Re: [PSUBS-MAILIST] through hull reinforcement

[Jon Wallace <jonw@psubs.org>]

Alan,

For steel, large hull penetrations require more steel than what was 
removed, hence the use of the word "reinforcement".  The design requires 
consideration of many factors including thickness of hull and nozzle.  
The areas of "build-up" that can be considered as reinforcement also 
fall within specific dimensions.  The lastest ASME rules also require 
that the reinforcement be "integral" to either the hull of nozzle, so it 
doesn't matter if that reinforcement is inside or outside the hull as 
long as it fits within the dimensional limitations of the allowable 
reinforcement area.

Unfortunately, I don't think any of the steel vessel rules for 
reinforcement can be applied to fiberglass.  Since you are planning on 
having your drawings analyzed by a composite engineer it probably 
doesn't matter what dimensions you put in your plans at this point.  You 
could always mark them as TBD (to be determined) and let the engineer 
spec them out.

Jon


Alan James wrote:
> Hi people,
> I need to design the reinforcement of the area around my hatch seat.
> I've read that with through hulls a general rule is you replace as 
> much material as has been removed
> at a 1/4 gradiant.
> My sub is small & is being made of fiberglass. At this stage I'm just 
> trying to get in the ballpark with
> my design calculations, as I intend to take take my drawings to a 
> composite engineer & get them
> analysed & corrected where necessary.
> Would the reinforcement be better on the inside of the hull, the 
> outside, or divided evenly on both sides.???
> Thanks regards Alan
> P.S. To European & South African psubbers. NewZealand hot favourites 
> for the world cup.




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