic: 3 Lifeboat builds, What goes into a model kit. (Read 322708 times)