Looking for some advice from the boat building and renovating crew... the "fleet" currently has two South Bay Boats (many posts on the site ref. these craft), one of which has a ca. 1982 Evinrude 15HP short shaft that has been on it since I bought it new. At 73 pounds, it gets the job done, but no speed records. The second boat (1982) needs to be powered and I am seriously considering going with one of the long tail mud motors due to the large number of blinds around here that suffer from low water and high mud. The question is, how big a deal would it be to reinforce/modify/replace the current transom and sponson arrangement on the South Bay to allow it to handle a mud motor of up to 150# in weight? Any issues with the boat itself for mud motor use? I can always default to an outboard if this is a non-starter, but it seems like it is something to consider to maximize flexibility in the years ahead. Thanks for any advice!
Question ref. mud motor vs. outboard (weight)
- Thread starter R T Brinn
- Start date
Before you do any modification, I would encourage you to talk to a mud motor owner/operator and ask them what they don't like about their motor. Aslo, how much open water do you normally transit prior getting into the flats? Most of the boats I have seen running them don't do well in anything other than flat water conditions...
Do not put a mud motor on a south bay duck boat. That hull is not made to work with a MM. You think that boat is slow with a 15hp outboard, try stickinging a long tail on there. If you want a mud boat, sell the south bay and buy a mud rig. Or keep it and buy a mud rig if funds permit, but you will be seriously disappointed if you try to run a MM on that hull.
Ray
Well-known member
An option to try first is a heavy duty transom lift/jack to get the prop up behind the boat rather than down below the hull. With the sponsons there will be a tall pool of water in there at slower speeds and that will feed the prop and keep the cavitation plate down in the water. You will not be able to go very fast but will be able to put put into shallower water.
Setting the motor back on the jack/lift can significantly alter the performance of the motor, and the water the prop will be in will be slightly dirty from coming from under the hull. This will effect top end performance rather than low end for the shallow water.
Setting the motor back on the jack/lift can significantly alter the performance of the motor, and the water the prop will be in will be slightly dirty from coming from under the hull. This will effect top end performance rather than low end for the shallow water.
Cody Williams
Well-known member
I'm not sure how the transom is built into those boats but mud motors do put a significant amount of torque on the transom. What HP are you thinking of going with? I know of a few companies that build longtails in the 7hp range that weigh around 70 or 80lbs. If you go up to a 13hp you are talking around 130-150lbs or so. I don't know if the South Bay boat is a displacement hull but if it is you might not have good luck with a mud motor. If you can brace the transom up enough you might have good luck with a smaller mud motor but you won't be going very fast. Have you run a longtail before? There is definitely a learning curve to driving them but they are a lot of fun.
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I have a long tail mud motor on my 12' AA Wigeon a displacement hull and I opted for that type of power for several reasons. Primary reason was simplicity. A long tail kit motor is so simple most people can tear down and rebuild in no time and without special tools or training. Spare parts are cheap and can be kept on hand for repairs in a pinch-has not been the case yet. The power head is a horizontal shaft lawn mower motor and is once again a breeze to work on or throw it away and start over in the case of a 7 hp motor since they can be had for under $100-again not the case yet. Finally almost as important a factor in my decision was the shallow water that plagues so much of the area I hunt and I have run this motor in 3 inches of water, not like on tv but making headway speed.
I am not into speed in the cold and dark and just assume putt along to get there and back. What's the rush? Extra power is nice and necessary in rough water but in my old age I pick my days and have more fun on bluebird days than when it is rough.
While my haunts are the shallows I do cross some channels and open water, however, I limit my exposure due to small craft, payload and engine type. As you can see below with my small boat with a small load of decoys, I usually haul 18-24 more, I am weighted down and under no circumstances should I be on plane with a load and loading of this type. It will not get you on plane and my AA will only get up on plane with the motor when I am empty and alone.
Don't be decieved by the picture the motor from end to end is around 11' long.
Final consideration is the operation of the motor. They do not operate like an outboard and you will not want to find yourself at a crowed ramp and an eight foot shaft with a spinning prop around others. Drawbacks are: 1-no neutral 2-long shaft can be awkward in tight spots 3-no trim or lock on motor so it is always vertically live 4-loud 5-slow on non mud boats 6-you will need some kind of tether in the boat to tie off the tiller arm so the prop is out of water when starting-you need to remember that the resistance of water bogs down the motor when trying to start a submerged prop 7- larger motors can be a bear to start in cold with a pull start since the grease in the coupling gets stiff and prevents the motor from turning over so you will need an electric start that is somewhat defeating of my purpose of keep it simple 8- picking up decoys with the longtail running in deep water is very interesting to say the least and you will find yourself setting anchor and pulling decoys within poles reach and then resetting anchor until all picked up 9-vibrations in the tiller arm 10-it is a work out until you figure out the tricks of running the motor 11- motor gets most of its torque from being submerged deep and as you pick up speed you can raise the prop and run it just below surface without loss of speed so if you are in the shallows you will not be able to get up and go fast or faster.
I have an outboard on my big boat for big water and enjoy both tools in their element.
I am not into speed in the cold and dark and just assume putt along to get there and back. What's the rush? Extra power is nice and necessary in rough water but in my old age I pick my days and have more fun on bluebird days than when it is rough.
While my haunts are the shallows I do cross some channels and open water, however, I limit my exposure due to small craft, payload and engine type. As you can see below with my small boat with a small load of decoys, I usually haul 18-24 more, I am weighted down and under no circumstances should I be on plane with a load and loading of this type. It will not get you on plane and my AA will only get up on plane with the motor when I am empty and alone.
Don't be decieved by the picture the motor from end to end is around 11' long.
Final consideration is the operation of the motor. They do not operate like an outboard and you will not want to find yourself at a crowed ramp and an eight foot shaft with a spinning prop around others. Drawbacks are: 1-no neutral 2-long shaft can be awkward in tight spots 3-no trim or lock on motor so it is always vertically live 4-loud 5-slow on non mud boats 6-you will need some kind of tether in the boat to tie off the tiller arm so the prop is out of water when starting-you need to remember that the resistance of water bogs down the motor when trying to start a submerged prop 7- larger motors can be a bear to start in cold with a pull start since the grease in the coupling gets stiff and prevents the motor from turning over so you will need an electric start that is somewhat defeating of my purpose of keep it simple 8- picking up decoys with the longtail running in deep water is very interesting to say the least and you will find yourself setting anchor and pulling decoys within poles reach and then resetting anchor until all picked up 9-vibrations in the tiller arm 10-it is a work out until you figure out the tricks of running the motor 11- motor gets most of its torque from being submerged deep and as you pick up speed you can raise the prop and run it just below surface without loss of speed so if you are in the shallows you will not be able to get up and go fast or faster.
I have an outboard on my big boat for big water and enjoy both tools in their element.
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noweil Mike
Well-known member
I run a longtail mud motor on a welded Go Devil aluminum hull with a good grab bar where it is to shallow to run an outboard. I don't want a fiberglass hull plowing mud, sand and stumps. I would rather run an outboard any day over my mud motor but if I need a mud motor, I'm hanging it on a hull that is bullet proof. Not something I have to beef up or that I might knock a hole in.
Thanks to all for the feedback and the calls. Decided to defer the mud motor purchase (to go with an aluminum boat procurement somewhere down the road) and just upgun to the 20HP Suzuki. The PortaBote people are running an in-the-box, shipped to your door with no tax Suzuki deal that beats anything I have been able to find anywhere nearby, so here we go! Sale runs through the 17th of March for those that are interested. Thanks again -- this is a great site!