Tag Archive: polyethylene

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) »

 

Watertight riveting in kayaks and boats

Updated October 6, 2017

Pop rivets are widely used in the construction of boats, canoes, and kayaks.
Sealing rivets can be useful as a measure of extra precaution in case they come in contact with the water through which your kayak or boat goes.

How to better seal the rivets

Here are some tips for watertight riveting of kayaks and small boats made from Polyethylene –

  1. Polyethylene is the most widely used polymer resin (namely “plastic”) in kayaks, and it’s softer than aluminum and fiberglass used to produce other small boats. For this reason, it is recommended to use special aluminum rivets designed for riveting jobs in kayaks. These special rivets split in three, which increases their grip on the surface around the rivet. You can get these rivets in outfitters stores, and online.
  2. Drill holes of exactly the same diameter of the rivet that you use (3/16″), and preferably slightly smaller holes (5/32″).
  3. Apply a dub of Goop adhesive on the hole, and push the Goop into the hole. Goop is a powerful watertight adhesive used for plumbing and marine projects. The Goop you squeeze into the hole will coat its sides, and come out on the other side.
  4. Before you insert the rivet into the hole, coat its end with Goop. As you push the rivet into the hole, its tip will come out on the other side, and it will be coated with a thick layer of Goop. The sides of the rivet will be coated with Goop as well.
    gooping-the-rivet-01

    A rivet dipped in Goop watertight adhesive

    As you pull the rivet’s mandrel, the rivet will split in three and it will attach the two plastic walls while being coated with Goop. Excess Goop that will not come out on the other side or coat the sides of the hole, will remain on the outer surface and get squeezed by the rivet’s head. This way, the rivet’s parts that come in contact with the plastic will be coated with Goop, which will make them watertight.

  5. After you’re done riveting, coat the rivet’s head and the surface area around it with a generous amount of Goop. This will prevent water from touching the rivet, and in case of saltwater, it will prevent corrosion.

3M 4693 Scotch Grip TM H Plastic Adhesive – Good for Use in Polyethylene Kayaks?

‘Plastic’ kayaks is a term that refers in most cases to rotationally molded Polyethylene kayaks.
Polyethylene (HDPE, MDPE, LDPE and various commercial names) is by far the preferred resin in the kayak industry because of its superior performance when it comes to shock resistance, durability and overall reliability, but it is known to be quasi impossible to bond. This is because Polyethylene’s surface tension is low, which doesn’t allow for significant chemical reactions to occur, including bonding. The upside of this feature is that Polyethylene has superior resistance to strong solvents, acids, radiation etc., and indeed it is used for making fuel tanks and containers for active chemicals.

When an adhesive’s label says it bonds plastics it normally doesn’t mean Polyethylene.

3M is offering a an adhesive called 3M Scotch-Grip TM 4693 H Plastic Adhesive, and the company states it works for various plastic materials, Polyethylene included.

We tested this product and found that indeed it bonds with Polyethylene, and apparently a little better than other adhesives we know.
However, in our opinion the bonding is not sufficiently strong to allow use in structural repairs or for attaching accessories to a Polyethylene kayak, except maybe a fish finder, a decal etc., which are not required to support weight or resist even weak pulling forces at any time.

This adhesive could be used to seal rivet and bolt holes above waterline (E.G. with carry handles, rod holders, eyelets etc.). We would not recommend using it for sealing holes below waterline because we’re against drilling holes in kayak hulls below waterline in any case…

We would not recommend to use it for fixing cracks anywhere in the hull, and as far as filling gashes (such as those created by oysters) we don’t see the benefit of it, and we don’t see how the adhesive would stay in its place if it had to resist abrasive forces.

All in all, we found that common, general purpose adhesives such as the popular ‘Goop’ perform reasonably well too in such light duty tasks.

In sum, this adhesive cannot replace ‘hard’ methods such welding, riveting and bolting, but it can be useful in other ways.

How to Avoid and Repair Scratches in Your Kayak

Going with your kayak over oyster beds, shells, sharp rocks, broken glass, metal debris and even concrete ramps can get its hull scratched. In most cases such scratches are negligible, and you need not pay attention to them. However, if you want to avoid getting your kayak scratched you’d better watch out for signs of such potential hazards in the water – especially if you’re fishing or paddling in shallow water. Needless to mention is the fact that fishing and paddling from a higher position than ordinary kayaks offer you can help a lot in detecting potential problems in the water ahead of time, that is before hitting them. This is yet another advantage the W Kayak offers you, and W Kayak paddlers and fishermen indeed stand up in their boats from time to time to look at the water around them.

When it comes to repairing scratches in polyethylene kayaks the methods are similar and depend on how deep the scratch is.

For superficial scratches we don’t recommend any treatment, but if you insist on doing something you can just flame the scratch using a hand-held, propane blow torch. You should apply the flame over the scratch slowly and cautiously until it disappears or diminishes considerably, while being careful not to overheat the area so as not to cause a local deformation. In any case, flaming alters the color of the polyethylene to a darker hue.

hand torch and metal spoon for repairing scratches in kayaks

For deep scratches or ‘grooves’ it’s better to heat the end of a metal spoon and apply the hot tip gently and cautiously along the scratch, thus ‘welding’ the surface. Here too, you need to be careful not to overheat the area you’re working on since this would cause the polyethylene to deform. You’d need to protect your hand that’s holding the spoon with a thick glove since metal conducts heat and you might get your fingers burnt.

Keep the work area free of any flammable materials and make sure you’re not accidentally directing the flame at yourself or at other people. Don’t allow children or pets nearby.

If you’re not experienced in working with a propane blow torch you may want to reconsider such a project because it can be dangerous.

As for cracks in a polyethylene kayak, those are rare, and they must be properly fixed. Just flaming or welding won’t be enough to fix a crack, and you’d need to patch it – preferably with an internal patch that you’ll weld over the entire area. This is necessary since even if welded the hull in the cracked area will be weaker than in other places, and it could reopen while you’re paddling your kayak or fishing from it – with dire consequences. If the crack appears above waterline you can reinforce the patch with rivets, but we recommend not to use rivets when making repairs below waterline because we think that drilling holes in the hull below waterline is simple too risky in the long run.