The length and size of a barrel on a propeller is often overlooked, yet it is one of the most important features when dialing in a boat. In terms of barrel diameter, a propeller can have a solid hub with broached splines (CNC Cleaver), a medium sized barrel (Trophy Plus, Pro Max), or a full-sized barrel. Barrels also come in different lengths and some have flares.
Mercury Racing offers different barrel lengths on the Bravo I, Maximus, and MAX5 propeller families. The longer and wider the barrel, the more stern lift the propeller will generate. The same goes for having a flare on the end of barrel. A long barrel with a flare acts as a miniature trim tab, providing lift and improving hole shot.
The Lab Finished Maximus LT and ST have been a staple for fine tuning lifting characteristics among twin engine sterndrives for years:
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For many high-speed applications, having a long barrel can be a detriment, causing the boat to run too flat. The Bravo I FS, Bravo I XS, Bravo I OC, MAX5, MAX5 ST, and Maximus ST all feature shortened and tuned barrels to negate this. The Bravo I OC and MAX5 ST represent the most extreme versions of this treatment, featuring very short barrels for ultra-lightweight, high horsepower outboard applications.
If you are up to speed on our other Prop School Blogs, you will know that the barrel is not the only part of the propeller that provides lift, not by a long shot. If a propeller is generating too much lift due to diameter or blade count, the barrel is often the first part of the propeller to “hit the chopping block”.
The MAX5 ST is suitable for lightweight bass boats and catamarans featuring the 250R, 300R, and 450R outboards.
The Bravo I OC is specifically designed for twin engine two stroke powered catamarans.