{"title":"Selden Hydraulic Systems 1, Practical Guide — Owner's Manual","description":"\u003clink rel=\"stylesheet\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0879\/4908\/2930\/files\/om-manual-v2.css\"\u003e\u003cstyle\u003e.mpom .om-tbl.nw td+td{white-space:nowrap}.mpom details.om-dd{position:relative;margin:0}.mpom details.om-dd\u003esummary{list-style:none;cursor:pointer}.mpom details.om-dd\u003esummary::-webkit-details-marker{display:none}.mpom .om-dd-menu{position:absolute;left:0;top:calc(100% + 6px);min-width:100%;width:max-content;max-width:360px;background:#fff;border:1px solid #e3e5e8;border-radius:6px;box-shadow:0 8px 24px rgba(0,0,0,.14);z-index:30;padding:6px}.mpom .om-dd-menu a{display:flex;justify-content:space-between;align-items:center;gap:14px;padding:10px 12px;border-radius:4px;font-size:14px;font-weight:600;color:#2a2b2a!important;text-decoration:none!important}.mpom .om-dd-menu a:hover{background:#f5f6f8}.mpom .om-dd-menu small{font-weight:400;color:#5f6368;white-space:nowrap}\u003c\/style\u003e\u003cdiv class=\"mpom\"\u003e\n\u003cdiv class=\"om-head\"\u003e\n\u003cdiv\u003e\n\u003cspan class=\"om-tag\"\u003eOWNER'S MANUAL\u003c\/span\u003e\u003cp class=\"om-lead\"\u003eSelden's practical guide to its earlier hydraulic sail-handling systems: basic hydraulic theory, motor sizes and speeds for hydraulic Furlex and in-mast furling, thread standards and JIC adapters, and how the boom outhaul valves behave – useful for troubleshooting.\u003c\/p\u003e\n\u003cdiv class=\"om-box\"\u003e\n\u003cdiv class=\"om-row\"\u003e\n\u003cspan\u003eDocument\u003c\/span\u003e\u003cb\u003eSelden Hydraulic Systems 1, Practical Guide Owner's Manual\u003c\/b\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-row\"\u003e\n\u003cspan\u003eFormat\u003c\/span\u003e\u003cb\u003ePDF · 33 pages · 2.1 MB\u003c\/b\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-row\" style=\"border-bottom:0\"\u003e\n\u003cspan\u003eLanguage\u003c\/span\u003e\u003cb\u003eEnglish\u003c\/b\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-acts\"\u003e\u003ca class=\"om-btn dl\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0879\/4908\/2930\/files\/Selden-Hydraulic-Systems-Practical-Guide.pdf\" target=\"_blank\" rel=\"noopener\"\u003e\u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2.4\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\u003e\u003cpath d=\"M12 4v11\"\u003e\u003c\/path\u003e\u003cpath d=\"m7 10 5 5 5-5\"\u003e\u003c\/path\u003e\u003cpath d=\"M5 20h14\"\u003e\u003c\/path\u003e\u003c\/svg\u003e Download PDF\u003c\/a\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-toc\"\u003e\n\u003ca href=\"#om-theory\"\u003eHydraulic Basics\u003c\/a\u003e\u003ca href=\"#om-motors\"\u003eMotors\u003c\/a\u003e\u003ca href=\"#om-fittings\"\u003eThreads \u0026amp; Adapters\u003c\/a\u003e\u003ca href=\"#om-furling\"\u003eFurlex \u0026amp; In-Mast\u003c\/a\u003e\u003ca href=\"#om-outhaul\"\u003eBoom Outhaul Logic\u003c\/a\u003e\u003ca href=\"#om-products\"\u003eProducts\u003c\/a\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-img\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0879\/4908\/2930\/files\/Selden-Hydraulic-Systems-Practical-Guide-Cover.png\" alt=\"Selden Hydraulic Systems 1, Practical Guide — Owner's Manual\" loading=\"lazy\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-block\" id=\"om-theory\"\u003e\n\u003ch2 class=\"om-h\"\u003eBasic Hydraulic Theory\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eHydraulic power is pressure × flow. P = F \/ A; Q = V \/ t = A × S \/ t; for a rotating pump or motor Q = D × n and torque M = ΔP × D \/ 2π.\u003c\/li\u003e\n\u003cli\u003eUnits: 10N\/cm2 = 100.000Pa = 0.1 MPa = 1 bar ~1kg\/cm2; 1l = 1000cm3; flow in l\/min; displacement D in cm3; torque in Nm.\u003c\/li\u003e\n\u003cli\u003eWhen the load on a cylinder or motor rises, system pressure and pump-motor current rise automatically and flow drops – the pump curve.\u003c\/li\u003e\n\u003cli\u003ePressure loss (\"friction\") depends on hose diameter and length, bend radii and geometry, and rises with flow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eWorked example (piston pump – cylinder):\u003c\/b\u003e pump piston A1 = 10cm2, cylinder piston A2 = 100cm2. 100N on the pump piston over 100cm in 1 min gives P = 10 N\/cm2 (1 bar), Q = 1000cm3\/min (1 l\/min), so the cylinder delivers F2 = 1000N = 1kN over S2 = 10cm. This is the principle of a hand-pumped backstay adjuster: the bigger the area ratio, the bigger the load.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-block\" id=\"om-motors\"\u003e\n\u003ch2 class=\"om-h\"\u003eSelden Hydraulic Motors\u003c\/h2\u003e\n\u003cdiv class=\"om-tbl nw\"\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eMotor\u003c\/th\u003e\n\u003cth\u003eDisplacement\u003c\/th\u003e\n\u003cth\u003eRecommended flow\u003c\/th\u003e\n\u003cth\u003eSpeed\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFurlex 300H, 400H and in-mast furling\u003c\/td\u003e\n\u003ctd\u003eOML12.5\u003c\/td\u003e\n\u003ctd\u003e12.5 cm3\u003c\/td\u003e\n\u003ctd\u003e10 l\/min at 40 bar\u003c\/td\u003e\n\u003ctd\u003e10000\/12.5 = 800 n\/min\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFurlex 500\u003c\/td\u003e\n\u003ctd\u003eOMM20\u003c\/td\u003e\n\u003ctd\u003e20 cm3\u003c\/td\u003e\n\u003ctd\u003e20 l\/min at 40 bar\u003c\/td\u003e\n\u003ctd\u003e20000\/20 = 1000 n\/min\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCutter Furlex (400H) and in-mast furling on the 20 l\/min powerpac\u003c\/td\u003e\n\u003ctd\u003eOML20 (instead of OML12.5)\u003c\/td\u003e\n\u003ctd\u003e20 cm3\u003c\/td\u003e\n\u003ctd\u003e20 l\/min\u003c\/td\u003e\n\u003ctd\u003e1000 n\/min\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003cp class=\"om-note\"\u003eOn a 20 l\/min powerpac an OML12.5 would turn 20000\/12.5 = 1600 n\/min – too fast – so it is changed for an OML20. An OMM20 has different dimensions and would not fit.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-block\" id=\"om-fittings\"\u003e\n\u003ch2 class=\"om-h\"\u003eThreads \u0026amp; JIC Adapters\u003c\/h2\u003e\n\u003cp\u003eSelden hydraulic fittings are BSPP with 60° cone, British Standard BS 5200 \"K4\" (also written G1\/4\", G3\/8\", G1\/2\"). Where a system uses JIC fittings, hoses with JIC 37° female ends can be fitted with an adapter in place of the original male BSPP coupling:\u003c\/p\u003e\n\u003cdiv class=\"om-tbl nw\"\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eBSPP\u003c\/th\u003e\n\u003cth\u003eTo JIC 37° male\u003c\/th\u003e\n\u003cth\u003eParker Triple-Lok SS adapter\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1\/4 BSPP\u003c\/td\u003e\n\u003ctd\u003eJIC 7\/16-20\u003c\/td\u003e\n\u003ctd\u003e4-4F4OMXSS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e3\/8 BSPP\u003c\/td\u003e\n\u003ctd\u003eJIC 9\/16-18\u003c\/td\u003e\n\u003ctd\u003e6-6F4OMXSS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1 \/2 BSPP\u003c\/td\u003e\n\u003ctd\u003eJIC 3\/4-16\u003c\/td\u003e\n\u003ctd\u003e8-8F4OMXSS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003cp\u003eThe adapters include a plastic sealing washer on the BSPP side.\u003c\/p\u003e\n\u003cdiv class=\"om-tbl nw\"\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eG BSPP\u003c\/th\u003e\n\u003cth\u003eThread\u003c\/th\u003e\n\u003cth\u003eDash size\u003c\/th\u003e\n\u003cth\u003eØM (in)\u003c\/th\u003e\n\u003cth\u003eØM (mm)\u003c\/th\u003e\n\u003cth\u003eA (mm)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1\/4\"\u003c\/td\u003e\n\u003ctd\u003e1\/4-19\u003c\/td\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003ctd\u003e0.51\u003c\/td\u003e\n\u003ctd\u003e13\u003c\/td\u003e\n\u003ctd\u003e~11\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e3\/8\"\u003c\/td\u003e\n\u003ctd\u003e3\/8-19\u003c\/td\u003e\n\u003ctd\u003e6\u003c\/td\u003e\n\u003ctd\u003e0.65\u003c\/td\u003e\n\u003ctd\u003e16.5\u003c\/td\u003e\n\u003ctd\u003e~12\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1\/2\"\u003c\/td\u003e\n\u003ctd\u003e1\/2-14\u003c\/td\u003e\n\u003ctd\u003e8\u003c\/td\u003e\n\u003ctd\u003e0.82\u003c\/td\u003e\n\u003ctd\u003e20.83\u003c\/td\u003e\n\u003ctd\u003e~14\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003cp\u003eThe guide also has approximately 1:1 sketches of the 1\/4\" and 3\/8\" couplings for identification, and hose \/ coupling layouts for Furlex 300, 400 and 500 (glands 540-895 and 540-889), mast motors OML12,5 and OML20, and booms 200, 250 and 300 – see the PDF.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-block\" id=\"om-furling\"\u003e\n\u003ch2 class=\"om-h\"\u003eHydraulic Furlex \u0026amp; In-Mast Furling Circuits\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSelden does not supply the powerpacs and valve blocks for hydraulic Furlex and in-mast furling; the guide shows a common solution.\u003c\/li\u003e\n\u003cli\u003eIf one powerpac also drives winches and two functions run at once, oil takes the path of least resistance – the lightly loaded motor runs faster.\u003c\/li\u003e\n\u003cli\u003eFit a pressure-reducing valve in the in-mast furling circuit: working pressure is generally 140 bar and must be reduced, at least for RB systems (120 bar). It acts only in the MAIN IN direction, bypassing oil at the set pressure to limit torque on the tack assembly and profile if the sail or outhaul line jams while furling.\u003c\/li\u003e\n\u003cli\u003eIn each direction the flow-control valve acting is the one on the return from the motor.\u003c\/li\u003e\n\u003cli\u003eControl box 532-426 is the same for 12 and 24 V; only the relays K1-K8 differ.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"om-block\" id=\"om-outhaul\"\u003e\n\u003ch2 class=\"om-h\"\u003eHow the Boom Outhaul Valves Behave\u003c\/h2\u003e\n\u003cdiv class=\"om-tbl nw\"\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eSituation\u003c\/th\u003e\n\u003cth\u003eWhat happens\u003c\/th\u003e\n\u003cth\u003eManometer 3 \/ 38\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBOOM OUT pressed\u003c\/td\u003e\n\u003ctd\u003eOvercentre valve 33.2 closed, oil passes its non-return valve; 33.1 opened by servo.\u003c\/td\u003e\n\u003ctd\u003e3 = working pressure; 38 slightly less\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBOOM OUT, line jammed or too much sail \/ wind load\u003c\/td\u003e\n\u003ctd\u003eRelief valve 2.4 opens; no flow except through 2.4.\u003c\/td\u003e\n\u003ctd\u003eBoth show the max working pressure set on 2.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSailing, normal wind\u003c\/td\u003e\n\u003ctd\u003eWind load pressurizes the cylinder B-chamber; 33.2 stays closed below its setting.\u003c\/td\u003e\n\u003ctd\u003e3 = zero; 38 = pressure from wind\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWind load exceeds the 33.2 setting\u003c\/td\u003e\n\u003ctd\u003e33.2 opens and the piston moves; rod-volume difference is made up from the reservoir.\u003c\/td\u003e\n\u003ctd\u003e3 = zero; 38 = 33.2 setting\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBOOM IN pressed\u003c\/td\u003e\n\u003ctd\u003e33.1 closed, oil passes its non-return valve; 33.2 opened by servo.\u003c\/td\u003e\n\u003ctd\u003e3 = working pressure; 38 lower\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuthaul gives way in moderate wind\u003c\/td\u003e\n\u003ctd\u003eA and B hoses mixed up between valve block and cylinder: 33.1 (much lower setting) takes the load. Refit the hoses correctly; temporarily swap A and B at the quick couplings.\u003c\/td\u003e\n\u003ctd\u003eBoth zero\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003cp class=\"om-note\"\u003eHose B is on the starboard side. Pos 35 is the emergency valve.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cp class=\"om-note\"\u003eNeed a part that isn't listed? \u003ca href=\"\/pages\/contact\"\u003eAsk us to source it\u003c\/a\u003e and quote the part number from the PDF.\u003c\/p\u003e\n\u003ch2 class=\"om-h\" id=\"om-products\"\u003eProducts in this Manual\u003c\/h2\u003e\n\u003c\/div\u003e","products":[],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0879\/4908\/2930\/collections\/Selden-Hydraulic-Systems-Practical-Guide-Cover.png?v=1792517332","url":"https:\/\/www.mauripro.com\/collections\/owners-manuals-selden-hydraulic-systems-practical-guide.oembed","provider":"MAURIPRO Sailing","version":"1.0","type":"link"}