Mercury Racing has once again delivered something for the high-performance crowd, unveiling a new 15-inch Heavy-Duty Conventional Midsection (HD CMS) for its 200R, 300R, and competition-only 200 ROS and 300 ROS outboards. It is built for boats that live on the edge — the kind of catamarans and fast monohulls that hammer through chop, carve hard turns, and spend more time at full throttle than idle.
The HD CMS is designed to handle that kind of punishment. It features forged transom brackets, solid motor mounts, and a reinforced drive shaft housing — the backbone of any serious offshore setup. Mercury has also fitted a single-ram trim system, chosen for its simplicity and strength under heavy load. Together, these updates deliver a more planted ride, sharper handling, and the kind of durability demanded by racers and performance boaters alike.
By lowering the engine’s centre of gravity, the 15-inch HD CMS improves balance at speed and helps the prop stay hooked up in rough water. That means less porpoising, tighter cornering, and better control in the kind of conditions that make lesser rigs nervous. It also maintains compatibility with Digital Throttle & Shift (DTS) or traditional mechanical controls, so it slots easily into new builds or retrofit projects.
For Australasian trailerboat and powerboat owners who like to push limits — whether it’s circuit racing, bar crossings, or lake runs — this midsection represents a solid upgrade path. It’s engineered not just for straight-line performance, but for the demanding mix of speed and agility that defines real-world boating in local conditions.
Mercury Racing says the 15-inch HD CMS will be available to order in late 2025, and it’s likely to find a home beneath some of the region’s quickest hulls soon after.
Strong, simple, and purpose-built, this midsection is a reminder that while horsepower gets headlines, handling wins races — and keeps boats shiny side up.
Learn more at Mercury Marine
