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

["John Pier" <caribsub@coqui.net>]

to dive level with no trim angle
Herve Jaubert

----- Original Message -----
From: <Gregc02@ibm.net>
To: <personal_submersibles@psubs.org>
Sent: Thursday, February 08, 2001 3:16 PM
Subject: Re: [PSUBS-MAILIST] Location of fore planes (was: Is the list very
quiet lately?)


>
> >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
>
>