{"id":1905,"date":"2026-07-21T06:51:38","date_gmt":"2026-07-21T06:51:38","guid":{"rendered":"https:\/\/gearrack.top\/?p=1905"},"modified":"2026-07-21T06:51:38","modified_gmt":"2026-07-21T06:51:38","slug":"spiral-bevel-gears-for-marine-applications","status":"publish","type":"post","link":"https:\/\/gearrack.top\/fr\/spiral-bevel-gears-for-marine-applications\/","title":{"rendered":"Spiral Bevel Gears for Marine Applications"},"content":{"rendered":"
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GEAR APPLICATION GUIDE \u00b7 BEVEL GEAR \u00b7 B05<\/span><\/p>\n

Spiral Bevel Gears for Marine Applications:
\nPropulsion, Steering and Deck Machinery Gear Design<\/span><\/h1>\n

Marine bevel gears operate in the most corrosive and dynamically demanding environment of any industrial application \u2014 continuously immersed or spray-exposed to salt water, subject to hull-transmitted shock loads from wave impact, and often inaccessible for maintenance for months at a time. Spiral bevel gears are specified for marine propulsion shaft angle drives, steering gear right-angle drives, deck winch gearboxes, anchor windlass drives, and bow thruster right-angle gearboxes \u2014 all requiring material selection for marine corrosion resistance alongside the mechanical load rating calculation.<\/p>\n

17-4 PH \u00b7 Nitronic 50 \u00b7 316L \u00b7 18CrNiMo7-6<\/span>
\nDNV GL \u00b7 BV \u00b7 Lloyd’s \u00b7 M8\u2013M20<\/span>
\nPropulsion \u00b7 Steering \u00b7 Thruster \u00b7 Winch<\/span><\/div>\n<\/div>\n<\/div>\n
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CLASS APPROVAL<\/p>\n

DNV \/ BV \/ LR<\/p>\n

Marine classification society approval required for propulsion and steering gear bevel gears. DNV GL (Det Norske Veritas), Bureau Veritas (BV), and Lloyd\u2019s Register (LR) are the primary class societies. Korea Ever-Power supplies bevel gears with class society material and process certification on request<\/p>\n<\/div>\n

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MODULE RANGE<\/p>\n

M8 \u2013 M20<\/p>\n

Marine bevel gear module range. Deck winch and anchor windlass: M8\u2013M12. Steering gear ram drive: M10\u2013M16. Bow thruster right-angle: M10\u2013M18. Propulsion shaft angle drive on larger vessels: M14\u2013M20<\/p>\n<\/div>\n

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STAINLESS MATERIAL<\/p>\n

17-4 PH \/ 316L<\/p>\n

Marine-grade stainless bevel gear materials. 17-4 PH (precipitation hardened stainless): H900 condition HRC 38\u201343, excellent corrosion resistance, good strength. 316L: lower strength, used for small bevel gears in highly corrosive bilge and ballast applications<\/p>\n<\/div>\n

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SERVICE FACTOR<\/p>\n

1.5 \u2013 2.5<\/p>\n

Marine bevel gear service factors. Deck winch and anchor windlass (shock loads from wave action on cable): SF 2.0\u20132.5. Steering gear (smooth hydraulic actuation): SF 1.5. Propulsion shaft angle drive (moderate shock from propeller cavitation): SF 1.5\u20132.0<\/p>\n<\/div>\n<\/div>\n

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Marine Bevel Gear Material Selection \u2014 The Corrosion Imperative<\/h2>\n

The defining design challenge for marine spiral bevel gears \u2014 distinguishing them from all land-based bevel gear applications \u2014 is the need to combine adequate mechanical load capacity with corrosion resistance to salt water, salt spray, and the humid salt-air atmosphere found below decks on all vessels. Standard alloy steel bevel gears (20CrMnTi, 18CrNiMo7-6) provide excellent mechanical properties but will rust rapidly in the marine environment, beginning with surface pitting within weeks in a salt-spray atmosphere and progressing to tooth profile loss within months if left unprotected. The consequence of corrosion-accelerated tooth wear in a marine steering gear or anchor windlass is a loss of vessel manoeuvrability or loss of anchor control \u2014 both safety-critical failures.<\/p>\n

\"Spiral<\/p>\n

Korea Ever-Power’s spiral bevel gears for marine applications<\/a> are manufactured in three material systems matched to the load level and corrosion exposure: 17-4 PH precipitation-hardened stainless steel (H900 condition, HRC 38\u201343) for medium-to-heavy-duty marine bevel gears requiring both load capacity and salt water corrosion resistance; Nitronic 50 (XM-19) austenitic stainless (yield strength 520 MPa, excellent seawater corrosion resistance) for deck and bilge bevel gears below 50 kW where load capacity is secondary to corrosion protection; and 18CrNiMo7-6 case carburized with electroless nickel plating for high-power propulsion bevel gears where 17-4 PH’s strength is insufficient but corrosion protection can be provided by the plating and enclosed housing. All marine bevel gears from Korea Ever-Power are available with DNV GL, Bureau Veritas, or Lloyd\u2019s Register material certification.<\/p>\n

Marine classification societies (DNV GL, BV, Lloyd\u2019s Register, ClassNK, RINA) require that propulsion and steering gear components \u2014 including bevel gears in the steering transmission \u2014 are manufactured from approved materials under an approved quality management system, with inspection and documentation by a class society surveyor or to class-approved internal quality procedures. Korea Ever-Power holds ISO 9001:2015 certification and can provide marine bevel gear manufacture under class society survey for DNV GL and Bureau Veritas \u2014 the certification documentation is submitted directly to the shipyard\u2019s classification society dossier for vessel approval.<\/p>\n

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APP 01<\/p>\n

BOW THRUSTER
\nRIGHT-ANGLE DRIVE<\/p>\n<\/div>\n

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Bevel gear specification:<\/strong> M10\u2013M18, 17-4 PH H900 or 18CrNiMo7-6 with electroless nickel, spiral bevel, ratio 1:1 to 2:1, DNV GL or BV class approval, sealed housing IP67. The bow thruster right-angle bevel gearbox converts the horizontal motor shaft (mounted in the vessel\u2019s bow void) to the vertical propeller shaft of the tunnel thruster. Motor power is 100\u20133,000 kW on commercial vessels; the bevel gear operates continuously during port manoeuvring at full rated power. The gearbox housing is mounted in the thruster tunnel \u2014 a permanently wet environment exposed to sea water when the vessel is underway. 17-4 PH H900 spiral bevel gears in a 316L stainless housing with double lip seals and sacrificial zinc anodes on the housing are the standard specification for bow thruster bevel gearboxes on commercial vessels. Korea Ever-Power supplies bow thruster bevel gear replacement sets for W\u00e4rtsil\u00e4, Rolls-Royce (Kamewa), Brunvoll, and Thrustmaster thruster models.<\/p>\n<\/div>\n<\/div>\n

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APP 02<\/p>\n

STEERING GEAR
\nRAM DRIVE<\/p>\n<\/div>\n

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Bevel gear specification:<\/strong> M10\u2013M16, 17-4 PH H900 or 18CrNiMo7-6 nickel-plated, spiral bevel, ratio 1:1 to 3:1, class approved, SOLAS (Safety of Life at Sea) redundancy requirements. The vessel steering gear uses a bevel gear right-angle drive to transfer the hydraulic pump motor shaft rotation to the rudder stock. SOLAS Chapter II-1 Regulation 29 requires that all vessels above 150 GT carry steering gear capable of moving the rudder from 35\u00b0 to 35\u00b0 port-to-starboard in 28 seconds at maximum service speed, with a redundant power unit. The bevel gears in the steering gear must be designed to this emergency manoeuvring load, not just the normal steady-speed load. Korea Ever-Power\u2019s marine steering gear bevel gears are designed to SOLAS emergency steering load with a safety factor of 1.5 applied to the emergency torque, and supplied with class certification for incorporation into the steering gear classification documentation.<\/p>\n<\/div>\n<\/div>\n

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APP 03<\/p>\n

ANCHOR WINDLASS
\n& DECK WINCH<\/p>\n<\/div>\n

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Bevel gear specification:<\/strong> M8\u2013M14, 17-4 PH H900 or 316L stainless, straight or spiral bevel, ratio 1:1 to 3:1, shock service factor 2.0\u20132.5. Anchor windlass and deck mooring winch bevel gearboxes are subject to severe shock loads when the anchor cable suddenly takes up slack during vessel ranging in a seaway or when a mooring line snaps under tension. The bevel gear must absorb these shock loads without tooth fracture. Open or semi-open deck environments require maximum corrosion protection \u2014 17-4 PH H900 stainless bevel gears in stainless housings with pressurised oil lubrication and positive shaft sealing are specified for windlass gearboxes on vessels operating in Arctic and tropical marine environments. Deck equipment bevel gears also experience temperature extremes \u2014 from -40\u00b0C in Arctic service to +50\u00b0C in tropical port operation \u2014 requiring the gear lubricant viscosity selection to account for both extremes in a single oil fill.<\/p>\n<\/div>\n<\/div>\n

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APP 04<\/p>\n

NAVAL & PATROL
\nVESSEL DRIVES<\/p>\n<\/div>\n

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Bevel gear specification:<\/strong> M12\u2013M20, Nitronic 50 XM-19 or 17-4 PH H900, spiral bevel, MIL-G-17859 or DEF STAN 02-302 (Royal Navy) material certification, high shock service factor 2.5\u20133.5. Naval patrol vessels and offshore patrol vessels (OPVs) require bevel gears certified to military specifications for shock resistance \u2014 naval vessels must maintain propulsion after underwater explosion (UNDEx) events that impose severe multi-axis shock loads on the gearbox. Nitronic 50 (a nitrogen-strengthened austenitic stainless steel, yield strength 520 MPa, superior to 316L) is specified by several navies for deck equipment bevel gears because it combines high strength with the salt water corrosion resistance required for indefinite service without corrosion protection maintenance. Korea Ever-Power supplies naval specification bevel gears with MIL material certification and traceable heat treatment records on request.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

\"types<\/p>\n

Frequently Asked Questions<\/h2>\n
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Q 01<\/span><\/p>\n

What lubricant is correct for a marine bow thruster bevel gearbox, and how is the oil change managed when the thruster is mounted in a permanently wet tunnel?<\/p>\n<\/div>\n

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Marine bow thruster bevel gearboxes use ISO VG 220 or VG 320 gear oil with rust inhibitor and anti-emulsification additive packages (critical for any marine gearbox oil). Synthetic PAO-based gear oil (Kl\u00fcber Kl\u00fcbersynth GH 6-220 or equivalent) is preferred for sealed-for-long-interval service because PAO does not oxidise as rapidly as mineral oil at elevated operating temperatures, extending the service interval to 4,000\u20138,000 hours. Oil change in a thruster tunnel gearbox: most commercial thruster gearboxes are equipped with a dedicated oil drain pipe and fill connection routed to an accessible location in the bow void \u2014 oil change does not require drydocking or tunnel access when this system is correctly installed. If the vessel does not have these connections, oil change must be performed at drydocking with the tunnel dewatered. Korea Ever-Power recommends quarterly oil sampling and analysis for bow thruster gearboxes on vessels operating in warm tropical waters above 30\u00b0C \u2014 the elevated oil temperature significantly accelerates oxidation and increases water contamination risk from seal degradation. Discard and replace oil immediately if water content exceeds 0.5% by volume (Karl Fischer titration on oil sample).<\/p>\n<\/div>\n<\/div>\n

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Q 02<\/span><\/p>\n

Why is 17-4 PH preferred over 316L stainless steel for heavy-duty marine bevel gears?<\/p>\n<\/div>\n

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17-4 PH (AISI 630, UNS S17400) and 316L (UNS S31603) are both stainless steels with good marine corrosion resistance, but they differ fundamentally in strength and hardenability: 316L in the annealed condition has yield strength of 170\u2013210 MPa and cannot be hardened beyond approximately HB 200 \u2014 providing very limited bending fatigue strength for gear tooth roots. 17-4 PH in the H900 precipitation-hardened condition achieves yield strength of 1,170 MPa and HRC 38\u201343 \u2014 approximately four times the strength of annealed 316L, with bending fatigue strength sufficient for medium-to-heavy marine bevel gear applications. The trade-off: 17-4 PH has slightly lower crevice corrosion resistance than 316L in stagnant seawater (because it is a martensitic-type PH stainless rather than austenitic), but in a properly lubricated enclosed gear housing with no stagnant water contact this is not a relevant distinction. For marine bevel gears above 5 kW transmitted power: 17-4 PH H900 is the correct choice. For small marine bevel gears below 5 kW in permanently wet or bilge environments where load capacity is not the constraint: 316L annealed is acceptable and lower in cost.<\/p>\n<\/div>\n<\/div>\n

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Q 03<\/span><\/p>\n

What is the lead time for replacement spiral bevel gears for a bow thruster or steering gear at drydock?<\/p>\n<\/div>\n

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Lead time for marine spiral bevel gear replacement sets from Korea Ever-Power depends on the gear size and certification requirement: (1) Standard marine bevel gears M8\u2013M12, 17-4 PH, no class certification:<\/strong> 20\u201330 days from drawing confirmation. (2) Marine bevel gears M12\u2013M18, 17-4 PH or 18CrNiMo7-6, with DNV GL or BV material certification:<\/strong> 35\u201350 days \u2014 the additional lead time allows for class surveyor review of the material mill certificate and heat treatment records before shipment. (3) Naval specification bevel gears with MIL material certification:<\/strong> 45\u201365 days from drawing and specification confirmation. For drydocking projects with a fixed vessel arrival date at the repair yard, Korea Ever-Power recommends ordering replacement marine bevel gears at least 60\u201370 days before the planned drydock date to ensure gear availability before the vessel arrives. Emergency orders for critical propulsion or steering gear bevel gear failures at sea can be expedited \u2014 contact Korea Ever-Power\u2019s emergency response team with the vessel name, IMO number, gear geometry, and the port of repair for the fastest available supply route including air freight to the repair port.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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Explore Korea Ever-Power Gear Categories<\/h2>\n

Seven precision gear product lines for marine, industrial, energy and specialist applications worldwide.<\/p>\n<\/div>\n

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\"spur<\/p>\n
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Spur Gears<\/a><\/p>\n

M1\u2013M20 \u00b7 17-4 PH \u00b7 316L marine<\/p>\n<\/div>\n<\/div>\n

\"helical<\/p>\n
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Helical Gears<\/a><\/p>\n

Marine gearbox \u00b7 propulsion \u00b7 18CrNiMo7-6<\/p>\n<\/div>\n<\/div>\n

\"spiral<\/p>\n
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Engrenages coniques<\/a><\/p>\n

17-4 PH \u00b7 marine \u00b7 thruster \u00b7 steering<\/p>\n<\/div>\n<\/div>\n

\"worm<\/p>\n
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Worm Gears<\/a><\/p>\n

Self-locking \u00b7 winch brake \u00b7 valve drive<\/p>\n<\/div>\n<\/div>\n

\"ring<\/p>\n
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Ring Gears<\/a><\/p>\n

Stainless \u00b7 slewing \u00b7 marine planetary<\/p>\n<\/div>\n<\/div>\n

\"planetary<\/p>\n
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Planetary Gears<\/a><\/p>\n

Compact \u00b7 thruster hub \u00b7 winch drive<\/p>\n<\/div>\n<\/div>\n

\"plastic<\/p>\n
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Plastic Gears<\/a><\/p>\n

UHMWPE \u00b7 PEEK \u00b7 bilge \u00b7 instrument<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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GET A QUOTATION \u00b7 KOREA EVER-POWER<\/p>\n

Need Spiral Bevel Gears for Marine Applications?<\/h2>\n

Korea Ever-Power manufactures 17-4 PH, Nitronic 50, and 18CrNiMo7-6 spiral bevel gears for all marine applications \u2014 bow thrusters, steering gear, anchor windlass, deck winches, and naval vessel drives. DNV GL, Bureau Veritas, and Lloyd\u2019s Register material certification available. Replacement supply for W\u00e4rtsil\u00e4, Rolls-Royce, Brunvoll thruster models. Drydock emergency supply worldwide. ISO 9001:2015 certified.<\/p>\n

Request a Quotation \u2192<\/a><\/p>\n<\/div>\n

\u00c9diteur : Cxm<\/em><\/p>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

GEAR APPLICATION GUIDE \u00b7 BEVEL GEAR \u00b7 B05 Spiral Bevel Gears for Marine Applications: Propulsion, Steering and Deck Machinery Gear Design Marine bevel gears operate in the most corrosive and dynamically demanding environment of any industrial application \u2014 continuously immersed or spray-exposed to salt water, subject to hull-transmitted shock loads from wave impact, and often […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[4566],"tags":[],"class_list":["post-1905","post","type-post","status-publish","format-standard","hentry","category-application-of-gears"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1905","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/comments?post=1905"}],"version-history":[{"count":2,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1905\/revisions"}],"predecessor-version":[{"id":1910,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1905\/revisions\/1910"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/media?parent=1905"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/categories?post=1905"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/tags?post=1905"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}