Re: [PSUBS-MAILIST] Boat operabilty without VBT

Thanks for the update Emile. I must have missed the upgrade to add the small VBT. With the pilot in a prone position, where do you locate this 10 liter VBT so that it coincides with the CG of the boat? Looking at the profile of the boat, it looks like it would be in a very uncomfortable position for the pilot. I looked again at the profile drawings of the boat as was originally built and the drawing that was made of a possible future upgrade. The 25 April 2002 drawing http://www.psubs.org/psub_pic/sgt_pepper.html that shows the addition of an external hard tank. Was this to be additional volume to the existing MBTs to give more freeboard or a clever way of added a hard VBT at the CG of the boat without taking up any valuable interior space? Are you and Carsten still considering this modification?

Good luck on your upcoming deep unmanned qualification test goes. Let us know how the test come out.

Cliff

----- Original Message ----
From: Emile van Essen <emile@airesearch.nl>
To: personal_submersibles@psubs.org
Sent: Sunday, February 10, 2008 11:03:14 AM
Subject: RE: [PSUBS-MAILIST] Boat operabilty without VBT

Cliff,

In fact the boat has a VBT. It is only 10 litres and that is a little bit to small.

The MBT’s are blown with the LP port.

The hatch opening was reducing the boats strength with 50%

Now I have made 2 support bars which are attached to the hatch and fit closely it the hatch opening.

Now see if the FE calculations are accurate…..

See if I can post some pictures to Moki.

Regards, Emile

Van: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] Namens Cliff Redus
Verzonden: zondag 10 februari 2008 2:25
Aan: personal_submersibles@psubs.org
Onderwerp: Re: [PSUBS-MAILIST] Boat operabilty without VBT

Carsten,

I while back you mentioned that Sgt. Pepper was just to small to have a VBT. Can you give us some of your operation experience with Sgt. Pepper just using the MBT for buoyancy control? Specifically:

When you are ascending or descending, how frequent do you have to adjust buoyancy back to neutral?
What is the ROB of the boat?
Does the fact that at depth the MBT is not completely filled with water cause any longitudinal stability problems:
What is your MBT air capacity and how long does it typically last?
Do you blow the MBT off the HP port of your first stage scuba regulator or do you use the LP side?
With the recent retrofit of the boat to from 300 to 600 what where the major changes?

Even though this boat has been around awhile, it is still a beautiful design.

Regards

Cliff

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