[PSUBS-MAILIST] Stability & Buoyancy

[Jon Wallace]

Excellent point and great photo to illustrate it.  I notice that the 
sail on Nutyco's Aquarius is completely vacant aft of the hatch to 
quickly release trapped water and of course doubles to provide easy 
access for entry.  Also the deck/ballast is high (at the hatch 
thru-hull) and very wide providing excellent stability.


On 11/30/2013 5:51 AM, MerlinSub at t-online.de wrote:
> E-Mail Software 6.0 Hi Alan,
>
> additional the sub can dynamic unstable during surfacing.
>
> There is a lot of water in the free flooding open sail.
> If you surface fast and with to small opening in the
> bottom of the free flooding sail the extra weight can
> move the CG so high that the sub tends to get heavy
> side angles during surfacing until the water rush out.
>
> The picture 8382a shows the higher waterlevel during surfacing
> in the sail and the MBT sadlle tanks still under water
> but for this sub the extra weight was not critical.
>
> But on a military one with there tons of
> water in the sail during a fast emergency surfacing
> it can be a problem.
>
> By the way Euronaut has no Kingston valve without any problem
> and a positve GB alltimes greater than 2".
> On dive station or surfaced.
> And great openings in the bottom of the sail.
>
> Boats without Kingston valve tends to lost some
> bouancy during rough sea. The tanks and the seastage
> work like a air pump and some water enter the tanks.
>
> On the otherside a boat with Kingston and a
> compressed air blow out system can blow away the
> tanks very fast if you forget to open the Kingstons
> during blowing the tanks or have a air leak
> in the in the pipe to the tanks.
>
> vbr Carsten

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