With a boat on… a bicycle

Our industry produces various inflatable and folding boats for fishermen, hunters, and water tourists. However, they do not satisfy the demanding tastes of consumers in everything, so many hobbyists make watercraft themselves.

I also set out to create a transportable, quickly folding boat that would also be light, stable and fast. He called it “Strug”: folding, tourist and fishing, universal, rowing.

For six years, “Strug” was tested and then was protected by copyright certificate for invention No. 1096159 A.

I would like to introduce amateurs to the design of the boat, since many are interested in it and would probably be able to make something similar.

The Struga body is assembled from six identical plates cut from sheets of rigid duralumin grade D16AT 1 mm thick. One edge of each plate is straight, the other has rounded ends with a radius of 2200 mm.

Three Ø 9 mm holes were made in the outer side plates of the body. The two bottom ones are used to install spacers, and the top one is for the seat. The top drilling point was chosen as follows: vertically 65 mm below the top edge of the plate, and horizontally in such a place that the center of gravity of the rower and load was approximately in the middle of the boat.

Attached to the sides of the boat on both sides with M4 through bolts in one row with a pitch of 400-500 mm (washers were placed under both the nuts and the bolt heads) were wooden planks with a cross-section of 45X10 mm, cut from a straight-grained, knot-free pine board. The length of the external strips is 1300, internal – 2500 mm. The ends of the latter are thin – beveled: over a length of 400 mm, their thickness decreases evenly from 10 to 3 mm.

The body plates are connected to each other: straight edges are connected to straight ones, rounded edges are connected to rounded ones. The joints of the latter form three so-called keel seams: one central and two lateral. When unfolding the boat, they undergo elastic deformation. Therefore, joining strips of 70 mm wide conveyor belt with two layers of nylon cord are attached here (the remaining layers are removed). At the point where the seams meet, the tapes are cut – adjusted to each other and secured with overlays.

Duralumin overlays 1300 mm long are installed on straight seams, and on the edges, with a gap of 2 mm, overlays 155 mm long are installed. Their width is 22, and their thickness is 2.5 mm. The M4 bolts securing them are spaced at 45 mm intervals.

To avoid stress in the material of the hull plates during deformation, pads 1300 mm long in the middle and 75 mm along the edges were used in the keel seams.

The bolt holes are offset by at least the size of the nut, and the protruding ends of the bolts are sawed off. This is done so that when folding the boat, the fastening nuts do not rest against each other.

“Strug” is equipped with oarlocks – wooden rods Ø 20 mm, protruding above the sides by 50 mm. The rods are glued into the holes of wooden bosses, screwed with M6 bolts to the outer planks.

The hull of the boat is held in the unfolded state by two spacers – duralumin tubes Ø 28 mm with threaded spikes that pass through the sides and are secured with nuts.

The rower in the Struga sits in a canvas seat. The seat frame consists of. telescopic backrest, crossbar and two side spokes. The first is similar to a spacer, only its length can vary. The pipes here are duralumin, thin-walled, Ø 40 and 42 mm. They are drilled with Ø 9 mm holes at intervals of 535 mm for attaching the side spokes.

The cylindrical cross beam (Ø 35 mm) is made of wood, its ends are beveled to fit the profile of the bottom (to increase the contact area), on which it rests freely. Two holes are drilled in the beam with a center-to-center distance of 535 mm.

Side spokes – duralumin tubes Ø 20 and length 505 mm; At their ends, support elements with threads are inserted for connection with the telescopic back and cross beam.

The seat is made from a piece of tarpaulin 900X500 mm. Its dimensions are chosen in such a way that when the rower sits down, the seat does not reach the bottom by 20-30 mm. This landing is the most comfortable, the center of gravity is low, and the boat’s stability is good.

It takes 3-5 minutes to bring the Strug into transport position. The same amount of time is spent on unfolding.

The dimensions of the boat in this position are such that they can accommodate a folding Kama bicycle. Conversely, the Strug can be transported by bicycle. Its weight without seat, oars and struts is 18 kg.

V. GRYANIN, Kirzhach, Vladimir region