Davit Design

[ella0509]

Hello.

Does anyone have any nice reference data to Davit designs?? Looking for possible calculations or standard component layouts and sizes etc....

Thanks,
Lee

 

[waskillywabbit]

PIP?

Brian

 

[arto]

for door/hatch davits, maybe try tube turns:

http://www.sypristechnologies.com/technology/content.asp?page_id=106

or maybe navy type?:

http://www.juniperindustries.com/scuttles/index.html

http://www.standardequipmentco.com/marine/63.htm

http://marine-doors-hatches.com/catalog-list.html

http://www.freemanmarine.com/ProductsHatches.htm

 

[doct9960]

Pressure Vessel Design Manual by Dennis Moss has a section about "Design of Davits".

Process Industry Practices (PIP) have standard drawings on manway davits and column davits.

 

[jnleroux]

Pressure Vessel Handbook by Eugene Megyesy has a page on horizontal and vertical opening manway davits. It does not go through calculations, but rather drawings with a table covering different cover sizes. These range from 150# to 900# and 12" to 24".

 

[ella0509]

Thanks for your reply's. I've got the Megyesy handbook, unfortuanately our vessels are slightly smaller than those listed (8" - 10" Flanges). I know a davit is not really required for the smaller flanges, but our customer has requested them.....

I'm pretty o.k. with the physical mechanical design of the davit and its workings - however I'm fairly limited with information regarding there workings to the design codes (ASME VIII Div1 and PD5500) as well as the P.E.D. - as these are coded vessels for third party inspection, I'm worried we'll get pulled up on something when its too late to put it right!!

Regards,
Lee

 

[jnleroux]

Lee,
You should be able to use the design for the 12" on the 8" & 10". The material lists 5/8" eye-bolt and plate. With this size, you will still have nearly 0.25" on both edges of the flange for a fillet weld (8" - 150#). The davit will be a little over designed, but shouldn't present a problem. I have not worked with PD5500, Specification for Unfired fusion welded pressure vessels, so I cannot be sure how it addresses structural members. Under ASME VIII, D1, you should consider the davit a nonpressure attachment. Non Mandatory Appendix G, Suggested Good Practice Regarding Pipe Reactions and Design of Supports and Attachments may be useful.

The third party inspection will typically review the construction drawings and make sure that the attachments have been built as designed. They will visually inspect the attachments welds and may PT or MT them as well. Obviously, the design materials of the attachments will need to be compatible with the vessel and the welding will need to be covered by an approved welding procedure.

Best of luck,
John