The Mast and Funnel Question
These memoranda on The Mast and Funnel Question are taken from copies contained in the Ship's Cover for the Lion class battle cruiser.
The Mast and Funnel Question.
Notes of a Conference on 29th March 1912.
First Sea Lord.
Second Sea Lord.
Captain Craig, H.M.S. "Orion".
The "mast and funnel" question has arisen in connection with the design of certain ships of the "Dreadnought" type in which the mast supporting the control top is immediately abaft the foremost funnel.
Nature of Defects -
The following is a summary of the defects of the "Lion" as originally designed :-
(1) The top control position is untenable when the forward boilers are alight.
(2) Bridges are too close to the top of spotting tower & in consequence the view is shut out when the ship rolls 5° or more.
(3) Heat & fumes from the funnel render upper bridge uninhabitable & make it difficult to use manoeuvring compass.
(4) The manoeuvring compass is unreliable owing to proximity of funnel.
(5) Flags and halliards are liable to be burnt.
Ships affected -
In the design of the armoured ships of the 1911-12 programme it has been approved to abolish the control top, to alter the relative position of mast & funnel & to make the conning tower the main steering position for peace & war. A similar arrangement has been approved for the 5 ships of the 1910-1911 programme - "King George V", "Centurion", "Ajax", "Audacious", "Queen Mary" - at an estimated extra cost of approximately £20,000 per vessel.
The remaining ships affected are those shown in the attached sheet A, viz:- Cruisers - "Lion" & "Princess Royal" - Battleships - 2 "Colossus" & 4 "Orion" class.
Alterations to the "Lion" & "Princess Royal" have already been approved, & are being carried out. It has been decided to remove the present foremost mast, to shift the forward funnel aft & to replace the tripod mast by a single mast placed before the funnel. To provide bridges, for navigation & look-out purposes only, quite clear of the conning tower. To steer from the conning tower, thus assimilating the arrangements to those approved for "King George V" class. Estimated cost not less than £25,000. It is considered that the alterations to the "Lion" will be complete by 1st June except possibly that the armoured roof of the conning tower may be delayed by strikes. If so temporary arrangements will be made so as to have the ship ready by the first week in June.
From the foregoing it will be seen that the question now to be settled is whether any alterations are required in the 6 battleships of the "Colossus" & "Orion" classes.
The following points deserve notice :-
Effect of heat & fumes from forward funnel in rendering control top untenable.
This varies with the type of ship.
(1) Yarrow boilers can be forced more than Babcock & Wilcox & produce greater heat. More trouble may be expected for this reason in the "Lion", "Princess Royal", "Monarch" & "Hercules" than in other ships.
(2) The more boilers served & consequently greater area of funnel, the more heat produced. It appears probable that this factor was not sufficiently taken into account of when the principle of mast behind funnel which had been approved for "Dreadnought" was applied to some of the later ships developing much greater horsepower. The conditions in "Orion" class are in close resemblance to "Dreadnought" & there is at present no evidence to prove that the control position aloft would be untenable under war conditions.
(3) The third point to notice is the vertical distance of the control top from the funnel.
It would appear from Table A that heat interference might have been expected to be greater in "Lion" & "Princess Royal" than in the battleships; & that of the latter "Monarch" & "Hercules" are most likely to be defective.
Effect of smoke & gases from funnel in obscuring view from control top.
This is a different matter. It is to be noted that whenever the control top is above the funnel there must be a liability to interference under certain conditions of wind & speed whatever the relative position of mast & funnel. The only satisfactory remedy is to find a position below the funnel for the control.
The important fact that was brought to the notice of the Conference is that there is a distinct change in the general opinion of the Service afloat as to the ideal position for the control. It appears now to be accepted that interference by gases & smoke from funnels is greater than that from the smoke of the guns & that it is preferable to find a control position below the top of the funnel. It was pointed out that the Germans have never put the control above the upper story of the conning tower.
Action required -
In view of the considerations set forth above the Captain of the "Orion" was asked to say whether in his opinion it was worth while putting either "Orion" or "Monarch" into dockyard hands for possibly two or three months now with a view to immediate & extensive alteration such as had been approved for the other ships. His opinion was definitely in the negative. He personally preferred to put in a forward range-finder in B turret & was conducting experiments in the "Orion" with a view to gaining more experience.
General conclusion -
No further immediate extensive alterations are required beyond what is already approved.
Further experience is required to ascertain the best control position in "Hercules" & "Orion" classes.
Experiments are being carried out afloat in "Orion" & these should be pushed on.
The need for better control position to be borne in mind & action to be deferred until more experience has been obtained & a suitable opportunity occurs for making any dockyard alterations ultimately considered necessary.
Sd. J. S. Barnes.