Brian,
Keep in mind that the strength in most I-beam or T-beam forms is not in the
webbing. Thus holes through that area do not significantly decrease the
strength of your overall system.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
As scarce as the truth is, the supply has always been in excess of the
demand.
-Josh Billings
_____________________________________________
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brian Cox
Sent: Saturday, February 14, 2009 9:55 AM
To: Personal_Submersibles@Psubs. Org
Subject: [PSUBS-MAILIST] riding the bubble
In my incredibly large ballast / support structure, the inside is made
up of ribs which are a part of the ferro-cement form and which give the
thing more over-all strenght. I've been fretting about this aspect of the
internal shape of this area because at the top the ribs are a place where
pockets of air can't freely slide out to where the vent valves will be (
I'll have a vent on each side) . So to eleviate this problem I was going to
put small 1" holes at the top of each rib ( you can see the plugs at the top
of the ribs in the photo). But now, in lew of the dissusion on the bubble
riding factor, I'm thinking that that may not be nessesary. For one thing I
don't like the idea of a hole right there because it will weaken the rib at
that point, though I think there is enough steel to handle a hole at that
point.
http://www.frappr.com/?a=viewphoto&id=759383&pid=10308219
Brian
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