Re: [PSUBS-MAILIST] Location of fore planes (was: Is the list very quiet lately?)

[Gregc02@ibm.net]

>Any idea why the Japanese WW2 "kairyu" had planes approximately
>amidships instead of at the bow?



>Mike




Midship or "fairwater" planes give you less of a "bow up" tendency during depth changes. 

On the WWII fleet boats, the usual practice was for the bow planes to control the depth and for 
the stern planes to control deck angle or bubble. That way the person on bow planes didn't have 
to worry about deck angle and could concentrate on depth control.
For most small depth changes or running at a constant depth, the deck angle was kept within a 
degree or two of level. For bigger or faster depth changes the diving officer could order larger up 
or down deck angles (as much as +/- 20 degrees, or more).
You'll notice that most of the post WWII subs have fairwater planes instead of bow planes.
Fairwater planes don't have as much effect on deck angle while controlling depth. The diving 
officer will still use deck angle but it's easier to control deck angle with the fairwater planes 
closer to the center of the boat and not trying to pull the bow up. I spent far more time on the 
planes of WWII era deisel boats, but if I remember correctly, we could use just the stern planes 
on the Alexander Hamilton (SSBN 617) for normal depth keeping, while using both fairwater and 
stern planes for larger depth changes. Plus we had "autopilot" for depth and course on the nuke; 
it was alot more work on the fleet boat.
Plus, you don't have to rig them in and out like we did the bow planes, the fairwater planes were 
high enough, and close enough to the centerline, that they would clear things like  piers and 
other boats that we moored alongside. The bow planes on the fleetboats needed to be rigged in 
and out because they protruded out from the sides at the waterline (on the surface) and would 
take alot of abuse on the surface, not to mention running into the pier. They did, however, make 
great swimming platforms at sea and there were a nice set of ladder holes cut in the 
superstructure to make it easier to climb back up to the deck.

http://www.usstorsk.org/

Note that in the current day pictures the Torsk is riding about 4 feet higher than she should 
because of empty tanks and the 252 tons of missing batteries. 

http://members.aol.com/~ssbn617ah/hamilton.htm

Hope this helps,

Greg Cotton