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Motor hydrofoil boat Bottlenose dolphin. Hydrofoil boat design and construction

Leningrad water-motor tourists have long been acquainted with the motor boat ML, designed by the designer of the shipyard VTSPS M. L. Porzel for the motor Moscow. This boat served as a prototype for the development of the project offered to the attention of readers. The design of the hull has remained virtually unchanged, but the contours and architecture of the boat have been significantly redesigned.

The Bottlenose dolphin hydrofoil motorboat is designed for walking and short (one or two days) hikes along large rivers and ples, where there is a high probability of meeting with developed excitement. With an outboard motor with a capacity of 20-30 hp, the boat can be used as a water skier tow truck for practicing figure skating elements.

Basic data of a motor boat on wings
Longest length, m 4,42
Deck width, m 1,64
Width along the cheekbone on the transom, m 1,18
Side height amidships, m 0,68
Body weight, kg 130
Outboard motor, hp 14-30

Motor hydrofoil boat Bottlenose dolphin. Hydrofoil boat design and construction

The side profile of the boat is built in accordance with the so-called trochoid shape the shape of the wave profile, which gives the silhouette of the vessel a pleasant soft dynamism, emphasizing its high-speed and seaworthiness. The strongly inclined flat surfaces of the windshield gradually, along a concave curve, decrease in height to the stern, passing into a rigid high cockpit coaming.

The layout of the vessel, the elements of the equipment are no different from the projects repeatedly described in the collection and there is no need to dwell on them in detail. Note only that the seats on the boat are rigid, folding and can be removed into the bow under the deck; the cockpit is completely free and air mattresses or sleeping bags can be laid out here.

The steering wheel is proposed to be positioned on the deck behind the windshield on the port side so that the axis of the steering wheel is vertical. This arrangement facilitates access to the bow under-deck space, simplifies the design of the hull.

In my opinion, in conditions of minor unrest , the greatest efficiency of using a motor boat can be achieved by installing hydrofoils. The speed of almost any planing boat increases at the same time by 1.2-1.3 times or, accordingly, its carrying capacity increases without a significant drop in speed. In particular, there is a case of reaching the wings of a vessel weighing 800 kg under a 20-strong Vortex.

Theoretical drawing of a hydrofoil motor boat

Theoretical drawing of a hydrofoil motor boat
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Table of plaz ordinates

Half-latitude Heights from OL
KVL 1 vl 2 vl 3 vl board cheekbone buttocks keel cheekbone board deck
in DP
1 195 357 350 100 557 330 415 710 745
2 145 385 490 565 645 395 222 470 135 315 700 780
3 405 585 645 697 730 555 90 210 10 240 690 795
4 542 660 705 745 760 625 65 135 0 195 680 800
5 600 685 720 760 770 645 52 120 0 175 670 800
6 615 670 705 730 740 635 51 120 0 162 660 795
7 600 650 685 710 715 614 50 120 0 155 652 760
8(conl.) 580 625 685 690 590 49 120 0 150 645 735

Constructive longitudinal section and plan of a hydrofoil motor boat

Constructive longitudinal section and plan
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1 stem, pine, lamin., 50x60; 2 toptimbers, 20x50; 3 beams, 20x50; 4 deck stringer, 15x30; 5 beam ladder, aviafanera, 4x80x80; 6 filler, δ=20; 7 knitsa zygomatic, aviafanera, 4x80x80; 8 flortimbers, 20x50; 9 knitsa flora, aviafanera, δ=4; 10, 12, 13 rack, pad, stainless steel. steel, 2x30; 11 windscreen, org. glass, δ=5-8; 14 privalny beam, 20x30; 15 side stringer, 15x30; 16 piol support, 20x20; 17 flor, aviafanera δ=4; 18 keel; 30x50; 19 karlengs, 20x30; 20 glass frame, stainless steel. steel, δ=2; 21 demi - sims, δ=20; 22 velvet, pine 20x25 or ash 15x20; 23 lining, ash, 10x150; 24 stitching, aviafanera, laminated plastic, δ=2,5-3; 25 pillow, pine; 26 zygomatic rebound bar, 30x30; 27 zygomatic bar, 30x40; 28 longitudinal redan, oak, 30x60; 29 bottom stringer, 15x30; 30 glass fence, org. glass, δ=5-8; 31 breshtuk, pine, oak, δ=20; 32 transom trim, aviafanera, δ=6-8; 33 transom filler, δ=20; 34 transom interior trim, aviafanera, δ=4-6; 35 knitsa, oak, laminar., δ=20; 36 rack, oak, 25x100; 37 bulkhead skin, aviafanera, δ=6-8; 38 beams, pine, ash, δ=20; 39 support of stitching, 20x15; 40 midway, 15x50; 41 pillows, δ=20; 42 pillow under glass, 20x30; 43 side trim, aviafanera, δ=4-5; 44 covering of the bottom and deck, aviafanera, δ=5-6.

Cross sections on frames
Cross sections on frames
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Designations see on the longitudinal structural section.

The Bottlenose Dolphin's wing device consists of a forward V-shaped wing crossing the surface of the water and a aft flat low-loaded wing. The nose wing is attached to the body with curved bolts, under which washers are placed so high that the handle head is directed downward. If the wing is made of a light alloy, the thickness of the profile should be increased to 0.1 of the wing width. In any case, it is useful to put a bracket resting on the keel, under which the required height of the lining is selected in place. The aft wing is attached to a parallelogram on which the motor is mounted. The design allows you to raise and lower the motor and wing as needed. The springs are selected in such a way as to balance the weight of the motor with the wing, and then the system is held in the lowered state only by the screw stop.

Nose wing design

Nose wing construction
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1 wing, blank 15x220; 2 side rack, 10x80; 3 middle rack; 10x100; 4 wooden linings.

Aft wing design

Aft wing design
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1 wing, 10x130; 2 rack 10x100; 3 engine board; 4 screw M4x60; 8 pcs.; 5 bracket lever (square with a cut shelf); 6 spring; 7 bolt M10x20; 8 plate δ=3; 9 sleeve Ø 40x5; 10 tube Ø 20x5, L=30; 11 stop, weld from a bar Ø 10 mm; 12 bolt M10x30; 13 washer 10; 14 washer 14; 15 nut M10; 16 spring earring, δ=2; 17 bushing Ø 14x1.5, L=13.5, brass.

Only the simplest option of attaching the wings to the body is given here. A more successful, but also more complex system is described by A. S. Chugunov in the collection No. 26 (1970). The angles of installation of the wings are selected by successive approximation, but for the first exit, the nose wing must be installed with an angle of attack to the horizon minus 1-2, the stern +1.

Fuel tanks (we recommend using standard tanks for the Neptune engines) are installed behind the aft waterproof bulkhead, then in case of accidental splashing of the mixture, gasoline and oil do not get into the cockpit. It should be borne in mind that the boat will go planing faster with a more forward alignment, and after overcoming the resistance hump, the load can be shifted to the stern this will have little effect on speed.

A few words should be said about the contours and propellers. The Bottlenose Dolphin is a typical vessel with a deep V, but to improve the strength and hydrodynamic qualities of the hull, the bottom branches of the frames are given a significant bulge. At low speeds, the boat behaves like an ordinary keeled boat: blows on the strongly keeled bottom at the cheekbones are not great, but at full speed with a small load, the boat goes on an almost flat, strongly elongated section of the bottom with optimal angles of attack and is not sensitive to changes in alignment.

In the first approximation, you can pick up a screw using the recommendations of the given table (the motor Vortex-M):

Load Screw pitch, mm Diameter, mm
On the wings
2 people. 380 240
4 people. 300 240
Without wings
2 people. 280 240
4 people. 220 240
1 person. + 1 water skier 240 240

Three-bladed propellers with a disc ratio equal to 0.55 are recommended.

In conclusion, we note that the stem should be glued together from rails 6-8 mm thick, and after processing it should be docked with the keel at a length of at least 300 mm. Fasteners made of non-ferrous metals can be replaced with ordinary steel, but oil paint should be poured into the holes for screws and bolts. VIAM-B3 glue can be replaced with epoxy adhesives or K-17 glue, sometimes called synthetic carpentry, for which oxalic acid is used as a hardener.

Housing motor boats are recommended to be pasted with fiberglass and painted with epoxy enamels. In the absence of such enamels, pentaphthalic enamels or oil paints are used, but the case will have to be sanded beforehand.

VIAM-B3 glue can also be used to cover the bare body, but then 10-15% alcohol and 3-4% acetone are added to it. This composition penetrates well between the fibers of wood and reliably preserves it. During polymerization, the adhesive film is stretched and the surface is smooth and shiny. Over time, the coating acquires a dark cherry color.

Boat projects for self-construction

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