{"product_id":"martyr-cmt21-zinc-teardrop-hull-anode-5x2x0-8-194-cmt21","title":"Martyr CMT21 Zinc Teardrop Hull Anode – 5\" x 2\" x 0.8\" | Bolt-On | Saltwater","description":"\u003ch2\u003eMartyr CMT21 Zinc Teardrop Hull Anode\u003c\/h2\u003e\n\u003cp\u003eA mid-size zinc teardrop hull anode designed for bolt-on installation on hulls, keels, rudders, and other underwater surfaces in saltwater. The teardrop profile delivers a low-drag, hydrodynamic shape that sheds water cleanly and minimizes resistance while providing reliable sacrificial protection against galvanic corrosion. At 5\" long, the CMT21 offers more sacrificial mass than the compact \u003ca href=\"\/products\/martyr-cmt20-zinc-teardrop-hull-anode-3-4x1-8x0-6-194-cmt20\"\u003eCMT20\u003c\/a\u003e, making it a better fit for larger vessels or longer intervals between haulouts.\u003c\/p\u003e\n\n\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSteel, aluminum, and fiberglass hulls in saltwater\u003c\/li\u003e\n\u003cli\u003eRudder faces, keel leading edges, and flat underwater surfaces\u003c\/li\u003e\n\u003cli\u003eMid-size to larger inboard and outboard vessels\u003c\/li\u003e\n\u003cli\u003eAny application requiring a mid-format teardrop bolt-on zinc anode\u003c\/li\u003e\n\u003cli\u003eUpgrade from the CMT20 when more sacrificial mass is needed\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e CMT21\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSKU:\u003c\/strong\u003e 194-CMT21\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Military-grade zinc alloy (sacrificial)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 5\"L × 2\"W × 0.8\"H (approx. 127mm × 51mm × 20mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProfile:\u003c\/strong\u003e Teardrop \/ hydrodynamic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting:\u003c\/strong\u003e Bolt-on\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBest For:\u003c\/strong\u003e Saltwater\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e ~220 g\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eAlloy Selection Guide\u003c\/h3\u003e\n\u003cp\u003eTeardrop hull anodes are available in three alloys for different water types:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eZinc\u003c\/strong\u003e – saltwater (open ocean, consistent high salinity) – \u003cstrong\u003eCMT21 (this product)\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAluminum\u003c\/strong\u003e – saltwater \u0026amp; brackish water (coastal, estuaries, mixed salinity)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnesium\u003c\/strong\u003e – freshwater only (lakes, rivers, reservoirs)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Hull Anodes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/martyr-cmt20-zinc-teardrop-hull-anode-3-4x1-8x0-6-194-cmt20\"\u003eMartyr CMT20 Zinc Teardrop Hull Anode – 3.4\" × 1.8\" (smaller)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/martyr-zinc-teardrop-hull-anode-3-1-2x1-3-4in-cmt-t20\"\u003eMartyr CMT-T20 Zinc Teardrop Hull Anode – 3-1\/2\" × 1-3\/4\"\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/martyr-zinc-teardrop-hull-anode-5-1-4x2in-cmt-t21\"\u003eMartyr CMT-T21 Zinc Teardrop Hull Anode – 5-1\/4\" × 2\"\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/11062241067044\"\u003eMartyr CMMZC406 Zinc Hull Plate Anode – 4.4\" × 9\"\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/11062238019620\"\u003eMartyr CMDIVERHZ Heavy Hull Plate Anode – Zinc 1\" × 6\" × 12\"\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/11062238216228\"\u003eMartyr CMDIVERZ Zinc Diver’s Dream Hull Anode – ½\" × 6\" × 12\"\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\n\u003cp\u003eThe CMT21 is the right teardrop anode when the smaller \u003ca href=\"\/products\/martyr-cmt20-zinc-teardrop-hull-anode-3-4x1-8x0-6-194-cmt20\"\u003eCMT20\u003c\/a\u003e isn’t providing enough mass for the vessel’s protection requirements or haulout interval. The teardrop shape is preferred over flat plate anodes in areas with water flow — it sheds water cleanly and creates less drag than a flat profile of equivalent mass, making it a good choice for rudder faces and keel leading edges where hydrodynamics matter.\u003c\/p\u003e\n\u003cp\u003eZinc is the correct alloy for full saltwater use. If your vessel operates in brackish or mixed-salinity water, an aluminum teardrop anode is the better choice — zinc can passivate in lower-salinity conditions and lose effectiveness. For freshwater, magnesium is the only alloy that provides meaningful protection.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":50999092445220,"sku":"194-CMT21","price":15.49,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/194-CMT21.jpg?v=1782799308","url":"https:\/\/marisolmarine.com\/products\/martyr-cmt21-zinc-teardrop-hull-anode-5x2x0-8-194-cmt21","provider":"Marisol Marine Company","version":"1.0","type":"link"}