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HomeMagazineInside SOTW Mag: The Art And Science Of Propping Multi-Outboard Boats

Inside SOTW Mag: The Art And Science Of Propping Multi-Outboard Boats

Marine Technology Inc., in Wentzville, Mo., has been building high-performance center console boats since introducing its MTI-V 42 powered by quad outboard engines in 2012. The 42-footer was followed by the MTI-V 57 in 2016 and since then the company has delivered several 57-footers featuring either four or five outboard engines. And in early 2021, the builder introduced the MTI-V 50 to fit between the two models.

Five outboard engines, 25 propeller blades, three shaft lengths. Multi-engine center consoles look impressive and there’s more to getting their setup right than meets the eye. Photo from the 2022 Florida Powerboat Club Miami Boat Show Poker Run by Pete Boden copyright Shoot 2 Thrill Pix.

It would be easy to assume that once the company figured out the setup with the 42-footer, the 57-foot model and its 50-foot sibling would simply be a matter of scale, but that’s why that old saying about the word “assume” remains accurate.

“Our 42 is a completely different animal than our 50 is,” said MTI founder and owner Randy Scism. “You have to test each boat. Some of the problem is the V-bottom in general. You have quite a difference in transom height as you move across. You need to worry about how high the outer-most motors are, but they can’t be too high because they’ll bark all the time.”

In performance boat parlance, “barking” means the propeller is breaking free of the water, causing the rpm to suddenly surge and the engine hits the rev limiter. It’s similar to what teams and crew chiefs experienced with the center engine on triple-outboard cats that competed in the Pro-Stock class in the 1990s.

Even though the engines are in the opposite locations on the given boats, they are the least protected in their given applications. On the triple-engine raceboats, there was no hull in front of the engine so the midsection and the lower unit took all the abuse. On center consoles, the amount of boat in front of the outboards is the least at the outer edge where the bottom meets the chine.

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