Why overpower this fishing kayak with a 6 hp outboard motor?
Earlier this year, Kenny One-Shot Tracy outfitted his W500 kayak with side flotation and a 6 hp Tohatsu outboard motor, and showed it going at 13 mph. This was intriguing, and several months later, after we came up with the W570 series for offshore fishing, we wanted to test it with a similar motor.
A W kayak weigh 60 lbs and it’s rated for 2-3 hp motors, so it goes without saying that using it with a 6 hp motor means overpowering it, since these motors are rated for moving boats up to 3,000 lbs, that is 50 times heavier.
However, testing and experimenting are part of any Research and Development (R&D) process, and we try as much as we can to test our products under various conditions in order to better understand possibilities, problems, and hazards, and inform our clients about them, so they have more options to choose from, and can make better decisions.
Tohatsu America showed interested in this project and cooperated with us through their dealer Steve’s Marine in Rhode Island, and we got the 6 hp Tohatsu motor (20″ shaft) in late October.
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Motor weight and handling considerations
Although the 6 hp (20″ long shaft) Tohatsu is a sophisticated outboard motor, it is relatively lightweight for its class. However, at 59 lbs it still weighs twice more than the 2-2.3 hp Honda outboard that we’ve routinely used so far. This additional weight was our first concern, and we wanted to experience what it means for a W kayak angler who uses such a motor.
We found the weight difference to be noticeable, but not a major issue – It’s possible to carry such a motor over short distances, whether on its own or mounted on the kayak. Dragging the kayak on a sandy beach was considerably more difficult, but not a big problem over a short distance.
Lifting the motor into the car wasn’t too hard either.
Transporting the boat in the car
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The boat on the beach and at the dock
Launching is easy both from the beach and from a dock, and the same is true for beaching.
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The motor mount
Kenny reported that his 6 hp Tohatsu outboard had broken a DIY motor mount. Such accidents can be dangerous, so we knew that we had to consider both weight and power. Kenny later reported that his 6 hp motor worked with the TMM 20 motor mount that we had sent him, but we preferred to beef up a TMM 20-15 motor mount with an additional 3/4″ board for its vertical mounting plate, making it 1.5″ thick.
The boat itself
Another concern we had about the 6 hp motor’s weight was how our W570 would take it.
The following pictures show that we had no reason to be concerned, as the boat is pretty much level, and the side flotation modules rest several inches above waterline –
Driving the boat
Driving the boat with the 6 hp Tohatsu / 20″ shaft was easy and convenient.
This outboard motor features a 3 position gear system (Forward-Neutral-Reverse) that’s safer than a centrifugal clutch, and makes it easy to start any time. The fact that this motor is water cooled makes it relatively quiet in comparison with the air cooled 2-2.3 hp Honda.
Access to the motor’s controls is easy and convenient once you slide backward on the saddle all the way to the back of the cockpit.
The inflatable flotation modules stayed above waterline and did not cause splashing.
Load and additional passengers
Although a W kayak can carry heavier loads, we rate these kayaks for a total load of 360 lbs, for both safety and performance reasons. This number includes everything that the boat may carry, from passengers and their personal belongings to fishing gear, an anchor, and last but not least – a motor. With a 60 lbs motor and all the extra accessories that come with the Wavewalk 570, and considering the high speed in which you’re likely to drive, it would be safer to consider the W570 as a one-person motorized kayak, or a solo skiff, if you prefer. This is unless the user is not heavy, and they take a lightweight passenger on board. For example: A driver that weighs less than 200 lbs could take on board a small child weighing 60 lbs, plus some lightweight fishing tackle.
The 6 hp Tohatsu outboard model that we’ve tested features an integral fuel tank that allows it to go for 45 minutes full throttle, but as long as you drive a W570 with it you won’t go over 1/3 throttle since doing so is likely to increase your speed dangerously, unless you’re towing a bigger boat or several kayaks and canoes.
In one occasion, while the boat was going pretty fast, the propeller hit a rock on the bottom of the lake, and got ejected out of the water, as it’s designed to do in such cases. Lowering it back into the water presented no problem. The reinforced TMM 20-15 transom mount didn’t budge, and the inflatable side flotation proved that it’s useful in helping to prevent the boat from rolling (flipping) if it’s tilting strongly as it did following the impact and momentary loss of control that resulted from it.
The role that the inflatable flotation played in that accident emphasizes its importance.
Power and speed
A W kayak outfitted with a 2-2.3 hp outboard can go at 8.5 mph, full throttle, while the same kayak outfitted with a 6 hp Tohatsu motor can reach 13 mph at 1/3 throttle, a speed that for most people makes it too much of a challenge to drive safely. This is where we found that a 6 hp motor wasn’t the best fit for the Wavewalk 570. In other words, overpowering the W570 with such a powerful motor can be hazardous and cause accidents if you drive too fast relatively to your boating skills and/or to water conditions, or if you accidentally accelerate abruptly or even just too quickly for you to safely maintain control over the vessel.
This lightweight craft is no match for the power and torque of such a big engine, and that makes it too ‘nervous’ compared to when it’s outfitted with a smaller and less powerful motor that tks longer to accelerate.
Why you might want to overpower
Having said that, you might like this overpowered configuration if you’re a risk-loving speed fan who enjoys the feeling of danger. It’s your choice, as long as you’re aware of the safety hazards, and you know that the W570 isn’t rated for motors that are more powerful than 2-3 hp.
A more productive way to make use of such a disproportionally powerful motor could be for towing other boats. For example, if you use the W570 as tender (auxiliary service boat) for a bigger leisure craft such as a sailboat, it could tow the mother ship, if necessary, or tow another tender with several passengers and provisions on board (e.g. an inflatable dinghy).
If indeed you’re thinking about such use, make sure the towed craft are properly attached to your W570, and don’t use its handles or eyelets for this purpose.
Similarly, if you go on a camping and fishing trip in which several people take part, your W570 on steroids could tow several kayaks and canoes over long distances, and make life easier for the other members of your expedition.
If you’re thinking about driving up fast rivers, such as in springtime, or on fast tidal rivers, more power and torque may be justified, although it’s hard to imagine cases where a 2-3 hp motor would not suffice for your W kayak. Just remember that fast moving rivers are hazardous, and we recommend neither paddling nor motorizing in them.
Another case in which you could be interested to use a 6 hp outboard motor with your W570 is if you already own a larger boat that you propel with such a motor, and you want to alternate between your W570 and that bigger boat. For example, you may prefer to go fishing on your own in the W570, and take the bigger boat when you fish with your family and friends. If you don’t like to purchase a smaller outboard for your W570, you could try using your 6 hp outboard with it, and see how it works for you. If it does, it could save you the additional expense on a small motor. Just remember to be very cautious with the throttle when the motor is mounted on your W570.
All the above said does not imply that we rate the W570 for use with an outboard motor that’s more powerful than 2-3 hp, because we don’t. We think that using a W kayak with motors that are more powerful than 2-3 hp could be hazardous.
Again, the purpose of this article is to inform people about what using much stronger motors implies, and warn them about problems and dangers associated with such practice.