-----Original Message-----
From: Sean T. Stevenson <cast55@telus.net>
To: personal_submersibles <personal_submersibles@psubs.org>
Sent: Mon, May 28, 2012 12:30 pm
Subject: Re: [PSUBS-MAILIST] Holes In Ribs?
Just as an aside - on the ROV projects I have worked on, I always
secured piping by making UHMW brackets drilled for the pipe diameter and
then split, with half secured to the structure and half free, secured
with screws into helicoils in the base pieces. This allows for thermal
/ pressure expansion and contraction, and eliminates corrosion worries,
as well as damping vibrations to keep noise down.
-Sean
On 2012-05-28 09:18, Sean T. Stevenson wrote:
> This may seem a bit counter-intuitive, but the best place to drill holes
> in stiffeners, if one must, is actually through the stiffener web.
> Stiffeners work by increasing the local moment of inertia in
> consideration of the stiffener plus an effective length of the shell to
> which it is welded. The outstand (stiffener flange) actually makes the
> greatest contribution to this moment, as compared to material within the
> web which is close to the neutral axis of the combined section. Small
> holes are unlikely to make a huge difference, but assuming you have a T
> shaped stiffener, is it possible to clamp to the flange without drilling
> at all?
>
> -Sean
>
>
> On 2012-05-28 02:49, James Frankland wrote:
>> Hi All,
>>
>> Am i ok to drill holes in my reinforcement ribs? They would be about
>> 8mm in the top part of the "T". Just a few here and there to hold pipes.
>>
>> I've finished most of the high pressure plumbing but i need to hold
>> the pipes down. I didnt really want to drill into the ribs as it
>> means more painting, but ive scraped the paint off in places while
>> working so i have to re-do bits anyway.
>>
>> The other options are to weld tabs on, or use some brackets of some
>> sort, but i think easiest is just to bolt through and re paint.
>>
>> Thanks
>> James
>
>
>
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