Bottom Line Up Front: The Mud Motor market is 10 times the size of the Tractor Racing/Pulling market and will come to drive the modification market, and Briggs OWNS this market.
Surface drives for marine propulsion have been around since the Hickman Sea Sled of 1914. http://en.wikipedia.org/wiki/Hickman_sea_sled The prop is only immersed up to it's hub; half of it is out of the water, and a special supercavitating/superventilating prop is used. Later incarnations were developed in Southeast Asia ("Longtail" Long-tail boat - Wikipedia ), and in the San Francisco Bay Area as the Arnesson Surface Drive (http://www.powerandmotoryacht.com/boats/arneson-drive#:~:text=The%20Arneson%20Surface%20Drive%20%28ASD%29%20is%20actually%20a,he%20invented%20a%20device%20that%20automatically%20cleaned%20pools) starting in the 1970s. These things have been adopted and embraced and developed by the hunting/fishing crowd in the South and Midwest to access water too shallow to drown in, but not too clogged with weed (airboats are still superior for that).
Brands include Beavertail, Mud-Skipper, Mud Walker, MudBuddy, Swamp Runner, Copperhead, Gator-Tail. mud motors - Bing And it's Briggs, Briggs, Briggs. They have embraced this market, and the top of the heap is their 993cc big block EFI engine, rated at 40 HP @ 3600 RPM, with factory authorized governed speed up to 4750 RPM, WITH a 3 year warranty. Vertical: http://www.vanguardpower.com/na/en_us/product-catalog/engines/big-block-vtwin-vertical-shaft/vanguard-400-gross-hp-efi--marine.html and Horizontal http://www.vanguardpower.com/na/en_us/product-catalog/engines/big-block-vtwin-horizontal-shaft/vanguard-400-gross-hp-efi--marine.html
I have it directly from one of the modification shops that they are concentrating their development fire on THIS engine. People run the snot out of them till the warranty runs out, then mod the hell out of them in the first rebuild. And this service is much more like aviation usage than tractor pulling, or tractor dirt track racing. Picture an aluminum jon boat with 3 guys, and a load of decoys running flat-out for 10-15 miles to THE SPOT from the nearest launch ramp. Expect big throttle bodies to use with the EFI, better rods, better valve trains, etc.
This is not to say that development on the Kohler CH750 (their mid-sized engine, they also have a Big Block, see TiPi's build thread for an overview of the various classes of engines from the major manufacturers.) is dead. It's still the favorite of the tractor pullers, and there are 2 different brand new CNC hemi heads for this engine, for example (Midwest Super Cubs and Zach Kerber Engineering).
There has been a lot of useful discussion on other recent threads under this forum heading, including on some of the deficiencies of the Kohler. I've also asked the Admins for separate discussion area for Small Industrial V-Twins. And this video by Lonestar Hovercraft compares 3 different brands of roughly 25 HP engines, with a slight win for Kohler http://www.bing.com/videos/search?q=lone+star+hovercraft+briggs+kohler+predator&&view=detail&mid=DFF894FCC0F6EF74E8D8DFF894FCC0F6EF74E8D8&&FORM=VRDGAR&ru=/videos/search?q=lone+star+hovercraft+briggs+kohler+predator&FORM=HDRSC3
Surface drives for marine propulsion have been around since the Hickman Sea Sled of 1914. http://en.wikipedia.org/wiki/Hickman_sea_sled The prop is only immersed up to it's hub; half of it is out of the water, and a special supercavitating/superventilating prop is used. Later incarnations were developed in Southeast Asia ("Longtail" Long-tail boat - Wikipedia ), and in the San Francisco Bay Area as the Arnesson Surface Drive (http://www.powerandmotoryacht.com/boats/arneson-drive#:~:text=The%20Arneson%20Surface%20Drive%20%28ASD%29%20is%20actually%20a,he%20invented%20a%20device%20that%20automatically%20cleaned%20pools) starting in the 1970s. These things have been adopted and embraced and developed by the hunting/fishing crowd in the South and Midwest to access water too shallow to drown in, but not too clogged with weed (airboats are still superior for that).
Brands include Beavertail, Mud-Skipper, Mud Walker, MudBuddy, Swamp Runner, Copperhead, Gator-Tail. mud motors - Bing And it's Briggs, Briggs, Briggs. They have embraced this market, and the top of the heap is their 993cc big block EFI engine, rated at 40 HP @ 3600 RPM, with factory authorized governed speed up to 4750 RPM, WITH a 3 year warranty. Vertical: http://www.vanguardpower.com/na/en_us/product-catalog/engines/big-block-vtwin-vertical-shaft/vanguard-400-gross-hp-efi--marine.html and Horizontal http://www.vanguardpower.com/na/en_us/product-catalog/engines/big-block-vtwin-horizontal-shaft/vanguard-400-gross-hp-efi--marine.html
I have it directly from one of the modification shops that they are concentrating their development fire on THIS engine. People run the snot out of them till the warranty runs out, then mod the hell out of them in the first rebuild. And this service is much more like aviation usage than tractor pulling, or tractor dirt track racing. Picture an aluminum jon boat with 3 guys, and a load of decoys running flat-out for 10-15 miles to THE SPOT from the nearest launch ramp. Expect big throttle bodies to use with the EFI, better rods, better valve trains, etc.
This is not to say that development on the Kohler CH750 (their mid-sized engine, they also have a Big Block, see TiPi's build thread for an overview of the various classes of engines from the major manufacturers.) is dead. It's still the favorite of the tractor pullers, and there are 2 different brand new CNC hemi heads for this engine, for example (Midwest Super Cubs and Zach Kerber Engineering).
There has been a lot of useful discussion on other recent threads under this forum heading, including on some of the deficiencies of the Kohler. I've also asked the Admins for separate discussion area for Small Industrial V-Twins. And this video by Lonestar Hovercraft compares 3 different brands of roughly 25 HP engines, with a slight win for Kohler http://www.bing.com/videos/search?q=lone+star+hovercraft+briggs+kohler+predator&&view=detail&mid=DFF894FCC0F6EF74E8D8DFF894FCC0F6EF74E8D8&&FORM=VRDGAR&ru=/videos/search?q=lone+star+hovercraft+briggs+kohler+predator&FORM=HDRSC3