Tag Archive: 5 hp outboard

5-hp outboard for fishing kayak

The world’s fastest kayak

What is the world’s fastest kayak?

The world’s fastest kayak is the Wavewalk S4, propelled by a 9.8 HP Tohatsu outboard motor. The S4 can go at a 17 mph speed (27 kmh) when propelled by a 9.8 HP motor, with only the driver on board.

What is the world’s speed record for kayaks?

The current kayak speed record is 17 mph (27 kmh). This speed record was achieved by Captain Larry Jarboe, in Key Largo, on January 17th, 2018, in a Wavewalk S4 outfitted with a 9.8 HP outboard motor.

What makes a kayak faster?

The factors that contribute to a kayak’s speed are its Size, Weight, Dimensions, and Propulsion.
Human Powered: In a paddling or pedaling mode on flat water, mono-hull kayaks with a high Length to Beam (L/B) ratio, namely very long and narrow kayaks, are generally faster than kayaks with a low L/B, which are more stable.
In choppy water, the kayak’s Stability and Balancing capabilities offered to its crew play a more important role.
Motorized: At high speeds, such as when the kayak is motorized by a powerful outboard motor, Stability and Balancing capabilities are the dominant speed factors, as the kayak moves in a planing mode and no longer in a displacement mode – The stabler the kayak, the easier and safer it is for its driver to drive it at high speed.
Additionally, kayaks that offer their driver to drive while seated closer to the motor are safer and easier to drive than kayaks that have the driver separated from the outboard motor by a longer distance.

Why is stability a key factor for speed?

Stability is defined as resistance to change. A kayak driven at high speed can flip over more easily than at a lower speed, and better lateral stability means that it can be driven at higher speeds with a lesser risk of overturning.

What is the most stable kayak?

The world’s most stable kayak is the Wavewalk S4. It is the only kayak that enables a 200 lbs full-size adult to stand on one side of the kayak with both feet, and turn around themselves as if they stood on the deck of a full-size boat. It is also the only kayak that can be driven at high speed in rough water, namely the most seaworthy kayak.
This unmatched stability results from the fact that the S4 features a patented twin hull. In this full fledged, true catamaran form, the boat’s volume is distributed along its left and right sides, where it is the most effective in offering maximum buoyancy and therefore best support for the shifting weight of both passengers and gear. This optimal performance is in contrast to other kayaks that feature conventional mono-hulls, where the hull’s volume is concentrated along the boat’s center line in a way that makes it the least effective in stability terms.

Why is balancing capability a key factor for kayak speed?

Being a small vessel, a kayak is inherently less stable than bigger boats, and therefore the ability of the kayak’s user(s) to balance themselves and their kayak effectively is key factor in the kayak’s overall stability.
Balancing capability is a key ergonomic factor for driving many types of small vehicles, both human powered and motorized.
It is particularly important in bicycles and motorcycles that offer no stability of their own, and therefore depend entirely on their users’ ability to balance them. Other vehicles that offer their users good balancing capabilities are All-Terrain Vehicles (ATV), snowmobiles, and Personal Watercraft (PWC).

What gives a kayak user better balancing capabilities?

A type of seat known as a Saddle is what all the above listed vehicles have in common. A saddle allows the user to balance themselves with their legs straddling the seat, in a manner similar to horse riding. The user straddling the saddle seat can easily and swiftly shift their weight from one leg to another, in a way that resembles balancing while running and jumping, namely more naturally, intuitively, and effectively than when seated in other positions, such as on a bench, swivel seat, chair, or in the notoriously uncomfortable and unstable L kayaking position.

What makes the Wavewalk S4 faster than other kayaks?

The Wavewalk S4 is the world’s fastest motorized kayak due to the fact that it is the world’s most stable kayak. This urivaled stability is made possible thanks to its twin-hull (catamaran hulls) and the ability of its crew to balance themselves effectively while riding a saddle seat, similarly to the way that Personal Watercraft (PWC) and other high performance vehicles (e.g. motorcycles, ATVs, snowmobiles) balance themselves and their vehicles.

The world’s fastest kayak in action (movies) –

The world speed record for vessels designated as kayaks:

Captain Larry Jarboe driving his S4 at 17 mph

 

High speed motor kayak in the ocean chop:

 

Speed comparison of S4 powered by a 5 HP vs 9.8 HP:

 

What are the advantages of a fast kayak?

The main advantages of a faster kayak is that it saves you time when you want to get somewhere, such as a productive fishery, and it makes it possible for you to access remote locations.
In addition, speed is enjoyable, and driving a fast kayak is fun.

Practically speaking, a fast and stable kayak that’s also highly seaworthy presents the advantages of a microskiff (micro skiff), in addition to being a car-top boat, and the ability to carry it to and from the beach, without depending on boat ramps.

 

5 HP vs. 9.8 HP outboard motor with the Wavewalk S4 kayak skiff

This is a movie that Captain Larry Jarboe of Wavewalk Adventures in Key Largo, FL shot while driving a Wavewalk S4 powered by a 5 HP 4-cycle Tohatsu outboard motor.
The second S4 featuring in this movie is Larry’s White Knight, the S4 workhorse that he uses daily for demos and guided fishing or diving tours, as well as a pleasure boat.
Larry outfitted the White Knight with a 9.8 HP 2-cycle Tohatsu outboard that propels it on flat water at 17 mph, which is currently the world speed record for kayaks* that Larry holds.
The guy seen in this video driving this fast boat (kayak…) is the guy who designs Wavewalk’s products, for better and for worse 😉

 

* Not every small vessel that’s compared to a kayak for marketing purpose is a US Coast Guard (USCG) designated kayak.
All Wavewalk’s patented catamaran kayaks and kayak-skiffs are officially designated as kayaks.

 

 

 

 

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

Updated April 10th, 2018

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 –

Power

  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).

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

Propeller Pitch

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.

 

KICKER MOTORS

 

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 OUTBOARDS

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:

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

No amount of words can overcome this reality.

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

 

Three boats, six hulls, one outboard motor, four divers, and one captain & guide

By Captain Larry Jarboe

Florida Fishing Kayaks

 

 

 

A Wavewalk 700 attached on each side of an S4 powered by a 5 HP outboard motor.

 

 


 

Larry offers guided fishing and diving trips in the Key Largo and the areas that surround it »

More fishing adventures with Capn’ Larry »

Wavewalk S4 on diving trip

By Captain Larry Jarboe

Florida Fishing Kayaks

 

Motorizing in the open sea and paddling in the no motor zone.

 

 

 

 


Larry also offers guided fishing and diving trips in the Key Largo and the areas that surround it »

 

More fishing adventures with Capn’ Larry »