Tag Archive: outboard gas engine

The smallest and greatest skiff

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.

 

 

 

Read more about the Wavewalk® Series 4 (S4) »

 

Developments in Motorized Kayaks

This article examines the latest developments in motor kayaks, and what these developments mean for anglers.

Origins of the motor kayak

As kayaks became increasingly popular among anglers, some of them started ‘rigging’ (outfitting) their kayaks with electric trolling motors. The need for doing so arose from the fact that paddling alone was insufficient in many ways – Monohull (common) sit-in and SOT kayaks are excessively wide, heavy and sluggish to their very inefficient design [¹], and paddling them to longer distances in not a possibility that’s offered to most people, especially in adverse conditions such as wind and current.

Typically, the motors used for this purpose were weak (30 lbs to 50 lbs thrust) trolling motors, powered by a 12 Volt lead-acid, deep-cycle marine battery. To this day, this is still a popular setup, and it stayed so thanks mainly to its low cost.

In this sense, kayak fishing, which started as a human powered sport, joined other forms of fishing from small craft, namely canoes, dinghies, etc.

More power and less weight: Lithium-Ion batteries

The advent of Lithium-Ion (Li-On) batteries [²] with their more effective power to weight ratio has added to the appeal of the electric motorized fishing kayak, and as these batteries became more affordable, they contributed to the spreading of motorized kayaks as yet another fishing platform in the market for portable vessels. However, besides their high price, these new batteries still present a problem to the user, and it is the fact that the amount of energy they store is still no match for the energy stored in gasoline, which powers internal combustion engines, namely outboard gas motors, or simply “outboards”.

As much as manufacturers of both kayaks and electric motors taut solutions based on the new Lithium-Ion batteries as the eco-friendly and quiet equivalent to motorboats, the fact of the matter is that they don’t compete well, at least when power and range of travel are concerned. Simply, the numbers are not there.

SOT Fishing kayaks with integrated electric motors – “Motor Kayaks”

In recent years, a growing number of kayak manufacturers has been offering fishing kayaks designed especially to work in a motorized mode, with an integrated electric power drive. Typically, the electric motor is inserted in a special compartment in the middle of the kayak, under the area where the user sits, and the propeller rotates under the hull. This design is not effective in more than one way, starting from the fact that it exposes the propeller to unwanted encounters with vegetation that can make it stall, and hard underwater objects and structures that can damage it. This makes such motor kayaks rather useless in shallow water and/or in water where vegetation abounds. To say that this defeats the purpose of kayak fishing may not be an overstatement. On top of this acute mobility problem, the location on the propeller under the kayak’s midsection makes it ineffective for steering, and forces the user to steer with a paddle and/or with a rudder system that adds unwanted complexity and clutter to a small vessel whose deck is already characterized by much clutter and too little workplace and comfort.
No wonder these big ticket and rather lame motor kayaks haven’t become popular.

A few words on the basic problems of matching motors and kayaks

Typically, common kayaks feature an elongated hull that’s pointy on both ends, and a cockpit that allows their user to sit in the middle of the deck. However, when small motors are concerned, having the user, namely the driver operate the motor from a close distance presents a major advantage in terms of safety, comfort, convenience and steering. For example, canoes, which feature hulls that are similar in shape to kayaks, are offered as paddling canoes with pointy front and rear ends, and square-end canoes where the transom is straight rather than pointy, and allows for mounting an outboard motor and for the driver to sit close to it.

Having the driver of a motorized kayak sit in the middle of the boat and operate a motor that’s several feet behind them doesn’t work well, and in case of an outboard (gas motor), it doesn’t work at all, despite attempts from a few kayak manufacturers to create demo videos that would give the impression that it does….

‘Hybrid’ fishing kayaks designed for motorizing

A couple of manufacturers of extra-wide hybrid fishing kayaks have tried to offer models designed especially for effective motorizing. The special thing about these models is that similarly to square end canoes, they feature a straight transom instead of a pointy rear end. The width of the transom varies, and in the models that feature a very wide transom, it makes the kayak fall outside the designation of kayak, per US Coast Guard regulations.
In any case, even hybrid kayaks (namely hybrid kayak / canoe) with an extremely wide transom don’t work as well as square end canoes, because unlike canoes, kayaks do not offer much in terms of free board, and as soon as the kayak’s rear is loaded with a motor and a driver, and it starts moving in the water with its front end pointing upward, its rear end sinks considerably and becomes too exposed to flooding for safe driving. And this happens even while driving on flat water, let alone in choppy water and waves.
Which is why these days the manufacturers of these kayaks are more low-key about them…

Pedaling anyone? (Just a side note)

In their eternal quest to differentiate themselves from the competition and stay relevant, kayak manufacturers end up offering new designs and solutions that are highly similar to each other. This happens not just in motorized kayaks, but in the market for pedal driven kayaks as well. And while pedal drives for kayaks are not within the scope of this article, it’s worthwhile to mention them since some vendors promote the fallacious notion that pedal kayaks could be an alternative to motorizing, although they certainly cannot, and they don’t even come close, at least when the real world and real people are concerned.
To simplify the ergonomics that apply to pedal drives and to human power in general, an average adult kayaker who is neither old nor impaired can produce around 75 Watts, namely 0.1 Horsepower (HP) at a sustained mode, and only for a few hours. In comparison, the smallest outboard gas engine available today, which is the Honda 2.3, can deliver over twenty times more power, and 6 HP outboard motors that some Wavewalk S4 owners use can deliver up to sixty times more power… and all outboards can run as long as there is fuel in their tank.
Are more words on this subject necessary?

Kayaks with jet drives

These specialty kayaks have been around for two decades, and they have not become popular although their performance in speed terms is impressive. The reason for this lack of market success is not just their price. It is the combination of the fact that they are still just SOT and sit-in kayaks, and this is not a good reference in terms of comfort and load capacity. Besides, jet drives don’t work that well in shallow water, where they can get clogged rather easily. In addition, unlike outboard motors that can be conveniently and inexpensively serviced by professionals at thousands of locations nationwide, proprietary jet drives are hard to fix, and fixing them requires support from the manufacturer, which is expensive and inconvenient.

“Kayak on steroids”

A heavy motorized board described by its manufacturer as a “kayak on steroids” and offered by them as a skiff for a solitary passenger is worth mentioning too, if only due to the fact that it relates to fishing kayaks, despite the fact that paddling it is harder than paddling most barge kayaks out there, namely the very big ones that are excessively wide and heavier than some dinghies. As this craft’s own owner’s manual states, it doesn’t work very well in choppy waters, and it shouldn’t be manned by more than one person. At 150 lbs without a motor, it is not a car-top boat, and it’s not a solution for anyone who doesn’t like to get wet while they engage in fishing or boating.
Enough said.

Fishing kayaks with outboard motors

What is the advantage of outboard gas motors?
As previously mentioned in this article, an outboard gas engine is the only type of propulsion that delivers sufficient power to allow for a kayak to go fast in all kinds of water, to run all day, and to travel for long distances. In other words, it’s powerful and reliable, and therefore safer and more fun.

YouTube features some videos of SOT kayaks outfitted with outboard gas motors. Some of these kayaks are outfitted with an outrigger, because unlike in YouTube, in the real world, SOT kayaks, including big ones, are not stable enough to be driven with outboard motors. Either way, the result is rather pathetic, and makes the viewer wonder about whether our species really deserves to be called Homo Sapiens, namely wise man… The drivers of such kayaks are noticeably uncomfortable, and in most cases wet as well. Not a pretty sight.

Practically speaking, Wavewalk kayaks are the only kayaks that offer full functionality and high performance when powered with outboard gas motors. This is why the company labeled its two bigger models skiff and portable boat. Indeed, they perform perfectly as such, and even better, be it in terms of stability, ease of use, comfort in driving, comfort to the passengers, dryness, load capacity, mobility, speed and seaworthiness.

 

The Wavewalk is a patented invention, and it can be described as a compacted catamaran that features the saddle-seat of a personal watercraft (PWC) also known as jet-ski. This unique combination creates the most stable hull while offering the driver and passengers to balance themselves intuitively and effortlessly, in the most effective way possible.
The result is a boat that punches way above its weight in terms of performance, to a point that it rivals much bigger boats.
And indeed, some anglers and other fishers use their S4 instead of much bigger boats that they used to have before.
For example, this crew of two shrimpers used an 18 ft skiff before they switched to the S4:

 

Motorizing options for Wavewalk kayaks are not limited to conventional outboard motors. In fact, it is possible to outfit the S4 with powerful surface-drive motors (a.k.a. mud motors), and by doing so, enhance their mobility and enable their users to go through very shallow water (“skinny water”), rocky streams, and water with abundant vegetation, such as lily pads, grass, and seaweeds.

And let us not forget paddling, because the ability to propel a motor kayak with paddles as an alternative or complementary mode of propulsion is very important, to a point where it may be critical in certain situations, such as launching and beaching in tough spots, going in very shallow water where a boat could get stranded, especially at low tide, going through weeds, and in case something else prevents the motor from working.


[¹] See articles about kayak design for speed: The Secrets of the SOT Kayak’s Underside , and Kayak Design for Speed

[²] See article Smarter electric motors and Lithium-Ion batteries – A winning combination for kayak fishing, by Gary Thorberg

Related articles

How much HP for my S4 skiff’s outboard motor?

Motorized Kayaks

Wavewalk 700 Test Ride 2017

By Rox Davis

 

Got my W700 and got to making some adjustments.
Kept the motor mount it came with for now, but will be making a new one soon.
It was a fun day at Rainbow Res in Ct. Motor ran like a top, I even caught some Bass.
Love how the W700 handled and felt going thru the choppy water.
And just like the W500 which is a very stable kayak, the W700 is more of a solid ride.
All in all I love it and can’t wait to finish some changes and two of us get out there fishing.

Thanks Wavewalk for another fine water craft

Life is good.

 

 


Read more about Rox Davis and her bass fishing adventures »

How much HP for my S4 skiff’s outboard motor?

Updated December 1st, 2017

The purpose of this article to answer a frequently asked question (FAQ) from prospecting clients, which is “What outboard motor should I choose for my S4 skiff?”

The answer is that the outboard motor and propeller you should choose for your S4 depend mainly on two factors, which are

  1. How much power you need: How fast you want to go, in what kind of water, and how many passengers you’ll have on board
  2. How important to you is the motor’s weight.

There is a trade-off between power and weight, namely that the more powerful the motor, the heavier it is, and the harder it is to carry it.

In any case, the motor should be a 20″ log shaft (L) model, and not a 15″ short shaft (S) model.

Recommended reading: How to measure an outboard motor’s propeller shaft length? »

Propeller Pitch

Another trade-off that you should know about is related to propellers: High pitch propellers are designed to deliver less torque (push force) and more speed, and they work best with lightweight boats, while low pitch propellers are designed to move bigger and heavier boats, but they should not be used with lightweight boats, since they can make the motor go 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”.

Propeller pitch information is available on outboard manufacturers’ websites.

Practically, this means that since the S4 is an extremely lightweight boat, you should outfit the outboard motor for your S4 with the highest pitch propeller available for it.

Diameter – Don’t try to use a propeller from a small outboard with a bigger outboard.

 

SMALL OUTBOARDS

 

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 OUTBOARDS

 

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.
We say get the 7 pitch, 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 speeds of up to 18 mph, and it can propel the boat at 13 mph with three passengers on board.
6 HP motors are the second most popular motors among S4 users.

Propeller pitch
For their 6 HP outboard used with lightweight boats (such as the S4), Tohatsu recommends their 9 pitch propeller.

 

BIG OUTBOARDS

 

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, they 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.

8 HP outboards

Outboard motors in this class weigh around 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.

9.9 HP outboards

We tested the S4 with 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 feel you must go at high speeds, and you’re capable of driving small boats safely at such speeds.

We recommend that inexperienced drivers avoid using high power motors. Instead, they should pick a motor within the 3.5 HP to 6 HP range.

 

MUD MOTORS

Mud 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.

6.5 HP mud motors

Mud motors are bulkier and heavier than regular outboard 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 OUTBOARDS

Electric outboard motors

Some electric trolling motors are described by their manufacturer as “outboard motors”, namely comparable in power to small outboard gas engines. If you consider such electric motors, we recommend remembering the laws of physics, and applying the formulae for Kilowatts to Horsepower conversion, which are:

  • 1 KW = 1.34 HP
  • 1 HP = 0.745 KW

No amount of words may overcome this reality.

Electric motors are discussed in the Electric Trolling Motor or Outboard Gas Engine section of this article »

 

 

 

 

Wavewalk S4 with a 6.5 HP mud motor – first test

By Chris Henderson

Fishing Kayaks of Gig Harbor

Today I was able to do my first test drive of the Wavewalk S4 with a mud motor!

As a duck hunter the potential for the S4 is incredible. Couple that with a mud motor and you can access places that others cannot go. I hunt tidal mud flats where traditional boat motors are difficult to use due to the changing tides (water depth) as well as the sand bars that constantly shift. The mud motor allows operation in very shallow water and lets me get over those sand bars. Other duck hunters hunt in flooded timber where the logs eat propellers for lunch and occasionally eat whole lower units. The mud motor is the only way to travel safely in those kind of swamps. That is why putting a mud motor on the S4 is like combining peanut butter and chocolate.
This was my very first run, so I have a lot to learn about operating this kind of motor.

There are a lot of different styles of mud motors out there and the cost can be very prohibitive. But I found a kit which is created by Mud-skipper called the Twister. Rather than a straight shaft it has a curved shaft. At first I was concerned that due to this the turning radius of the boat would be dramatically effected. As it turns out that fear was unwarranted. The two hulls actually keep you from turning too sharp which could cause you to overturn considering the nature of how the motor turns. The 6.5 hp was plenty of horse power and I cavitated way before I ran out of power.

Lots of experimenting to do to get it all dialed in but it was a great first test run.

 

 

 

 

 

 

 

 


 

More kayak rigging, fishing and bow duck hunting with Chris »