I usually keep my Wavewalk S4 on my dock so I can use it right there. But sometimes, we like to explore other areas. I don’t have a truck to transport it, so I decided to convert an old sailboat trailer into a Wavewalk S4 trailer.
All it took was some treated 2×6 and 2×4 boards, some U-bolts, and some ceramic deck screws. I started with the trailer for a [brand name] sailing catamaran that I don’t use. I’ve never trailered that boat. The first step was to attach two 2×6 boards each with a U-bolt on the front and the back. On top of those, I screwed five 2×6 cross-boards so they support the boat from underneath all the way from front to back. Then I added 2×4 boards on both of the outside edges to provide an outer groove for the S4 to sit inside. A set of rollers from the sailboat trailer act as guides to align the inner hull of the S4.
The result? A very light but stable platform to pull my Wavewalk S4. When we get to the boat ramp we just back it down the ramp and the S4 slides off the trailer with an easy push. You should have seen the faces of the big boat owners at the ramp when I launched my boat with one finger!
The key to trailering the boat is to make sure it is tied down securely in the front and the back so that it doesn’t slide forward or backwards. I also have two lines over the top of the boat to hold it down, but be careful not to over-tighten these and compress the hull. Also, remember to tilt the motor up if you have one so it doesn’t hit the ground as you trailer it.
Having a homemade trailer can extend the range of your Wavewalk adventures and save the hassle of loading it in or on top of your vehicle. All it takes is a used trailer and some treated boards!
This review of the Wavewalk S4 kayak skiff was written by the guy who designed it, as well as the W500 and W700.
Why this Wavewalk S4 review?
Typically, kayak and boat reviews are written by clients who mean what they say, but aren’t necessarily professional, or by people that the manufacturer paid to review their product. The latter reviews are not objective to begin with, and in many cases they are not even professional. Designers seldom publish reviews of the kayak or boat that they designed. Other reviews commonly found on the web are fake, and they were written by individuals who are affiliated with the manufacturer of the reviewed product (fake positive reviews) or with their competitors (fake negative reviews). Some fake reviews that appear on websites that offer people to publish kayak and boat reviews appear to have been written under an alias by the website owners, probably in order to make their website look more popular than it is in reality.
Wavewalk does not pay people to review its products, and it does not post anonymous reviews on websites that offer to do so to anyone who can come up with an alias and a few sentences. We think that such websites have a low credibility from the beginning, and their credibility has declined over the years, as people who read the reviews that these websites feature have become used to apply critical reading, and common sense.
We decided to publish our own review of the Wavewalk S4 after it’s been out there for nearly a year, which is enough time for us to see what it can do, and what our clients think of it (Read S4 clients’ reviews » ). In this review of the S4, we try to compare our initial plans for this boat to what it does in reality, and we also try to look into the future, as much as possible, and see what it could still do. Many Wavewalk clients are interested in the design of kayak and small boats, and we think that such people may have a particular interest in reading this review.
Why the Wavewalk S4?
It takes close to a hundred thousand dollars to produce a new product such as the S4 in terms of time and money invested in the design and manufacturing of a capital tooling (rotational mold) for it. Once the product is out there, it takes more time and money to test and promote it. This means that before a small company decides to invest in the development of such a product, it needs to make sure that it has a good reason to do so, and preferably more than one good reason.
Before we started defining the requirements from a future Wavewalk product, we looked at existing products in various markets, including our own W700 that we had launched back in August of 2015 –
From the moment we launched it, the W700 became an immediate, remarkable success, both as a tandem kayak for touring and fishing (and hunting, photography, etc..) and as an ultralight portable motorboat / microskiff. This success gave us the motivation and the funds to take the Wavewalk concept to the next level. Our clients loved to motorize their W700, but few were willing to give up paddling altogether, and this convinced us that paddling was important, so we decided that our next product, namely the S4, will be more of a high performance, fast and seaworthy motorboat with a bigger payload capacity, but it would still offer good paddling capabilities as a kayak and a canoe. Another thing that our clients love in their W700 was the ability to car-top it without a problem, and this meant that the next Wavewalk had to be a car-top boat too.
Before we started to design the S4, we looked at different products in a number of markets, and tried to identify unfulfilled needs as well as opportunities for our new product –
Jon boats – These popular small motorboats feature a generally flat bottom hull and a spacious open cockpit, and they usually offer sufficient stability for a crew of one person, on flat water. When the crew includes more than one person, or the water gets choppy, these boats tend to deliver insufficient stability, and generally speaking, they are not seaworthy, including bigger and therefore more stable models that are stable enough on flat water. Since Jon boats are typically made from aluminum, they are not lightweight enough to be car topped, at least not by one person. And last but not least, paddling a Jon boat is not an option, at least not over a meaningful distance, so these boats are excluded from traveling in very shallow (dubbed “skinny”) water, and in water where much vegetation is to be found – unless they are outfitted with a surface drive (a.k.a. “mud motor”), which is typically more heavy than a standard outboard motor, and takes more room in the cockpit. The next Wavewalk had to offer as much carrying capacity as a good size Jon boat, while being at least as stable, and considerably more seaworthy. This had to be achieved while keeping the new product from being overly wide, since wide boats don’t paddle well. Needless to say that the new boat couldn’t be nearly as heavy as a Jon boat, since it had to be car-topped by one person. We achieved all this with the S4, and more, including successfully outfitting an S4 with a surface drive, as demonstrated by Chris Henderson, from Washington state.
Microskiffs – Small skiffs (“microskiffs”) are generally similar to Jon boats, and they too are designed mainly for fishing on flat water. The main differences are in the material used to make skiffs (typically fiberglass), and typical additional deck features and structures. These differences reflect the fact that microskiffs are used primarily in saltwater, which is corrosive for aluminum, and the fact that people who fish out of microskiffs like to practice sight fishing. Microskiffs don’t paddle well, to say the least, and they are too heavy to be car-topped, including a product that’s essentially a rotationally molded motorized board for a single user who’s not particularly heavy, and who fishes in flat water only. The next Wavewalk had to feature a front deck, for casting, go as fast as a small microskiff, and be more seaworthy – All this while offering its users to launch anywhere, namely to transport it on top of a vehicle, and not by trailer. We did it.
Motorized kayaks – Since both the W500 and W700 had already surpassed all products in this category, we deemed motorized kayaks too lame to serve as a basis for formulating requirements for a next generation Wavewalk. This is true for all but one pretty exciting kayak-like product for one person that’s officially designated as a boat, and is propelled by a 7 HP jet drive. When we weighed the pros and cons of a proprietary jet drive and compared them to the advantages offered by outboard motors, it became clear to us that the latter were the way to go, due to their initial cost, ease of troubleshooting, low maintenance, and high quality as well as effective local service offered to our clients. As for speed, we decided that the next Wavewalk would have to be at least as fast as that exciting jet-drive kayak-like watercraft, and if people had a special need to drive their S4 in extremely shallow water, they could outfit their new Wavewalk with a surface drive (mud motor), which works better than a jet drive, since it doesn’t get clogged. The next Wavewalk had to be a car-top boat, and portable in terms of carrying it over rugged terrain, something that said jet drive kayak-style watercraft is not. The new Wavewalk also had to be seaworthy, and transport at least two full size adult passengers, which that jet driven kayak style boat cannot do. We achieved all that.
Personal Watercraft (PWC) – Such comparison may seem odd at first sight, but Wavewalks and PWC share one important feature, which is their longitudinal saddle seats that offer their users to balance themselves in the most intuitive and efficient way, and enhance their boats’ performance both in terms of stability and seaworthiness. In this sense, it was appropriate for us to think about PWC, and establish some requirements from the new product that would have nothing to do with fishing or paddling, but would go to what people like in PWC, namely speed, seaworthiness, and fun. We realized that in order for an S4 to reach speeds that are close to the speed of a small, basic PWC, the S4 would have to be outfitted not just with an extremely powerful outboard motor, but also with a proper steering and control system to go with it, be it a wheel or a bar, something that hasn’t been done, so far. Captain Larry Jarboe clocked 17 mph in an S4 powered by a 9.8 HP outboard motor, and the same boat was driven at full throttle offshore in choppy seas, with the drivers holding the throttle grip in one hand. In comparison, a typical PWC can go at 40-50 mph, and the faster ones can go at much higher speeds. Something to think about… On the other hand, an S4 is much less expensive than a PWC, including small ones designed for one person, and it is also more versatile.
Inflatable dinghies – These fast, stable and seaworthy boats are popular with yacht and big boat owners, who use them as boat tenders. But these small inflatable boats are uncomfortable for their driver and passengers, who find it hard to stay dry in them, and they don’t paddle well. As for standing in them, it is not easy either. Compared to them, the W500 and even the W700 were inferior in terms of load capacity and speed, but neither of these is a problem with the S4, with its carrying capacity of 650 lbs and the high speed in which it can go, even in choppy water. Simply, the S4 is as seaworthy as a good size inflatable dinghy, while being drier, more comfortable, and offering better paddling and standing capabilities. The S4’s polyethylene hulls are more durable and dependable than the soft hulls of inflatable boats, and clients who use an S4 as a boat tender report the highest degree of satisfaction, even when they tow the S4 behind the mother ship, which is the kind of performance that we weren’t sure it would achieve when we started designing it.
Keeping the kayak designation and paddling functionality – In order to make it easier for our dealers to sell the S4, and for our clients to register it, we wanted to keep its design within the requirements that would designate it as a kayak, and not as a boat, and that wasn’t hard to do. We also wanted to keep the S4 work as a paddle craft, which we achieved by making the sides of the cockpit slant, thus allowing the paddlers to move their paddles more closely, easily, and effectively alongside the kayak.
A motorboat’s look – On the other hand, we wanted to distance the S4 as much as possible from the image of a kayak, because in comparison to motorboats, kayaks are sluggish, uncomfortable, unstable, and wet. Therefore, we got rid of all deck rigging items that are typical to kayaks, namely eyelets, hooks, bungees, rubber carry handles, and even flush mounted rod holders. The S4 comes with two integrated (molded-in) carry handles in its front tip, and a molded-in carry handle on each side of its rear hull tips. These molded-in carry handles are stronger than kayak handles that are riveted or bolted to the deck, they are as comfortable, and they look better.
Keeping the S4 cost low – The rotational mold for the S4’s twin hull cost more that the mold for a typical full-size SOT kayak. We also had to mold the saddle for the S4, but luckily, we managed to design it in a way that allows us to use the same saddle as the one used in the W700. This saved us tens of thousands of dollars on a mold for an S4 saddle, and we were able to keep the S4 unit price within a reasonable range, considering its high performance in so many applications.
Building it tough – Carrying heavier loads while going at higher speeds meant that the S4 would have to be tougher than the W700, which is why we decided to incorporate two wooden brackets in every S4, standard, compared to just one similar structural element in the W700.
The motor mount challenge – The S4 is made from high density polyethylene, similarly to other kayaks as well as a motorized board offered as a one-person skiff. Polyethylene is a resilient material, which makes it highly resistant to impact, but this critical advantage comes at a cost, which is that polyethylene walls tend to be flexible relatively to similar structures made from more rigid materials, e.g. fiberglass and wood. We knew that a motor mount that would serve to attach to the S4 heavy and powerful motors that generate a lot of torque couldn’t be made from polyethylene only. If we wanted such mount not to flex, it should feature a totally rigid and very sturdy mounting plate, made from the right materials for the job. This is why we created the S4’s motor mount with a broad basis molded in polyethylene, and a mounting plate made from a wooden composite named Medium Density Overlay (MDO), which has served us successfully for years in the W500 and W700. The basis of the S4’s motor mount structure is firmly anchored on both its sides in the boat’s two hulls, and it is bolted both to the cockpit’s rear wall and to the saddle’s rear wooden bracket, whose top is inserted into the cockpit’s spray deflector (coaming). So far, this combination of polyethylene structures, wood composite board, and steel, has proved itself to work under difficult conditions, with powerful motors running at full throttle, and the boat going at high speed in ocean waves.
Conception, birth, and growth
A new boat often starts as ideas that the designer’s mind generates in reaction to external stimuli, such as impressions, challenges or compliments. The general idea and major challenge with the S4 was to create a boat like which the world has never seen before, and no one had thought would be possible. We knew the Wavewalk invention would guarantee that whichever design we choose for a Wavewalk boat that’s wider than the W700, it would automatically become the world’s most stable kayak, as well as the world’s most stable boat for its size. Within this framework, we still had a lot of things to think about, including –
The new front deck – The main challenge was to depart from the previous ‘catamaran’ look, and create a front that would still perform as a twin-hull (catamaran), but offer some protection from spray as the boat goes in waves at high speed. The totally redesigned bow had to feature a front deck that would serve as a casting platform, similarly to casting decks that skiffs feature. Since we knew that the S4 would serve crews of two and possibly three anglers, a deck extending in front of the cockpit would also serve to put more distance between crew members, and thus make the boat both more functional and more comfortable for them to fish from. This is to say that the S4’s new style of front deck is the result of both aesthetic and ergonomic, namely practical considerations. Developing these ideas and turning them into a computer aided design (CAD) file required months of hard work, plenty of problem solving, and innovative thinking.
Displacement hull vs. planing hull – Understanding this subject requires some knowledge in kayak and/or boat design. The problem we addressed was that paddle craft (canoes, kayaks, etc.) travel at very low speeds, and the most efficient hull form for such low power propulsion and low speeds is called a displacement hull. In contrast, motorboats travel at much higher speeds, and people who drive them like to travel in a planing mode. The most efficient type of hull form for a small motorboat is a type of hull called planing hull. The S4 was required to serve both as a paddle craft and a motorboat, and do well in both applications. We realized that unlike the W700, most people who use the S4 would choose to motorize it, so we designed its hulls in a way that would offer top performance with a powerful motor, and still paddle well enough, and this is basically what the S4 has achieved in reality – One person can paddle it effectively and easily without reaching high speed, but they can also drive it with an outboard motor that’s powerful enough to propel bigger and heavier boats, and go at speeds that are considered high even by small boat standards, and inconceivable in kayak terms. Being big for a kayak, the S4 paddles better with a tandem crew than it does in a solo mode. It paddles equally well in canoeing and kayaking modes. In sum, the W700 is a great kayak that you can effectively motorize, while the S4 is a great motorboat that you can effectively paddle. It’s a subtle difference that’s worth remembering if you’re not sure which of these two models is better for you.
Launching the product, and testing it – We launched the S4 in May of 2017, and since then, the S4 has kept growing in terms of proving what it’s capable of doing. We were pleased to see that a 214 lbs guy could easily stand with both feet in one of the S4 hulls, and turn around, without flipping the boat, and without even making it tilt by much. We were more pleased to see three adult paddlers standing in it and paddling without any problem. But we were astonished to see three full-size guys fish standing out of a motorized S4, with one of them landing a good size fish in the boat. Many thanks to Mike Silva for these amazing pictures! We loved watching the videos that showed the S4 driven through lily pads, propelled with a surface drive powered by a 6.5 HP motor. But driving an S4 powered by a 9.8 HP going at full throttle was a blast, and it was such a smooth drive that it certainly opened the door for testing it with more powerful motors, as a couple S4 owners already said they will do.
Multi-boat configuration – Another innovative and inspiring development was Captain Larry Jarboe’s S4x3 multi-boat, composed of a motorized S4 hip-towing (side towing) an S4 on each side, and thus allowing the driver to transport a much larger number of passengers, in full comfort, and with the stability of a large size pontoon boat. Captain Jarboe uses the S4x3 multi-boat for his guided diving tours in Key Largo.
Big boats, seaworthiness, maintenance, etc. – Interestingly, the S4 is already used, successfully, as an alternative to full-size skiffs. Its users prefer their S4s to the large size boats that they had previously used because of its easy launching, shallow draft, and better seaworthiness in choppy water. Indeed, we found that if you happen to get seasick in a boat going or anchored in the chop, riding the saddle of an S4 would instantly cure you, whether you’re driving it or just taking a ride in it as a passenger. The S4 is practically immune to other motorboats’ wakes, including big and fast boats traveling at a short distance from it, and this is not an exaggeration but an accurate description of a pleasant reality. And the S4 works as a paddle craft, so that it’s practically impossible to get stranded at low tide when you fish from it. Another reason to prefer the S4 over a full size boat is that it’s totally maintenance free, and if you’ve never owned a boat, it would probably be hard for you to appreciate the importance of this fact.
Spray shield – It turned out that when one person drives the S4, even at high speed, and even in the chop, the hulls and front deck deflect much of the spray that’s generated when they hit waves. However, when a passenger sits in front of the S4 driver, their weight lowers the bow, and it tends to generate more spray when it hits waves. And this is when a spray shield can still be useful.
A new type of watercraft – The S4 has already shown that it’s a new type of watercraft with a performance envelope that sets it apart from all boats of similar size. But it still has room to grow, in the sense of showing that it’s capable of more. We’ve already mentioned more exploits with mud motors, as well as bigger and more powerful outboard motors. We’d also like to show how a sculling (shell rowing) coach from Massachusetts uses his S4 as a coaching boat because he’s found that it generates a much smaller wake than other boats of similar size, and a small wake is the name of the game when coaching this sport is concerned. On the other side of the performance spectrum, we should find an opportunity to run the S4 in rough seas with inflatable flotation modules attached to its sides, RHIB style (RHIB stands for rigid hull inflatable boat). And on a completely different angle, we’re waiting for clients who use their S4 in whitewater, as a guide boat and a raft, to send us pictures too.
Extreme efficiency with a 1:6 weight to load ratio (payload ratio) – The S4 weighs a little less than 100 lbs without a motor, and it can carry a payload of over 650 lbs including a motor. This is a solid 1:6 weight to load ratio that shows how efficient the S4 design is.
We could have talked more about our S4, but with 3,700 words, this review is getting too long for a reasonable person to read – Thank you for making it this far 🙂
I finally got a chance to take the S4 out and test it on the water. It’s working beautifully with the Honda 2.3 engine. We actually have 3 people seat in it comfortably and both paddling and using the motor works quite well.
We launched the S4 at a rocky beach, and dragging the S4 over the sharp rocks caused some scratches on the bottom of the S4. This is a minor issue, and I’ve decided not to worry about it 🙂
Overall, I am very satisfied with the S4. Great Kayak and I can’t wait to show it off to my friends on the next fishing trip!
I was too busy with the S4. There aren’t any pics while the S4 is cruising in the water since all three of us were in the S4 and didn’t have anyone to take pictures from the shore. Here are some of the pics my friend took on the beach –
Skiff design, built, main advantages, and noteworthy shortcomings
Skiffs come in different sizes and configurations, and similarly to Jon boats, they are flat bottomed mono-hulls, a feature that reduces draft, which is advantageous for fishing in shallow water. But this design feature also makes skiffs less seaworthy compared to other boats of similar size. This is yet another example of specialization that enhances the product’s performance in one application while diminishing its performance in others. Skiffs’ limited seaworthiness is the reason for their being unpopular as boats for offshore fishing, and opinions about their performance in bays and estuaries are mixed. The skiff design’s limited seaworthiness is one of the reasons why owners of big boats and yachts don’t use small skiffs dubbed microskiff as tenders. Typically, skiffs’ hulls are molded from fiberglass, mainly because this material is more durable in saltwater than aluminum, which is the most common building material in Jon boats. However, fiberglass doesn’t perform well in terms of impact resistance, and it requires maintenance, while other polymer resins (plastics) such as Polyethylene don’t. Fiberglass is also heavier than Polyethylene, too heavy to make a small skiff that’s lightweight enough to be transported on top of a vehicle’s roof, namely a portable skiff. Skiffs are propelled by one or more outboard motors mounted at their stern.
Typical skiff features
Depending on a skiff’s size and level of outfitting, it may feature a center console, a casting platform at its front, and a tall structure at the stern, for a person to use for poling and/or for sighting fish for one or more anglers fishing from the deck. Skiff are sometimes outfitted with an electric trolling motor, typically mounted at their bow. The main advantages of a frontal casting platform are that it offers the angler a broader range of casting, be it with bait, lures, flies, or a fishing net, and it puts a bigger distance between them and other fishers working from the middle of the deck. The main advantage of a center console is that it improves the driver’s comfort and stability, relatively to driving from the stern, and it allows them to drive standing. Poling is both exhausting and rather ineffective as a mode of propulsion, and therefore increasingly unpopular among anglers who fish the flats and other shallow water. This leaves the poling platform to serve mainly as a watchtower, and possibly as an ornament. Electric trolling motors are quiet, and they can be controlled remotely, which is one of the reasons that more skiff owners use them these days.
Microskiff – a class of very small small skiffs
Microskiff is a term that refers to compact skiffs, namely of small size, and typically of reduced features as well. The smaller size saves money on gas and maintenance, but the need to transport microskiffs on a trailer still presents a challenge in terms of launching and beaching, as well as storage. At the lowest end of microskiffs both in terms of size and price, is a group of large size boards, some of which feature backward pointing extensions that provide extra support for the outboard motor’s weight, and some that don’t. These boards usually offer enough stability and load capacity for just one user (I.E. “solo” skiff), and they hardly offer any free board, which pretty much guarantees that this user will get soaked, whether they like it or not. As far as comfort is concerned, these large size boards marketed as microskiffs or “solo” skiffs seem to be designed with no concern for ergonomics whatsoever, to a point where watching a video featuring such a skiff might give the viewer an uneasy feeling. In terms of portability and transportation, their small size allows for an unusually strong person to transport one on a pickup truck bed, but car topping such a vessel is beyond reach for anyone who’s not a professional weight lifter. Most of these board type skiffs are molded from fiberglass or other cold-molded resins, which reduces their impact resistance, durability, and therefore reliability. The board skiff that’s made from Polyethylene weighs 150 lbs without the motor, which is still too heavy to rival the portability of most fishing kayaks and canoes, and let’s not forget that square-stern canoes can be outfitted with small outboard motors… Despite their small size, including a beam (width) that’s narrower than the beam of conventional skiffs, board skiffs do not paddle well, a factor that reduces their appeal to anglers who fish skinny water and water where aquatic vegetation abounds.
The Wavewalk S4 – the smallest and greatest skiff
In physical terms, the Wavewalk S4 is smaller and much lighter than any skiff, microskiff, and board skiff, and it its Polyethylene hull makes it more resistant to impact. It is the only skiff that anyone can car top without help from a second person. The S4 can carry up to three adult fishermen on board, which is comparable to the crew size of good size skiffs, and it enables these anglers to fish at the same time and standing up, which is something that only full fledged medium sized and bigger skiffs may offer. The S4 is a much seaworthy skiff that can be driven through ocean waves and other choppy waters without problems, both in a solo mode and with a second passenger on board. The patented combination of its twin-hull (catamaran) and saddle seat is extremely stable as well as easy for the users to balance, even more than a personal watercraft (PWC). In fact, driving an S4 in the ocean and in choppy water is pure fun. The S4 offers plenty of free board, which is good news for passengers who are looking to stay dry, and it is the only skiff that can serve as a tender for a big boat or a yacht. The S4 offers its passengers to use the entire internal space of its twin hulls for on board storage, and this makes its storage capacity rival with full fledged and good size skiffs. Like a full fledged skiff, the S4 can be easily outfitted with a front mounted electric trolling motor. And unlike any other skiff, including the smallest board-type microskiffs, or kayak skiffs, the S4 works really well as a paddle craft, namely kayak or canoe, to a point that some owners use it as a fishing kayak, without even motorizing it. Typically, the S4 is used with outboard motors in the 3.5 HP to 6 HP range, but it can be powered by bigger motors.
In sum, the S4 is a craft that’s so advanced in performance and versatility that it deserves a class of its own.
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: