This short movie shows Captain Larry Jarboe driving his S4 kayak skiff powered by a 9.8 HP Tohatsu outboard motor with a 6’3″ 260 lbs passenger on board, in a narrow and winding mangrove creek. The total payload carried by his S4 is over 500 lbs. The S4 is perfectly stable and maneuvers easily despite the high speed and heavy load.
Larry is driving seated side-saddle, dinghy style, with both feet in the left hull and facing sideways, and his passenger rides the saddle PWC style, with a foot in each hull, and facing forward.
“Kayak”??… This is likely to be the last thing that comes to mind of anyone watching this movie, but indeed, the S4, like all Wavewalk’s patented catamaran boats, is officially designated as a kayak, not just because of its light weight (98 lbs) and high performance as a paddle craft, but mainly thanks to certain design features required by law. Skiff?… The kind of performance seen in this movie is not what you’d expect from a skiff or skiff by name. Wavewalk likes to bring forward the S4’s performance as a skiff, namely a fishing boat for flat water, but there’s no flat water to be seen in this offshore movie… far from that! PWC?… Such comparison would have been more appropriate if we used wheel steering instead of direct steering with the tiller, and possibly an even more powerful motor than the 9.8 HP Tohatsu that features in this movie. Nevertheless, the movie conveys some of the action and excitement associated with Personal Watercraft (PWC), sometimes referred to as jet-skis.
PWC stability at high speed
This video shows the Wavewalk S4 powered by a 9.8 HP Tohatsu outboard motor, driven at full throttle, offshore, in choppy water and waves. It demonstrates a performance level that’s new in the world of small boats and watercraft, including both unrivaled speed and stability that enables stand-up driving and wave-hopping that one expects to find only in Personal Watercraft (PWC).
Perfect balancing and ergonomic saddle seat
The Wavewalk design and PWC have one feature in common, which is their similar saddle seats that deliver the best balancing capabilities to the driver and passengers. But the advantage of the saddle seat doesn’t end there – The saddle also allows the driver and passengers’ legs to act naturally as powerful and effective shock absorbers that protect their backs from the unwanted impact of the constant leaps and bounds, and high speed clashes with waves.
Being officially designated as a kayak, the S4 delivers these capabilities in a paddling mode too, although at much lower speeds…
A most seaworthy small boat
The performance seen in this video is not the kind of performance that flat-bottomed boats such as Jon boats or skiffs can deliver. The S4 is seaworthy, while these traditional small fishing boats aren’t. What cannot be well perceived from watching this movie is the fact that the S4 is dry too – Frontal clashes with waves do not let water into its hulls, and the only time when spray gets in is when the boat is hits a wave with its broadside. Even then, very little water gets inside.
Shooting this video
The cameraman was Captain Larry Jarboe, standing on the deck of his fishing boat, the Line Dancer, that was anchored in the same choppy waters as the S4 is seen going in. The Line Dancer was constantly bouncing and tilting, which made it particularly difficult to shoot video of another, distant and fast moving small boat. Larry used a Nikon Coolpix 900 digital camera with a powerful x83 optical zoom lens, in an auto-focus mode, but since placing this camera on a tripod would have been useless under these hectic conditions, Larry’s sea legs were the decisive factor that helped produce the video footage for this movie.
The White Knight – Larry’s workhorse S4
The boat in this movie is Larry’s personal S4, dubbed the White Knight. Larry offers fishing and diving tours in Key Largo, and it is this boat that he uses in these trips, and on a daily basis. The White Knight features a base for a diving ladder at the bow, and foam boards on its sides, since Larry sometimes uses it to side-tow two other S4s,each attached to a different side of the White Knight.
The White Knight is powered by a 9.8 HP 2-cycle Tohatsu outboard motor, and Larry recently clocked 17 mph with it, which is a world speed record for kayaks.
Driving the S4
The S4 operator in this movie is 56 years old, and not in great shape. An athletic driver half his age would have probably driven the S4 more aggressively and spectacularly, but that tired-looking, gray haired driver adds a feeling of reality to the video, or so we hope…
Another important trade-off that you should be aware of is related to propellers: High pitch propellers are designed to deliver more speed and less torque (thrust, push force), and they work best with lightweight boats such as the S4, while low pitch propellers are designed to move bigger and heavier boats at lower speeds, but they should not be used with lightweight boats such as the S4, since they might make the motor run at a too-high RPM.
Outboard motors manufacturers’ websites say that (quote) “UNDER NO CIRCUMSTANCES SHOULD YOU EVER USE A PROP WHICH WILL ALLOW YOUR OUTBOARD TO OPERATE ABOVE THE OUTBOARD’S RECOMMENDED MAXIMUM RPMs“. This means that you should avoid using propellers designed for use with very heavy boats, namely propellers in the low-pitch range.
Note that 20″ long (L) propeller shaft motors typically ship with propellers that are not necessarily optimal for very lightweight boats such as the S4. For example, the 6 HP 20” long (L) outboard from Tohatsu often comes with a medium range 8 pitch propeller, which is fine, but mounted on the S4, such a motor could drive the S4 12% faster if outfitted with a 9 pitch propeller.
Propeller pitch information is available on outboard manufacturers’ websites.
Since the S4 is a very lightweight boat, you should preferably outfit the outboard motor for it with the highest pitch propeller available for it.
Diameter – Don’t try to use a propeller from a small outboard with a bigger outboard, or vice versa.
Hydrofoils (“Fins”) for the outboard
A hydrofoil is an add-on device attached to the outboard motor’s propeller shaft (a.k.a. “leg”). The hydrofoil generates lift at the boat’s stern – The higher the speed the more lift. Hydrofoils can help correct various problems that a powerboat may have, but the S4 has no problems that require correction. This said, hydrofoils help keep the bow down and the stern higher, and a boat that travels this way, namely in a more level position, planes better than if its bow was higher and stern lower. Therefore, outfitting your S4’s outboard motor with a hydrofoil device can result in higher speed on flat water when driving in a solo mode, that is without a passenger in the front. The downside of using a hydrofoil is that when driving with a lowered bow in the ocean, the boat might generate more spray as it bumps into big waves, especially if there’s a passenger in the front. Bottom line: If you like driving solo at high speed on flat water, consider adding a hydrofoil, and if you need to drive in big waves with the hydrofoil on, trim the motor less aggressively by using its trim angle adjustment rod, or knob, especially if you have a passenger on board whose presence also works to lower the bow.
SMALL PORTABLE OUTBOARD MOTORS
For the S4, small size means a highly portable but under-powered outboard motor.
2 HP outboards
Outboard motors in this class weigh around 30 lbs, which makes them fully portable even for a user who’s not very strong. A 2 HP motor can propel an S4 skiff with one person on board at speeds up 8 mph, even in choppy water. This speed would decrease as the boat is required to carry more passengers on board. S4 owners who tested such motors with their S4 skiff reported that the boat felt under powered, which means that they felt like going faster, but the motor lacked the power required for this. For this reason 2 HP motors are not popular with S4 users. Another reason for their lack of popularity is the fact that being air cooled makes these small motors noisier than bigger, water cooled motors.
Propeller pitch – The Honda 2.3 HP comes with a 4.75 pitch propeller
MEDIUM SIZE PORTABLE OUTBOARD MOTORS
For the S4, a medium size outboard motor means powerful enough but still portable. Motors in this 3.5 HP to 6 HP range are the ones we recommend for most users.
3.5 HP outboards
Outboard motors in this range weigh around 40 lbs, which makes them still portable, but less so than 2 HP motors. A 3.5 HP motor can propel an S4 skiff with one person on board at speeds up to 11 mph, even in choppy water, and it can propel the boat at 8 mph with three passengers on board in moving water. This size motor is popular among S4 and W700 users, as it offers a good trade-off between power and weight for people who must lift the motor or carry it by hand over long distances. These motors are also less expensive than bigger ones.
Propeller pitch – For their 3.5 HP motor, Tohatsu recommends either the 7 pitch (Plastic) or 6 pitch (aluminum) propellers, for lightweight boats such as the S4 (under 500 lbs). We say get the 7 pitch propeller, unless you think that you need the more durable aluminum propeller.
6 HP outboards
Outboard motors in this range weigh around 60 lbs, which makes them portable only over short distances, and not for everyone. A 6 HP motor can propel an S4 skiff with one person on board at 17 mph, and it can propel the boat at 12 mph with three passengers on board. 6 HP is the second most popular motor size among S4 users.
Propeller pitch For their 6 HP outboard used with lightweight boats up to 500 lbs (such as the S4), Tohatsu recommends their 9 pitch propeller. The 8 pitch propeller would work too, especially if you intend to have the boat fully loaded, so that it would weigh over 500 lbs in total.
BIGGER OUTBOARD MOTORS
8 HP to 10 HP outboard motors are too heavy to be carried by hand, and they may be too powerful for inexperienced drivers to use safely. However, some of them come with electric start instead on manual start, which is a nice feature. They also come with an alternator that can serve to power small electric devices on board.
8 HP outboards
Outboard motors in this class weigh between 65 and 80 lbs. At such weight, these motors can no longer be considered as portable, and the main reason to use them is the fact that are offered with electric ignition, which eliminates the need to start them by pulling a cord. People who like driving at high speed may prefer these motors to less powerful ones. The S4 outfitted with an 8 HP motor performs well in choppy water, but it could feel over powered for an inexperienced driver, which should avoid using such motors with their S4. Heavy users may benefit from driving with a U-jointed tiller extension, in order to move some weight forward from the stern towards the middle of the boat.
Note that these bigger motors don’t come with an integrated fuel tank, but this isn’t necessarily a problem, since external fuel tanks can fit inside the S4’s hulls.
9.8 HP and 9.9 HP outboards
We tested the S4 with a 9.8 HP Tohatsu and a 9.9 HP Yamaha outboard, and it worked well. Practically, this class of heavier and more powerful motors offers no advantage over smaller motors unless you’re a speed fan, and you’re also capable of driving small boats safely at such speeds. To those who want to take the risk of overpowering their S4 with such big motors, we recommend reinforcing the mounting plate.
This video shows an S4 powered by a 9.8 HP Tohatsu motor filmed from the deck of an S4 powered by a 5 HP Tohatsu motor:
Currently, the S4 is the world’s fastest designated kayak. The 17 mph kayak speed record was achieved by Captain Larry Jarboe, of Key Largo, Florida, in his S4 outfitted with a 9.8 HP Tohatsu outboard motor.
We recommend that inexperienced drivers avoid using high power motors with their S4. Instead, they should pick a motor within the 3.5 HP to 6 HP range.
OUTBOARD MOTOR BRANDS
After years of testing motors and getting input from our clients, we can recommend all Japanese brands, namely Honda, Suzuky, Tohatsu and Yamaha. Mercury is a Tohatsu brand, and the small, portable motors offered by Evinrude are made by Tohatsu. Motors from all these brands are good, and your decision about which motor to use with your S4 should be based on factors such as price, weight, features, availability, warranty, etc.
A kicker motor is a name given to any outboard gas motor used on a big boat for trolling, or as a spare motor, and for positioning and driving sailboats over short distances when sailing them is not possible. Being used on bigger boats, kickers often feature a 20″ long (L) shaft, which is the right size for the S4, but the propellers used with them are typically low-pitch models that are not optimal for lightweight boats such as the S4. If you buy a kicker, check its propeller, and if it’s not a model with the highest pitch that the manufacturer recommends for lightweight boats, replace it with such a propeller.
MUD MOTORS – SURFACE DRIVES
Most motors feature a surface drive, and they offer a huge advantage to people who want to drive in very shallow water, mud, water with many underwater obstacles, and water with plenty of vegetation. Mud motors are bulkier and heavier than regular outboard motors of similar power.
3 HP motors
A 3 HP long tail mud motor weighs about 40 lbs, and as such it’s portable. It works well both in flat water and streams, although not very fast ones. The S4 can definitely use much more powerful motors.
6.5 HP motors
A 6.5 HP mud motor weighs around 80 lbs, and it’s not portable. The reasons you’d want to use such a motor instead of a regular outboard of similar power are if you need to go in very shallow water (skinny water) and mud, and if you fish or hunt in water with plenty of vegetation and underwater obstacles. The S4 performs very well with a such a mud motor. We do not recommend using less powerful mud motors because typically, these motors require more power than regular outboard motors do.
Electric outboard motors
Typically, electric trolling motors are not powerful, and they are designed to propel heavier boats than the S4 (e.g. bass boat, skiff, Jon boat) at a very low speed, namely trolling speed. This type of application requires high thrust (small pitch) propellers, and it’s also the reason why trolling motors are rated in thrust units (lbs) and not in horsepower (HP or KW) – When you buy such a motor, your primary interest is how big (heavy) a boat it can move, and not at what speed.
Some electric trolling motors are described by their manufacturers as “outboard motors”, namely comparable in performance to small outboard gas engines. If you’re interested in such electric motors, we recommend comparing apples to apples namely power units to power units, and not power to thrust, which is meaningless. Remember the laws of physics, and apply the formulae for Kilowatts to Horsepower conversion, which are:
This article is an attempt to answer some questions that Wavewalk skiff owners ask in the process of choosing an outboard motor for it –
Short shaft or long shaft?
We definitely recommend using outboards that feature a long (20″) propeller shaft, and for multiple reasons, which are discussed in this article entitled Outboard motor propeller shaft length for Wavewalk fishing kayaks and boats » We recommend not to be tempted by the availability and lower price of 15″ short shaft outboard motors, because such motors don’t fit the W700, and using one would never produce optimal results, even for a highly skilled individual with a lot of experience in boat outfitting.
Here is a list of long (L) 20″ shaft outboard motors currently available in the 2 to 6 horsepower range, and their HP rating:
Water cooled motors are quieter but heavier than comparable air cooled motors. The only motor featuring on the above list that’s not water cooled is the Honda 2.3 HP. It is very lightweight, and works very well, but being air cooled makes it considerably noisier.
Note: Outboard motor manufacturers recommend flushing the motor’s cooling system with fresh water after every trip in saltwater. It’s possible to flush an outboard with a garden hose outfitted with a special adapter.
4-Cycle or 2-Cycle engine?
Nearly all new small motors on the market are 4-Cycle (4-stroke) and not 2-Cycle (2-stroke). The advantage of the 4-Cycle system is twofold –
The motor runs on regular fuel, and there is no need to mix it with oil.
A 4-Cycle motor is cleaner, namely it emits far less stinky fumes than 2-cycle motors do.
Some experts argue that for the same displacement of its combustion chamber (cc, volume, size), a 2-Cycle engine in more powerful than 4-Cycle one, but we think that convenience and fresh air are more important.
electric or gas?
Many Wavewalk owners outfit their W500 and W700 with electric motors in the 30 to 50 lbs thrust range, and some go as far as 70 lbs thrust. They use their electric kayaks and skiffs for assisted paddling, recreation, touring, trolling, fishing, snorkeling, etc., but we prefer not to include electric motors in our list of “real” outboard motors for two reasons, which are:
Power – Although some small electric motors are offered as “outboard motors”, just looking at their basic, objective power rating makes us think that they are too weak. Kilowatts to Horsepower conversion: 1 KW = 1.34 HP, and 1 HP = 0.745 KW. Consequently, an electric motor can work well on flat water and at a moderate speed, but not necessarily in adverse conditions, namely strong current, strong wind, etc.
Range of travel – A gallon (3.8 liter) of fuel costs a few dollars, and it’s enough for a typical small outboard motor to run for 4 hours at a high RPM, or an entire day at a lower RPM. You can refuel a small outboard’s built-in fuel tank when you’re on board your Wavewalk®. You can take several gallons of fuel with you on a long camping trip, and you can buy more fuel almost everywhere, while recharging an electric motor’s battery can take half a day. Therefore, gas outboard motors offer a reliable and convenient solution whose price / performance ratio is unbeatable by any electric motor available today.
All small outboard motors listed above are considered to be Portable. However, between the 29 lbs of the 2.3 HP Honda and the 59 lbs of the 6 HP motors there is a considerable difference, if you need to carry the motor by hand over a distance.
The shallow water position
Most of the small outboard motors listed here offer to lock their propeller shaft in an intermediary position between the vertical (down) and horizontal (up) positions. In this intermediary, slanted position, the propeller drafts less than in the vertical position, and this allows for driving the boat at a moderate speed in very shallow (‘skinny’) water. Therefore, if you’re looking to fish in skinny water, we recommend that you look for this feature.
gear shift lever
Most outboard motors on our list feature a gear shift level, and this is a good thing, because the alternative is a centrifugal clutch that lacks an absolute neutral position. The absence of a full neutral gear can make starting the motor a little tricky, if you’re a beginner. Our preference goes to the outboard motors that feature the gear shift lever at the front, rather than on their side. The frontal position makes it easier for the driver to access the lever whether the motors points left or right, and even if the driver is facing forward.
built-in fuel tank
All the above listed outboard motors come with a built-in (integrated) fuel tank, and this is a convenient feature considering the alternative is to have a fuel line run from a separate tank to the engine. When you operate such a small craft as a Wavewalk, simplicity becomes increasingly important.
The propellers that come standard with these outboard motors fit Wavewalk’s kayaks and portable skiffs. Typically, these motors propel much heavier boats, which is why the propeller’s diameter and pitch which determine output in terms of speed and torque are of no real consequence to the owner of a Wavewalk under normal conditions.
price and brand
All the brands listed above are known to produce quality motors, and in fact some of them produce motors for others. For example, Mercury is a Tohatsu brand. This is to say that we see no reason to pay more for a particular name brand, and we recommend to consider only the motor’s technical attributes, and its price.
HP rating – can i overpower my skiff?
6 HP is the absolute maximum for which the W700 is rated, and this is only for its RIB model. Overpowering your Wavewalk can be hazardous, and if you use the wrong motor mount you’d be calling for trouble. This said, if you happen to own a 20″ shaft 5 HP motor and your W700 is rated for a 4.5 HP motor, you can keep your motor, and you won’t necessarily have to get a new one. Similarly, if your W700 is rated for up to 4.5 HP and you found a nice 4 HP that you like, you’d be fine with it.
If you choose to make a DIY mount for an electric trolling motor, chances are that you’ll succeed, since these motors are so weak that they’re not likely to cause trouble. But this is not the case with the gas outboard motors in the range that features on the above list. There are several issues to overcome with motor mounts, and the motor’s weight is the least of them. The main problem is that operating at the end of a 20″ lever, the motor’s propeller generates a great amount of torque, especially at high speed, in rough water and when making sharp turns at high speed. This torque can twist and crack a 4×2 timber, and pull out nails and screws from their place. After having seen motor mounts get broken by outboard motors ranging from 6 to 3.5 HP that were mounted on them, we strongly recommend not to build a DIY motor mount for these motors, and to use only the motor mounts that Wavewalk recommends.
Some of the more powerful outboard motors listed here can be outfitted with an alternator and an AC to DC converter. Note that such accessories cost hundreds of dollars. The electric current produced by this system can be used to power lights on board, or to charge a trolling motor’s battery. Such setups are common in bigger boats (e.g. bass boats) that feature much more powerful motors. Although some Wavewalk owners have outfitted their W700 with two motors (a powerful one for driving and a small one for trolling), we don’t know of anyone who’s outfitted their outboard motor with an electric current generation system.
Why an outboard motor?
Skiffs, Jon boats and other small boats sometime come with other motors, among which are air drives or air motors (large diameter propellers) for running marshes and flats, jet drives (similar to personal watercraft, a.k.a. jet-ski), long shaft mud motors for going in shallow water and over obstacles, and outboard motors that run on propane.
While each of these motors offers certain special advantages, and we’d love to see the W700 outfitted with any of them, as well as with other propulsion systems ranging from sails to oars, and even pedal drives… we think the common small outboards such as we listed here offer the optimal mix of price, performance, reliability, versatility, ease of use, and ease of maintenance – Just think how common are boat dealerships and repair shops that service these motors… And if you know how to use your outboard motor and you take care of it, it’s truly a wonderful thing that you’d enjoy for years, and possibly even decades.
Wavewalk no longer offers this configuration as shown here. Since we now offer 12 ft long (7.25″ diameter) detachable inflatable flotation tubes as part of the W700 RIB , we offer only boats with one pair of regular size tubes (5 ft long / 6.5″ diameter) or one pair of the XL tubes (12 ft long / 7.25″ diameter). We left this page and the RHIB configuration here in order to show yet another configuration that’s possible.
Wavewalk® RHIB – Rigid Hull Inflatable Boat
Before we go any further, the answer to your question is: -“Yes! This boat is great for fishing, for one or two anglers, once you detach the front pair of inflatable tubes, or both pairs, which takes less an a minute.” In other words, the RHIB is simply a Wavewalk® 700 Z model that features an additional pair of inflatable tubes attached in the front. And now that things are a bit clearer, let’s watch this video – Tip: For best quality set your YouTube viewer to 1080 p HD
Why two pairs of inflatable tubes?
Good question! In this video, the front inflatable tubes touch the water on rare occasions, and when they do, they don’t seem to do much. This is because their purpose is to serve as secondary flotation, in addition to the saddle and the rear inflatable tubes. In extreme cases, if the boat tilts very strongly on its side, these extra tubes could help prevent it from flipping. They can also help when the boat goes in bigger waves, since they add buoyancy to the bow, which allows the boat to go over the wave instead of through it. This can help prevent spray from getting into the boat, and make the ride less bumpy. Extra flotation on both sides of the bow can be useful in other cases, such as when the boat is used for work or rescue, when divers climb on board from the water, and when heavy crab traps are hauled in.
What if I don’t want to use these extra inflatable tubes?
Each tube is attached to the boat with two carabiners, and it takes just seconds to detach it. It can be easily stored in the boat while still inflated, and both inflating and deflating it takes seconds, thanks to a user-friendly, wide (1.25″ diameter) inflation valve that saves you the need for a pump.
And what about that transparent spray shield?
The spray shield is attached to the boat with a bungee cord and two hooks. It takes a few seconds to attach or detach it, and once it’s not attached it’s just a flat, lightweight, flexible sheet of plastic that hardly takes any space, and can be easily stored inside one of the boat’s hulls.
What’s a RHIB?
RHIB is the acronym for Rigid Hull Inflatable Boat, also known as RIB (Rigid Inflatable Boat). These motorboats are designed for extra stability and speed, and they come in various sizes. The smaller ones are motorized dinghies that can take a small number of passengers through rough water. RHIB are very popular, and used in a wide range of applications, such as rescue, offshore work, tending bigger boats, diving, etc. Anglers prefer not to fish out of inflatable boats because of the fishing hooks… but this is not an issue with Wavewalk’s RHIB, since its inflatable tubes can be removed instantly.
What’s special about the Wavewalk® RHIB?
Compared to rigid-inflatable dinghies of its size the Wavewalk® is –
More stable: It features a catamaran hull, and a saddle that makes it easier for the driver and passenger/s to balance themselves.
Easier to car-top: Its rigid hull weighs just 80 lbs, and it’s 12’10” (391 cm) long, which makes it easy to lean on the vehicle’s roof before sliding the boat upward.
More versatile: Without the front pair of inflatable tubes it’s a Wavewalk® 700 Z model, which is a great fishing boat for one or two anglers. Without inflatable tubes it’s a nifty motorboat that paddles well, and without the motor it’s hands down the world’s best fishing and touring kayak.
Faster: Videos of this RHIB and other W700 configurations show the unique Wavewalk ‘signature’ in the water – Practically no wake in the front, and a very slender wake at the stern. In this sense, this wake reminds a torpedo moving in the water, and not a boat, especially not a RHIB. Being typically wide and designed to plane, RHIBs leave a huge wake behind them, a sign of the great amount of power used to propel them.
More comfortable: Some luxury small RHIBs feature forward facing seats or benches, and their driver can steer by means of a steering wheel or a joystick. But most small RHIBs offer just basic amenities, and their driver sits on their side, or on the side of the motor, next to the tiller, or on a bench in front of it. All these locations are sub-optimal in ergonomic terms and as far as driving is concerned, since they demand from the driver to face sideways, or drive with their arm stretched backward. Food for thought – Does any other vehicle require from its driver to sit in any of these awkward postures?… In contrast, Wavewalk’s RHIB offers its driver to ride a comfortable saddle and face forward, as they would in a personal watercraft (PWC) a.k.a. jet-ski, an all terrain vehicle (ATV), or a snowmobile, which are vehicles designed for high performance in both tough conditions and at high speeds. Wavewalk’s RHIB is steered with a supersized joystick that’s intuitive to use and works perfectly when the driver sits or stands, without any adaptation required. This plug-in joystick and steering system require no installation, and it takes a few seconds to attach or detach it. The driver or the W-RHIB can start the motor in the most comfortable position, namely while facing backward, and once the motor is running, they can easily and swiftly turn around and face forward, as demonstrated in the video.