Paddleducks
Paddler Information => Research => Topic started by: Walter Snowdon on March 29, 2007, 08:46:25 PM
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Hi folks. The recent string on model paddle box "clogging" ( filling with water) made me go back to my books to look up some examples and remedies in full size.
In his booklet CARDIFF QUEEN Nick james quotes.... (Bristol Queen)..."With the doors of her paddle boxes open to reduce clogging effect of her small,under-ventilated boxes, she was good for 20 knots with a bit to spare." Looking at her sponsons there appeers to be no doors or ventilation in the sides, could they have been lift-up trap doors in the deck on TOP of her paddle boxes?.
Further on he states (of the CARDIFF QUEEN) ..."Her paddle wheels and boxes were of a better design than her sisters (BRISTOL QUEEN), for her wheels had seven curved steel floats as opposed to BRISTOL QUEENS eight, and there was much more space inside her paddle boxes. As a result of both these features, her boxes were less prone to clog with water than were those of BRISTOL QUEEN, whose engine I once saw stop completely for a couple of seconds, despite the regulator being three-quarters open". He also comments on the ammount of space in the boxes between the front and the back of the wheels .to sumarise this, the large space behind the wheels was fine when going ahead as the box could ventilate but when going astern the small space " made the ship shake and rattle when going full astern". (You cant compress water!).
So it appeers the full size ships had the same problems as models and as I have opined many times (Many times, many many times) smaller blades are more efficient (lift less water) and extra ventilation holes in the paddle boxes stop hydraulicking and causing instability. Gosh that was long winded.. hope it gives food for thought!. Walter.
By the way, if you can find a copy of Nick James booklet entitled CARDIFF QUEEN. THE ULTIMATE COASTAL PADDLE STEAMER. it makes an excellent read. It was published by Nick personaly in aid if the Paddle Steamer Preservation society and has no ISBN number. It is long out of print but pops up occasionaly on ebay. Thoroughly reccomended. walter