From personal_submersibles at psubs.org Fri Sep 1 13:44:13 2023 From: personal_submersibles at psubs.org (Raphael SOULIAC via Personal_Submersibles) Date: Fri, 1 Sep 2023 19:44:13 +0200 Subject: [PSUBS-MAILIST] Ribs outside hull Message-ID: Hey guys, i've got a quick question. The design i'm working on has a very narrow hull (?ID 650mm) so i wanted to put the renforcing ribs on the outside of the hull. The ABS spreasheet give me 1113ft of max depth but it's for the ribs on the inside. What would be the difference between this and the real max depth ? Raphael -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Ext_ribs_idea.pdf Type: application/pdf Size: 95059 bytes Desc: not available URL: From personal_submersibles at psubs.org Fri Sep 1 14:20:26 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Fri, 01 Sep 2023 18:20:26 +0000 Subject: [PSUBS-MAILIST] Ribs outside hull In-Reply-To: References: Message-ID: The ABS Rules provide a separate set of equations to use for determining all of your critical pressures when using external framing. You need to calculate accordingly. In general, external framing provides more stiffness than internal for the same amount of material, but there are drawbacks. Welds between your hull shell and any external stiffeners must be CJP, as opposed to simply continuous. Also, be aware that free filling spaces between the pressure hull and any external hydrodynamic fairings represent a large volume of water which must be moved along with the hull, and that inertia will consume a substantial fraction of propulsion power. If you have no fairings, you will still be moving a boundary layer defined by the drag of the exposed stiffeners, so you must plan your power budget accordingly. You also need to figure out how to mount all of your internal equipment, since external framing implies the loss of what would otherwise be a bunch of convenient structure for clamping to. Sean -------- Original Message -------- On Sep. 1, 2023, 11:44, Raphael SOULIAC via Personal_Submersibles wrote: > Hey guys, i've got a quick question. The design i'm working on has a very narrow hull (?ID 650mm) so i wanted to put the renforcing ribs on the outside of the hull. > > The ABS spreasheet give me 1113ft of max depth but it's for the ribs on the inside. > > What would be the difference between this and the real max depth ? > > Raphael -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Sep 1 14:34:16 2023 From: personal_submersibles at psubs.org (Raphael SOULIAC via Personal_Submersibles) Date: Fri, 1 Sep 2023 20:34:16 +0200 Subject: [PSUBS-MAILIST] Ribs outside hull In-Reply-To: References: Message-ID: I see, the easiest solution is the good old internal ribs. Thanks. Raphael Le ven. 1 sept. 2023 ? 20:21, Sean T. Stevenson via Personal_Submersibles < personal_submersibles at psubs.org> a ?crit : > The ABS Rules provide a separate set of equations to use for determining > all of your critical pressures when using external framing. You need to > calculate accordingly. In general, external framing provides more stiffness > than internal for the same amount of material, but there are drawbacks. > > Welds between your hull shell and any external stiffeners must be CJP, as > opposed to simply continuous. > > Also, be aware that free filling spaces between the pressure hull and any > external hydrodynamic fairings represent a large volume of water which must > be moved along with the hull, and that inertia will consume a substantial > fraction of propulsion power. If you have no fairings, you will still be > moving a boundary layer defined by the drag of the exposed stiffeners, so > you must plan your power budget accordingly. > > You also need to figure out how to mount all of your internal equipment, > since external framing implies the loss of what would otherwise be a bunch > of convenient structure for clamping to. > > Sean > > -------- Original Message -------- > On Sep. 1, 2023, 11:44, Raphael SOULIAC via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > Hey guys, i've got a quick question. The design i'm working on has a very > narrow hull (?ID 650mm) so i wanted to put the renforcing ribs on the > outside of the hull. > > The ABS spreasheet give me 1113ft of max depth but it's for the ribs on > the inside. > > What would be the difference between this and the real max depth ? > > Raphael > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sun Sep 3 00:51:40 2023 From: personal_submersibles at psubs.org (irox via Personal_Submersibles) Date: Sun, 03 Sep 2023 04:51:40 +0000 Subject: [PSUBS-MAILIST] Ribs outside hull Message-ID: <4767332f-5e7c-89f8-1e12-62d4d0544a37@ix.netcom.com> For those interested the stiffener strength calculations can be found on page 52 of the Rules for Building and Classing Underwater Vehicles and Hyperbaric Facilities, which can be found here: https://ww2.eagle.org/content/dam/eagle/rules-and-guides/current/special_service/7_rulesforbuildingandclassingunderwatervehiclessystemsandhyperbaricfacilities_2021/uwvs-rules-jan21.pdf -----Original Message----- From: Personal Submersibles General Discussion Sent: Sep 1, 2023 11:35 AM To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] Ribs outside hull I see, the easiest solution is the good old internal ribs. Thanks. Raphael Le ven. 1 sept. 2023 à 20:21, Sean T. Stevenson via Personal_Submersibles a écrit : The ABS Rules provide a separate set of equations to use for determining all of your critical pressures when using external framing. You need to calculate accordingly. In general, external framing provides more stiffness than internal for the same amount of material, but there are drawbacks. Welds between your hull shell and any external stiffeners must be CJP, as opposed to simply continuous. Also, be aware that free filling spaces between the pressure hull and any external hydrodynamic fairings represent a large volume of water which must be moved along with the hull, and that inertia will consume a substantial fraction of propulsion power. If you have no fairings, you will still be moving a boundary layer defined by the drag of the exposed stiffeners, so you must plan your power budget accordingly. You also need to figure out how to mount all of your internal equipment, since external framing implies the loss of what would otherwise be a bunch of convenient structure for clamping to. Sean -------- Original Message -------- On Sep. 1, 2023, 11:44, Raphael SOULIAC via Personal_Submersibles < personal_submersibles at psubs.org (mailto:personal_submersibles at psubs.org)> wrote: Hey guys, i've got a quick question. The design i'm working on has a very narrow hull (ØID 650mm) so i wanted to put the renforcing ribs on the outside of the hull. The ABS spreasheet give me 1113ft of max depth but it's for the ribs on the inside. What would be the difference between this and the real max depth ? Raphael _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org (mailto:Personal_Submersibles at psubs.org) http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Sep 5 19:21:57 2023 From: personal_submersibles at psubs.org (irox via Personal_Submersibles) Date: Tue, 05 Sep 2023 23:21:57 +0000 Subject: [PSUBS-MAILIST] OCEAN 2023 conference in Biloxi MS Message-ID: I'm planning on attending this. Any psubers going to be around there? https://gulfcoast23.oceansconference.org/ Cheers, Ian.