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«Gulfstream» boat project — a boat with an automobile engine

The project of the boat «Gulfstream» — a boat with an automobile engine

Choosing the next boat project for self-construction, the editors decided to give preference to a high-speed boat, which has a modern design, equipped with a powerful light automobile engine and adapted for Sunday rest and small trips of a crew of four people.

Abroad, such boats, called «daycruiser» or «weekender», are now very popular. The publication of such a project is also supported by the fact that our industry currently does not produce anything like this, although, judging by the editorial mail, both individual amateur shipbuilders and trade union collectives of a number of enterprises and cooperatives are interested in the project of a typical «daycruiser».

Regardless of who will undertake the implementation of the published project of the «Gulfstream» boat, it is necessary to take another critical look at their capabilities, to realistically assess the upcoming difficulties. Moreover, the limited volume of the magazine does not allow us to provide working drawings and a full description of the construction technology. The published projects can serve as a guideline, the outline of a technical idea and involve the creative participation of the builder in solving each individual node, part or technological process.

These words apply to this project to the greatest extent. It is recommended for implementation by an experienced shipbuilder who is able to independently solve a lot of technical issues related to the construction of the hull, installation of the power plant, electrical equipment, etc. It is better if the «Gulfstream» boat is not the first vessel for those who undertake to build it. Otherwise, it will be difficult to avoid unnecessary labor costs, mistakes and even disappointments.

It is also important to really realize that considerable money will be required not only for the construction of the boat, the purchase of materials and equipment, but also for its further operation, especially if a powerful gasoline engine is installed. It is with the search and installation of the engine that one of the greatest difficulties will be associated.

Basic data of the «Gulfstream» boat
Longest length, m 6,96
Maximum width, m 2,54
Cheekbone width, m 2,22
Side height, m 1,36
Keeling of the bottom on the transom, deg. 17° 30´
Passenger capacity, people. 4
Displacement, t 1,8
Engine power, hp 110-150
Speed, km/h:  
with full load 48-52
maximum with driver and passenger 53-58

General view of the «Gulfstream» boat

General view of the «Gulfstream» boat

The dimensions of the «Gulfstream» boat were determined, first of all, by the desire to accommodate a crew of four people with a minimum level of comfort. In addition, the accepted dimensions, with the appropriate choice of contours, guarantee the safety of swimming in waters where a wave of about 3 points (maximum wave height of 1.2 m) is a normal phenomenon.

The displacement of the «Gulfstream» boat, subject to strict weight discipline during construction, will be about 1800 kg. And this means that in order to bring it to the planing mode, a minimum engine power of about 90 hp will be required. Recall that in our country practically only one model of a boat gasoline engine of this power is produced — «M8CHSPU-100», but it does not enter the retail network. This is a converted automobile 8-cylinder «GAZ-53» engine; its rated power is 100 hp at 3000 rpm. In the boat version, the specific weight of the engine, equipped with an angular reverse gear and a two-circuit cooling system, is 3.75 kg/hp. It is installed on service and traveling boats and can be purchased only on occasion — from a decommissioned boat.

But even if such a case presented itself, do not rush, but try to purchase a decommissioned «GAZ-13» or «GAZ-14» engine with a nominal capacity of 195 and 220 hp, respectively. In a very small series, there are also boat versions of these engines, which are installed on certain models of towed water skiers. In this case, you can count on an effective long-term power of 110-115 hp (On boats, the engine runs at constant power, unlike a car where a gearbox is used and the mode of operation depends on the road; therefore, on boats, in order to preserve motor life, automobile engines are operated at a power not higher than 50-60% of the nominal.) A reserve of power may be required, for example, when entering the planing of a loaded boat. As a transmission to the propeller, you can use a standard reverse gearbox of the «M8CHSPU-100» engine or another type. Generally speaking, it would be better to prefer an angular rotary-folding column or even a water jet propulsion to a vulnerable inclined propeller shaft, but they will have to be designed and manufactured independently.

In short, it is possible to start building the «Gulfstream» boat only after all issues related to the choice of engine and transmission have been resolved.

Table of plaz ordinates

Lines frame no.
1 2 3 4 5 6 7 8 9 10 11 12 Tr.
  Half-width from DP, mm
A     305 310 315                
B     766 904 956 952 950 950          
In         978 1012 1016 1016          
G     813 970 1050 1087 1090 1090 1090 1090      
D 1285 1310 1328 1340 1347 1350 1350 1350 1350 1350 1350 1350 1350
E 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200
W 373 643 842 980 1073 1134 1164 1176 1176 1176 1176 1176 1176
Z 204 454 667 832 957 1046 1098 1120 1120 1120 1120 1120 1120
Side spray width the bump 20 20 20 20 20 20 20 20 20 20 20 20 20
Width of the zygomatic spray the bump 5 12 20 36 54 72 80 88 94 110 140 190 250
Redan I   48 224 353 457 490 518 532 532 502      
Redan width I   8 34 58 70 80 80 80 80 50      
Redan II 39 277 468 618 725 803 841 856 856 856 856 856 856
Width of redan II 3 36 52 60 68 78 80 80 80 80 80 80 80
  Heights from OL, mm
A     1500 1625 1693                
B     1455 1546 1630 1712 1720 1720          
In         1582 1582 1582 1582          
G     1340 1352 1357 1360 1360 1360 1360 1360      
D 594 885 1066 1167 1210 1230 1230 1230 1230 1230 1230 1230 1230
E 622 914 1093 1200 1245 1268 1268 1268 1268 1268 1268 1268 1268
W 966 894 832 787 750 726 715 705 705 705 705 705 705
Z 800 670 558 470 410 375 356 350 350 350 350 350 350
Keel 608 319 140 46 8 0              
Attention! In «Boats and yachts» mistakes were made in the table of plaz ordinates. This table is published with the necessary corrections.

Theoretical drawing of the «Gulfstream» boat

Theoretical drawing of the «Gulfstream» boat
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Theoretical drawing of the «Gulfstream» boat The sharp-cheeked contours of the hull are a monohedron with an angle of external keeling of the bottom on the transom of 17.5°. In combination with the stem cut along a smooth curve and the collapse of the sides in the nose, this allows you to maintain a maximum speed of up to 53-58 km/h on excitement up to half a meter. To partially compensate for the loss of hydrodynamic quality due to the increased keelness of the hull, two longitudinal redans and zygomatic mudguards are installed on the bottom on each side of the keel. In the stern, the zygomatic splashers turn into wide platforms, thanks to which the running trim is reduced and the boat's access to planing is facilitated. At speeds over 50 km/h, the proportion of air resistance becomes an important component of the total resistance of the vessel. Y «Gulfstream» boats a swift, «sleek» silhouette, characteristic of modern high-speed boats and characterized by a low coefficient of drag. It is also characterized by low windage, which affects the running qualities of boats in crosswinds. A distinctive feature of the silhouette of the boat is also a U-shaped mast-bracket, which serves as a support for setting up running and parking awnings, placing a top light, antenna, siren, etc.

The stern and bow platforms, the so-called «balconies», have become characteristic of modern boats. «Gulfstream» also has them. The bow platform is convenient for working with an anchor, lifting passengers onto the deck of a boat standing near the sandy shore. A small ladder is reinforced under the platform, which descends after the mortgage checks are removed. The aft platform is also convenient for boarding passengers, when mooring; a ladder made of stainless steel pipes is lowered from the platform to lift a person out of the water. A small bracket is also fixed here for installing an outboard motor in emergency situations. Under the slat of the platform there is a place for storing the stern anchor, ends, etc. A part of the steering device is mounted on its lower surface.

The completeness of the silhouette of the «Gulfstream» boat is given by three rails, which ensure the safety of passengers when passing along the deck. Two of them, made of stainless steel pipes, are mounted on the bow platform and on the roof of the cabin, and the third, wooden, is in the stern on the sides of the cockpit. The peculiar appearance of the boat is also given by a strongly inclined windshield with flat edges, wide and low windows in the side walls of the cabin, a glazed window that can open in hot weather. Otherwise, the general location and equipment are traditional for boats of such dimensions and purpose.

Diagram of the general location of the boat «Gulfstream»

Diagram of the general location of the boat «Gulfstream»
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The central and almost the entire bow of the vessel is occupied by a bright and spacious cabin measuring 3,6x1,9 m. The height of the podolok in DP — 1.5 m — allows the entire crew to comfortably sit at the table, and the cook, busy cooking, can stand at full height with the hatch cover shifted. The galley (gas stove and refrigerator «Morozko») is located on the left side. The galley lid reclines on the bracket and increases the plane of the table. Above the stove there are lockers for storing dishes, spices and food supplies. The dining table can be lowered to the level of sofas and then with the help of a tabletop it is possible to equip two sleeping places located across the boat. If necessary, two more people can be accommodated in the bow on the side sofas along the sides. Lockers for storing sleeping accessories and camping equipment are arranged in the bases of the sofas. In the forward part of the cabin on the sides there are shelves for storing personal belongings of the crew. On the starboard side there is a wardrobe, on the top cover of which you can install a radio or a portable TV. To ventilate the cabin, a hatch is made in the roof, through which, if necessary, mooring or towing ends can be secured to the bow ducks. The driver and passengers in the cockpit are protected from wind and splashes by a developed windscreen, and in the rain by a removable awning consisting of two parts. There are four seats in the cockpit; it is made deep enough, so it is quite safe to be in it, even with a strong pitching. In the aft part of the cockpit deck there are drainage (with non-return valves) scuppers, through which the trapped water is quickly removed by gravity, since the flooring is located above the waterline. By the way, the electrical wiring for safety runs along the upper edge of the transom.

The engine is closed by a wooden hood with noise insulation on the inner surface. The engine compartment must be equipped with an exhaust fan, which is switched on before each engine start, as well as ventilation of the compartment on the move using supply and exhaust ducts. Ventilation must also be provided in the compartments where the battery and fuel will be placed. These compartments should be separated from each other by non-combustible bulkheads. To ensure unsinkability, about 1 m of foam will need to be placed under the deck in the bow and stern. The hull of the boat can be sheathed with any waterproof plywood (preferably with a thickness of 6-8 mm on the bottom and 5-6 mm on the sides). All parts of the set are made of straight-layer air-dried pine, without knots and other defects. The nodes should be assembled on water-resistant adhesives with brass screws pressed in. After installing the skin, it is recommended to paint the set and the skin itself with hot drying oil, and to glue the outside of the body with fiberglass on an epoxy binder: the bottom in two layers, and the sides in one. The zygomatic splash guard and longitudinal redans should be installed after pasting the bottom with fiberglass.

For the manufacture of cabin doors, furniture, railing, slates of platforms, mahogany is most preferable, which must be impregnated with hot drying oil and varnished. The hull of the Gulfstream boat is best painted with epoxy paints in several layers (up to four) with subsequent polishing. This paint is least susceptible to fouling during operation.

It is recommended to install a collar made of black high-pressure polyethylene along the privalny beam — it has proven itself well for this purpose. Mooring and towing devices consist of two pairs of ducks (in the bow and in the stern) and an eye fixed on the stem. Along the side on the walls of the cabin, rims should be installed for fixing the fenders.

Structural sections on frames 3, 6 and 10
Structural sections on frames 3, 6 and 10
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1 — roof of the cabin, plywood δ=4-5; 2 — beams of the cabin 22x35, glued from rails; 3 — rack 22x45; 4 — half beams 22x40; 5 — toptimbers 22x90; 6 — shelf (sofa support) 22x40; 7 — flortimbers 22X90; 8 — rack 22x40; 9 — support rail 22x50 payola; 10 — keel 60x120; glue from rails; 11 — knits, plywood 6x180x380; 12 — payol, plywood δ=8-10; 13 — longitudinal redan 26x80; 14 — bottom lining, plywood δ=6-8; 15 — bottom stringer 20x60; 16 — sofa flooring, plywood δ=8; 17 — bryzgootboynik zygomatic; 18 — zygomatic stringer, glue from two slats 25x50; 19 — knits, plywood 6x180x320; 20 — side lining, plywood δ=5-6; 21 — side stringer 15x50; 22 — sofa back, plywood δ=4; 23 — inner timber, 25x60; 24 — collar, polyethylene 20x30; 25 — outer timber 20x50; 26 — knits, plywood 6x150x220; 27 — bulwark binding 30x35; 28 — porthole, plexiglass δ=8; 29 — manhole covers 8x30; 30 — knits, plywood; 31 — knits, plywood 120x260; 32 — shelf, plywood δ=6; 33 — flooring bow sofa, plywood δ=8; 34 — knits, plywood 6x160x200; 35 — knits, plywood 6x90x360; 36 — bar, 22x60; 37 — the support bar of the cockpit, 30x50; 38 — the support rail of the payola 22x60; 39 — knits, plywood 6x180x220; 40 — brackets for the footstock, rebound hook, rods; 41 — knits, plywood 6x140x220; 42 — mast bracket, plywood δ=3, pine slats.

In conclusion, we add that one of the Leningrad amateurs has already built a boat according to the drawings given. However, its architecture was somewhat changed during the construction process.

The two-year experience of operating the «Gulfstream» boat (it has a «GAZ-14» engine running on an angular column) fully confirmed the expected results.

Boat projects for self-construction

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