[PSUBS-MAILIST] cold weather effect on ports

[vbra676539 at aol.com]

Sean,


Originally Perry used plain old neoprene o-rings, and then they sent PC-8 to Alaska for a walrus-through-the-ice-off-an-icebreaker mission. The o-rings compressed at depth but would not expand fast enough on surfacing due to the cold. The primary problem was hatch, main viewport and battery pods. Somebody had to scramble up a set of red rubber jobs with low-temp capabilities, then the boys had to tear the sub partly down to install them--on deck under a tarp, of course. Great fun. Not!!! Afterwards, we went back to neoprene with, one assumes, a different temp rating and never really had another problem. Well, okay, there was that other time.....


Vance



-----Original Message-----
From: Sean T. Stevenson <cast55 at telus.net>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Mon, Feb 10, 2014 2:49 pm
Subject: Re: [PSUBS-MAILIST] cold weather effect on ports



One presumes that there could potentially be an issue with either thermal shock to the acrylic window, or with o-ring compliance when taking a sub at thermal equilibrium on a frigid deck (-30° C) and immersing it in seawater at ~0° C.  It takes some time for both acrylic and elastomers to warm up - they are poor conductors of heat.  Don't the o-rings stiffen in the cold?
Sean




  <MerlinSub at t-online.de> wrote:
Hi Hank,
 
the limit according to GL is -18 celius degree 
- a temp seawater can not reach. 

The max temp to GL is 66degree.

In general colder is better for the pressure resistant of the windows (acryl). 

vbr Carsten
 

"hank pronk" <hanker_20032000 at yahoo.ca> schrieb:

Is there an adverse effect from cold temperatures on ports. I hear about cold weather dives in the North Sea etc.
When isit to cold for ports if ever?
Hank

 



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