The simplest and most affordable primitive craft for crossing rivers and other water barriers is a raft. The raft can be connected from logs, boards, boards, reeds, reeds, branches of bushes, poles of empty barrels, cans, inflated automobile cameras and the like. The creation and construction of rafts does not require special experience and knowledge.
Design options for rafts for crossing rivers and other water barriers, determining the carrying capacity and construction features of a log raft.
By calculating the total weight of the cargo, carried property and equipment plus the weight of a person, it is possible to determine the number and parameters of logs for the construction of the raft. To do this, the total mass of the cargo must be divided by the load capacity of one log. To determine the lifting force of one log on the water, you need to measure its length and average diameter. The average diameter of the log is determined by measuring the diameters at both ends and dividing their sum in half (D + d) / 2.
The table for determining the carrying capacity and lifting force of one log for the construction of rafts.
The practical carrying capacity of logs of any tree species is determined by loading them in shallow water. In case the connected raft sinks, then you need to increase the number of logs.
Approximate loading capacity of other materials used for the construction of rafts.
Carrying capacity of 1 kg of dry straw or reeds about 3 kg.
Payload 1 kg wet straw approx. 1.5 kg.
Raft load capacity from empty containers, such as wooden or metal barrels, cans, paint cans or milk cans, plastic bottles and the like, 1 decimeter cubic (i.e. 1 liter capacity), per 1 kg of cargo weight.
Harvesting dry logs for the construction of rafts.
Mark with a notch a suitable dead wood (dried trees) in the amount necessary for the calculated raft capacity.
Trunk the trunk and fill it in the direction of the raft construction site.
Chop branches and branches. Select the desired (estimated) length of the log, chop off the excess.
Drag on the thin end of the log. If the weight of the log allows, it is easier to transfer it on the shoulders. Or with the help of ropes, tie one end of the rope to a non-sliding knot with a loop and put it on your shoulder or chest.
You can harvest logs upstream of the raft assembly site and then fuse them down the water.
The place for the construction of rafts should be flat and close to the water.
Design options for rafts for crossing rivers and other water barriers.
Features of the construction of rafts from logs, their launching.
It is better to build a raft ashore on a slipway, perpendicular to the channel. The guide rails should be raised horizontally on the supports from the river. For launching the finished raft or rafts, the stocks of the slipway must be knocked out so that the guide logs bend on one side towards the water and the raft moves along them into the river. It is possible to lay (at a distance between each other) several even, round logs parallel to the river channel and build a raft on them. When ready, roll the raft along the logs into the river. It will be much easier to launch the raft if you build it in shallow water.
Curved logs need to be humped up. Fix rotten logs with rotten side down. To use the raft on a river with a rapid flow, the thickest logs need to be attached along the edges of the rafts, for stability. On rivers with a weak current, the thickest logs need to be fixed in the middle of the rafts, it will be easier to pull the raft from the shallows and stones. It is better to trim the sides of the logs from the sides to reduce the gaps between them during assembly. It is better to make two lateral, external logs shorter than the rest and trim their ends at an angle to the raft, then it will be easier to control the raft in motion.
Based on the book “Survival beyond the threshold of civilization”.