{"product_id":"qbp127016","title":"Raymarine ST800 Through-Hull Speed and Temperature Transducer, Low-Profile, Retractable","description":"\u003ch6\u003eOverview\u003c\/h6\u003e\u003cp\u003eThe Raymarine ST800 is a through-hull speed and water temperature transducer for boats that need analog speed and temperature data without adding a larger sonar transducer. It uses a retractable insert in a low-profile through-hull housing, with only 5 mm or 3\/16 in extending outside the hull to help keep drag low.\u003c\/p\u003e\u003cp\u003eThis transducer is used when a vessel has an in-hull transducer setup but still needs paddlewheel speed and water temperature sent into the Raymarine system. It has a 9 m or 30 ft analog cable, works over a 2 to 45 knot speed range, and uses a 51 mm or 2 in hole size for installation.\u003c\/p\u003e\u003cp\u003eThe ST800 range is offered with plastic or bronze housing options, so the hull material and installation environment can be matched before cutting the hull. The insert is retractable, and the housing includes a water valve that helps reduce water entry into the bilge when the paddlewheel insert is removed for routine cleaning.\u003c\/p\u003e\u003ch6\u003eKey features\u003c\/h6\u003e\u003cul\u003e\n\u003cli\u003eMeasures boat speed through the water and water temperature from a single through-hull sensor.\u003c\/li\u003e\n\u003cli\u003eAnalog output for compatible Raymarine speed, temperature, and fishfinder installations.\u003c\/li\u003e\n\u003cli\u003eRetractable insert allows paddlewheel service without removing the through-hull housing.\u003c\/li\u003e\n\u003cli\u003eLow-profile housing extends only 5 mm or 3\/16 in outside the hull to help reduce drag.\u003c\/li\u003e\n\u003cli\u003eSpeed range of 2 to 45 knots supports common cruising, sailing, and fishing use.\u003c\/li\u003e\n\u003cli\u003e9 m or 30 ft analog cable gives practical routing length for many helm and electronics layouts.\u003c\/li\u003e\n\u003cli\u003e51 mm or 2 in hole size supports installation in compatible through-hull locations.\u003c\/li\u003e\n\u003cli\u003eSuitable for 0 to 8 degree deadrise angles when installed in the proper hull location.\u003c\/li\u003e\n\u003cli\u003eIncluded Y-cable is for CP300 and CP370 installations only.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch6\u003eVariants\u003c\/h6\u003e\u003cp\u003eThe Raymarine ST800 is available in two material configurations. Both versions are speed and temperature through-hull transducers with analog output, a retractable insert, a low-profile housing, and the same 9 m or 30 ft cable length.\u003c\/p\u003e\u003cp\u003eThe material choice changes the housing and the hull materials it is suited for. Plastic is listed for fiberglass and metal hulls, while bronze is listed for fiberglass and wood hulls.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eE66071: Material Plastic. This version uses the plastic P120-style housing and is listed for fiberglass or metal hulls, making it the lighter housing option in the range.\u003c\/li\u003e\n\u003cli\u003eE66072: Material Bronze. This version uses the bronze B120-style housing and is listed for fiberglass or wood hulls, making it a common fit where a bronze through-hull is preferred.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch6\u003eInstallation and setup\u003c\/h6\u003e\u003cp\u003eThe ST800 should be installed where clean water flow passes the paddlewheel while the boat is underway. On sailboats and planing hulls, placement matters because turbulence, air bubbles, or heavy aeration can affect speed readings.\u003c\/p\u003e\u003cp\u003eThe retractable insert is useful for boats that operate in weed, silt, or fouling-prone water, since the paddlewheel can be removed for cleaning while the housing remains in place. The water valve helps reduce bilge water entry during that maintenance step, but normal care is still required whenever any through-hull insert is opened.\u003c\/p\u003e\u003ch6\u003eCompatibility and fit\u003c\/h6\u003e\u003cp\u003eThis is an analog speed and temperature transducer, not an NMEA 2000 sensor by itself. It should be matched to compatible Raymarine displays, sonar modules, or instrument systems that accept this type of analog speed and temperature input.\u003c\/p\u003e\u003cp\u003eThe plastic and bronze versions have different hull-material listings, so the housing material should be checked against the boat before purchase. For cored hulls, steep deadrise, tight bilge areas, or metal hull installations, the final location and sealing method should be planned carefully before drilling.\u003c\/p\u003e\u003ch6\u003eUse cases on board\u003c\/h6\u003e\u003cp\u003eThe ST800 is a practical fit for cruising sailboats, racing sailboats, leisure boats, and fishing boats that need through-water speed rather than relying only on GPS speed over ground. Through-water speed is especially useful for sail trim, current awareness, performance comparisons, and instrument calculations that depend on water movement past the hull.\u003c\/p\u003e\u003cp\u003eIt also suits refits where an in-hull depth or sonar transducer is already in use and the boat still needs a separate source for speed and water temperature data.\u003c\/p\u003e\u003ch6\u003eMaintenance and care\u003c\/h6\u003e\u003cp\u003ePaddlewheel sensors should be kept clean so marine growth, paint buildup, or debris does not slow the wheel or stop it from turning. During haul-out or regular service, inspect the wheel, pin, and housing area, and avoid antifouling coatings that are not approved for transducer faces or moving parts.\u003c\/p\u003e","brand":"Raymarine","offers":[{"title":"Plastic","offer_id":52581985255605,"sku":"QBP127016-V1","price":274.99,"currency_code":"USD","in_stock":false},{"title":"Bronze","offer_id":52581985288373,"sku":"QBP127016-V2","price":0.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0977\/8171\/1029\/files\/1335242_qbp127016.webp?v=1780202080","url":"https:\/\/www.qualityboatparts.com\/products\/qbp127016","provider":"Quality Boat Parts","version":"1.0","type":"link"}