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Re: [PSUBS-MAILIST] Inner / Outer support ribs.



Dan,
 
   The point I never considered was using the rings to force the hull into roundness.  I can definately see where this would be easier when putting them on the inside as they could be pounded / hammered / tapped into place, spot welded, and then secured when all was well.  That answers another question in that the rings are to be pre made and not welded onto the pressure hull when building them.  In that way, the roundness of the rings could be made true before installing.  As for attaching things to the rings inside the hull, is it safe to drill 1/4" holes for bolts or is that comprimising the integretity of the ring too much ? ...or would welding mounting brackets to the rings and then drilling the holes be preferable ?
 
   On the K350, does the design just eliminate the ring where the tower is, the tower collar providing the strength in that area ?
 
   Thanks for making my mind up for me Dan.
 
Myles.
----- Original Message -----
From: Dan H.
Sent: Wednesday, November 09, 2005 9:10 PM
Subject: Re: [PSUBS-MAILIST] Inner / Outer support ribs.

Myles,
 
A K-350 has ribs spaced 12 inches apart, and at the ends where the hull tube meets the end caps, they are 10 inches apart leaving two inches of hull tube sticking past the last frames to weld the end caps to. 
 
True, the frame would be easier to apply to the outside of the hull, for convenience of working, but it's easier to spring the hull into better roundness when working from the inside.  No rolled tube is perfect round.   You have to work it as your installing the framing. 
 
Ribs on the outside give you more places for corrosion to attack, but do increase the inside room.  Ribs on the inside cramp the space in the sub, but are a convenient place to clamp things that you want to add later on, without welding on the finished sub hull.
 
Dan H. 
----- Original Message -----
From: Myles Hall
Sent: Wednesday, November 09, 2005 6:11 PM
Subject: [PSUBS-MAILIST] Inner / Outer support ribs.

I understand that support ribs offer the same strength increase whether they are on the inside or outside of the pressure hull.  As I am planning on adding fairing, I am also considering puting the ribs on the outside to free up interior space.  Is this a good idea ?  In other words, is it easier to install the ribs when they are on the outside ?  Are the ribs pre-made and then welded on or built right onto the pressure hull ?  I can't seem to figure out the ribs, how they are made, and the best way to install them.  My pressure hull is of a similar design as the K350 36" x 1/4 " x 8'.  I am considering a rib spacing of 18".
 
Myles.