How to Build a Mud Motor

The mud motor allows boaters to traverse terrain that would otherwise be inaccessible. Learn more about this unique propulsion, and how you can build your own.

How to Build a Mud Motor

The author aboard his Gheenoe powered by a Harbor Freight motor, driving a Small Swamp Runner mud-motor kit. (Dan Armitage/)

A scene from the 1974 James Bond film The Man with the Golden Gun depicts Bond racing through the canals of Bangkok, fleeing from bad guys in a sleek sampan powered by what looked like an F150 engine sprouting a long, straight shaft ending in an open, two-blade prop known as a Thai longtail. Bond ended the chase by cutting his pursuer’s boat in half with his own longtail buzz-saw propeller.

I was in college when that movie came out, and I’ve pined for such a motor ever since. When I stumbled across an ad for a DIY kit-built longtail, I talked to Steve Cadwell, manager of SPS North America, which manufactures the parts in Thailand and offers what some refer to as “mud motor” kits under the Swamp Runner name in the US and Canada.

“A fellow by the name of Songsak Sriprasertying of Bangkok is the original inventor of the coupler used in Thai longtails and first began manufacturing the kits 57 years ago,” Cadwell explains. “He was a machinist and recognized the need for a boat motor that rural farmers could afford to transport huge loads of rice down shallow rivers and canals to market. Sriprasertying developed an affordable kit that, when attached to a small, air-cooled engine, creates a shallow-running outboard.”

They’re inexpensive, simple and durable. For trailering, just turn the mud-motor drive backward.
They’re inexpensive, simple and durable. For trailering, just turn the mud-motor drive backward. (Dan Armitage/)

Lifelong boater Jon Dobbs became acquainted with SPS—run by Sriprasertying’s sons—two decades ago while traveling in Thailand. He founded SPS North America and began importing the kits for sale in the continent.

“As a poor hillbilly kid,” Dobbs reminisces, “I couldn’t afford a boat to hunt and fish out of, so I had to settle for whatever waterfowl I could take hunting from shore. Those memories motivated me to make boating possible for folks who couldn’t otherwise afford it.”

Dobbs moved to Florida in 1986 and went to work for the Florida Marine Patrol for the next quarter century. He holds a USCG 50-ton Master Captain’s license and has piloted everything from airboats to 1,200 hp offshore interceptors while in pursuit of poachers and smugglers. Managing a fleet of watercraft made him keenly aware of how expensive boating had actually become.

“Keeping a conventional outboard engine running in this day and age can be very expensive,” he says. “The cost simply makes boating too expensive for many folks.”

Swamp Runner mud-motor kits range in price between $399 and $749, and are available for engines ranging between 2 and 40 hp. To see the full lineup, view videos of how to drive with them, or purchase a kit, visit mudmotorkit.com.
Swamp Runner mud-motor kits range in price between $399 and $749, and are available for engines ranging between 2 and 40 hp. To see the full lineup, view videos of how to drive with them, or purchase a kit, visit mudmotorkit.com. (Dan Armitage/)

Besides cost, a big benefit—and why SPS engines earned the mud-motor moniker—is that you don’t even need water to run in, if you’re on a soft mud bottom, have enough engine torque to match your payload, and the prop can get a bite.

In Southeast Asia, where longtail racing is popular and an SPS kit holds the world mud-motor speed record of 93 mph, the units are coupled to everything from small-block V-8s to 480 hp Hino diesel-truck engines cranking out 4,700 foot-pounds of torque. In North America, where demand is for smaller motors, SPS offers kits for engines up to 40 hp. In fact, one of its most popular kits, the Mini, is designed for boats rated to accept 2 hp engines.

Cadwell says he’s seen the Minis on everything from one-person john- and poke boats to concrete-mixing tubs that hunters and anglers use to cross shallows, where no other engine can take them.

For my use, to power a well-used 15-foot Gheenoe I picked up on Craigslist, he recommended the Small Swamp Runner kit for engines 5.5 to 7 hp. Perusing the recommended engine list for that kit model, I noted a 6.5 hp Predator 212cc horizontal shaft offered by Harbor Freight, and waited until it went on sale for $99 to purchase the simple, single-cylinder, air-cooled four-stroke. At that point, with the $449 cost for the Small Swamp Runner kit, I had $550 invested in the project and couldn’t wait to get on the water with it. A 6 hp outboard costs about $1,500.

It didn’t take long. A buddy and I had the kit and motor coupled and the longtail hanging off the Gheenoe’s transom before lunch. I chopped through dense hydrilla mats, bumping over half-sunken logs and getting double takes from fellow boaters that afternoon. While it is louder than most outboards, its cost and utility are unmatched. I’ll use the super-shallow-running rig to access the upper reaches of Great Lakes tributaries to catch steelhead and shoot ducks in the fall, and for scooting through South Florida backwaters during winter.

Step-by-Step Instructions

Here are the major steps in the DIY Mud Motor project:

The Swamp Runner kit and Predator 212 cc horizontal shaft motor from Harbor Freight ready for assembly.
The Swamp Runner kit and Predator 212 cc horizontal shaft motor from Harbor Freight ready for assembly. (Dan Armitage/)Attach the coupler shaft to the engine PTO shaft motor prior to connecting the coupler housing.
Attach the coupler shaft to the engine PTO shaft motor prior to connecting the coupler housing. (Dan Armitage/)Fit the gimbal bracket shaft into the transom bracket.
Fit the gimbal bracket shaft into the transom bracket. (Dan Armitage/)Insert the tiller handle into the mounting rings mounted on both sides of the engine base to allow left or right hand steering.
Insert the tiller handle into the mounting rings mounted on both sides of the engine base to allow left or right hand steering. (Dan Armitage/)Secure the engine in the base bracket.
Secure the engine in the base bracket. (Dan Armitage/)Install the oil sensor and throttle linkage to the engine and kill switch, cable and squeeze-style lever to the tiller.
Install the oil sensor and throttle linkage to the engine and kill switch, cable and squeeze-style lever to the tiller. (Dan Armitage/)Insert the engine shaft into coupler, align and tighten with two wing bolts.
Insert the engine shaft into coupler, align and tighten with two wing bolts. (Dan Armitage/)Bolt the double-bladed aluminum prop to the threaded end of the engine shaft.
Bolt the double-bladed aluminum prop to the threaded end of the engine shaft. (Dan Armitage/)Add fuel, oil and test-run the air-cooled engine.
Add fuel, oil and test-run the air-cooled engine. (Dan Armitage/)Secure it to the boat’s transom and seek out a swamp.
Secure it to the boat’s transom and seek out a swamp. (Dan Armitage/)


Source : Boating Magazine More   

What's Your Reaction?

like
0
dislike
0
love
0
funny
0
angry
0
sad
0
wow
0

Next Article

Boating Summer 2021 Trends

In the era of the coronavirus pandemic, finding ways to recreate outdoors has become an important survival tool. Last year, the boating industry saw a record number of new boat owners on the water. Both new boaters, and seasoned boaters alike, changed their habits to social distance naturally while making the most of their love for the recreational outlet. According to a survey of 3,500 boaters by Sea Tow Services International, we can expect this trend to continue into the 2021 summer season.

Boating Summer 2021 Trends

In the era of the coronavirus pandemic, finding ways to recreate outdoors has become an important survival tool. Last year, the boating industry saw a record number of new boat owners on the water. Both new boaters, and seasoned boaters alike, changed their habits to social distance naturally while making the most of their love for the recreational outlet. According to a survey of 3,500 boaters by Sea Tow Services International, we can expect this trend to continue into the 2021 summer season.


Sea Tow Huntington, N.Y., on station ready to render assistance to boaters. (Courtesy Sea Tow/)

Pandemic-influenced boating behavior:

  • 52% of boaters surveyed anticipate their boating activity to increase this summer compared to last.
  • 20% cite the pandemic as the reason for extending their boating season again in 2021.
  • 24% plan to vacation on/by boat (versus other forms of travel) because of the pandemic.
  • 35% plan to use their boat primarily for cruising near their home.
  • 16% upgraded to a larger boat in 2020 or plan to do so in 2021.
  • 52% plan to use their boat primarily for fishing (65% in-shore / 30% off-shore / 5% freshwater).
  • 30% have found it more difficult to find dockage and/or marina space.

Our member survey has typically been a very strong indicator for seasonal recreational boating trends,” said Kristen Frohnhoefer, President of Sea Tow. “Last year, Sea Tow saw a 34% increase in requests for on-water assistance in the summer of 2020, and our nationwide network of captains are anticipating another busy season for 2021.”

With the sale of a record number of new boats in over a decade and an influx of new boaters, Sea Tow noted that in 2020 owners of new boats were 142% more likely to need ungrounding services, 108% more likely to need fuel delivered to them and 11.2% more likely to need a battery jump. Alternately, new boat owners are 22% less likely to need a tow.

Read Next: On Board With: Scott Collins

“These numbers are very interesting,” Frohnhoefer says, “they reflect the fact that new boaters are not yet familiar with things like shifting sandbars and hard to navigate channels, or how to manage their fuel, like their more seasoned counterparts – which is getting them into trouble and causing them to call us for assistance. But likewise, these stats demonstrate what we’ve been saying all along – that when it comes to new boats, on-water assistance typically is needed due to user error, not mechanical failure, as newer boats and engines are more reliable than ever before.”

With the number of new boaters recreating on the water, the need for boating education has never been more important. 69% of boaters surveyed are looking for more advice on local navigational assistance, mishap prevention and general boating basics.

“2021 is sure to be another banner year for boating,” says Frohnhoefer, “with the unofficial start of summer only a few weeks away, we’ll find out real soon if these trends for recreational boating activity are in fact here to stay.

Sea Tow performs a variety of duties in addition to on-water assistance.
Sea Tow performs a variety of duties in addition to on-water assistance. (Courtesy Sea Tow/)

About Sea Tow Services International, Inc.

Sea Tow Services International Inc., better known as Sea Tow®, has been the innovative and premier leader of on-water assistance since 1983. Servicing the United States, Puerto Rico and the U.S. Virgin Islands, members are provided with a 24/7 direct connection with Coast Guard-licensed captains. The pioneering concept, founded by Captain Joseph Frohnhoefer, was established in Southold, NY when the United States Coast Guard ceased response to non-emergency assistance calls.

In addition to on-water assistance, the franchise network handles salvage and recovery missions, and responds to natural disasters, environmental hazards and oil spill cleanups.

Visit seatow.com to learn more.

Source : Boating Magazine More   

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.