Method for assembling propeller tower and short engine room of hovercraft

Abstract

The invention relates to the technical field of hovercraft assembly, and discloses a method for assembling a propeller tower and a short engine room of a hovercraft, which is characterized in that a detection line reference system of a chassis frame and a height marker post is arranged at a ground prefabrication stage, so that the positioning adjustment of the propeller tower and the short engine room is completely completed at a low-altitude site; the operation risk that a scaffold is repeatedly erected and disassembled during high-altitude hoisting of a slipway in a traditional technology is avoided, a three-dimensional space positioning network is constructed by combining the plane datum of the chassis frame and the vertical datum of the height marker post, the precision error in the combining process is reduced, high-altitude closing operation of a traditional slipway stage is moved forwards to the ground site to be completed, and the working efficiency is improved. And the short engine room-paddle tower module only needs to be hoisted and positioned once when the ship body is finally carried, so that the processing period of a slipway is shortened, and the production cost of the hovercraft is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hovercraft assembly, and particularly to an assembly method for a paddle tower and a short engine room of a hovercraft. Background Art

[0002] In the field of hovercraft construction, the paddle tower section and the short engine room section, as the core load-bearing structures of the propulsion system base and the main engine equipment, their manufacturing precision and overall assembly quality directly determine the operating efficiency of the propulsion system and the performance indicators of the entire ship. These two special sections are usually prefabricated independently using special jigs, and finally need to be accurately joined with the main hull.

[0003] The existing process adopts an operation mode of sectional prefabrication - overall assembly on the shipbuilding berth, that is, after the paddle tower and the short engine room are independently fabricated on special jigs respectively, they need to wait until the hull enters the shipbuilding berth for hoisting and positioning. Since the design and installation position of this composite structure is in the superstructure deck area, there are significant technical bottlenecks such as difficulties in building the high-altitude operation platform and obstruction of the spatial positioning reference transmission. Specifically, the high-altitude suspension operation requires repeated erection and dismantling of multiple scaffolding systems, resulting in an extended auxiliary construction period and operation risks; multiple rounds of precision adjustment are required for the overall assembly of the sections, and it is difficult to control the welding deformation, with a high rework rate. These process defects not only cause the construction period to be extended by multiple working days, but also result in a low qualification rate of key indicators such as the flatness of the propulsion system base plane and the axial concentricity, seriously affecting the assembly precision and operation stability of the hovercraft power system. Although the industry has tried to optimize by improving the welding sequence, adding temporary supports, etc., it has not fundamentally solved the systematic process defects of the high-altitude overall assembly operation. Summary of the Invention

[0004] The purpose of the present invention is to provide an assembly method for a paddle tower and a short engine room of a hovercraft, which moves the high-altitude joining operation in the traditional shipbuilding berth stage to the ground site to complete, so that the short engine room - paddle tower module only needs to be hoisted and positioned once during the final hull installation, shortening the shipbuilding berth processing cycle and further reducing the production cost of the hovercraft.

[0005] To achieve the above purpose, the present invention provides an assembly method for a paddle tower and a short engine room of a hovercraft, including the following steps: Mark the reference lines on the paddle tower and the short engine room; Mark the detection lines on the chassis frame and the height benchmark respectively, and set the chassis frame and the height benchmark on the site; Hoist and fix the paddle tower on the chassis frame, determine the position of the paddle tower on the chassis frame according to the detection lines, and install strengthening tooling around the paddle tower; Erect the height benchmark on one side of the paddle tower, and open a process hole at the transverse wall of the closed frame at the front end of the paddle tower; Lift and install the short nacelle at the top of the pylon, determine the position of the short nacelle on the pylon according to the detection line, and set adjustable fixing parts to fixedly connect the short nacelle and the pylon; Determine the allowance at the upper opening of the pylon, draw the allowance line and cut the pylon according to the allowance line; Weld the connection between the pylon and the short nacelle to complete the assembly of the pylon and the short nacelle.

[0006] Compared with the prior art, the assembly method of the pylon and the short nacelle of an air-cushion vehicle in an embodiment of the present invention has the beneficial effects that: in this application, precise positioning of the pylon and the short nacelle is carried out by setting a chassis frame and height benchmarks, so that the positioning is accurate after the pylon and the short nacelle are lifted and installed, and then welding and assembly of the short nacelle and the pylon are carried out, so that the pre-assembly of the short nacelle and the welding is completed before the construction of the ship's platform; in this application, a detection line reference system of the chassis frame and height benchmarks is set in the ground prefabrication stage, so that the positioning and adjustment of the pylon and the short nacelle are completely completed in a low-altitude site, avoiding the operation risk of repeated erection and dismantling of scaffolding during high-altitude lifting on the ship's platform in the traditional process. Combining the plane reference of the chassis frame and the vertical reference of the height benchmarks to construct a three-dimensional space positioning network reduces the precision error in the combination process, and moves the high-altitude closing operation in the traditional ship's platform stage forward to the ground site to complete, so that the short nacelle-pylon module only needs single lifting and positioning during the final hull hoisting, shortening the ship's platform processing cycle and further reducing the production cost of the air-cushion vehicle.

[0007] In the assembly method of the pylon and the short nacelle of an air-cushion vehicle in an embodiment of the present invention, the detection line of the chassis frame includes the center line of the chassis frame, the rib detection line and the end face detection line for corresponding to the flange end face at the front end of the short nacelle, and the detection lines on the height benchmark include the water line, the horizontal fold line of the pylon outer plate and the propeller axis.

[0008] In the assembly method of the pylon and the short nacelle of an air-cushion vehicle in an embodiment of the present invention, when the chassis frame is set on the site, it includes the following steps: spot-weld the chassis frame to the floor jack on the site, and a steel-aluminum composite material is arranged at the top of the chassis frame to carry the pylon.

[0009] In the assembly method of the pylon and the short nacelle of an air-cushion vehicle in an embodiment of the present invention, when the pylon is fixed on the chassis frame, it includes the following steps: determine the levelness of the four corners of the pylon through the horizontal base surface, and then spot-weld the bottom of the pylon to the top of the steel-aluminum composite material, and one end of the bottom of the pylon close to the top of the steel-aluminum composite material is marked as the allowance area.

[0010] In the assembly method of the pylon and the short nacelle of an air-cushion vehicle in an embodiment of the present invention, the strengthening tooling includes first diagonal braces arranged on both sides of the pylon.

[0011] The assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention, wherein the adjustable fixing member includes a turnbuckle bolt with both ends respectively fixed to the paddle tower and the short engine room.

[0012] The assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention. Before hoisting the short engine room, draw the closing assembly line of the paddle tower on the bottom plate of the short engine room to align with the paddle tower during hoisting. After hoisting the short engine room, install a wire-pulling frame in the short engine room, and pull out the wires aligning with the propeller axis and the main engine axis on the wire-pulling frame by aligning the center line of the paddle tower. The wires are aligned with the horizontal base plane to adjust the levelness of the short engine room.

[0013] The assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention. When determining the allowance at the upper opening of the paddle tower, it includes the following steps: Determine the allowance at the upper opening of the paddle tower by comparing the height difference between the water line of the short engine room and the water line on the height benchmark with the closing assembly line on the bottom plate of the short engine room.

[0014] The assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention. After the levelness adjustment, recheck the height of the propulsion reducer base panel in the short engine room, then use the rudder mold to recheck the rudder installation height in the short engine room, and then use the plumb bob method to recheck the perpendicularity of the flange end face at the front end of the short engine room.

[0015] The assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention. Before welding the paddle tower and the short engine room, set up a horizontal support in the short engine room, set up second diagonal braces on both sides of the ground outside the short engine room, and set up a vertical support at the center line of the bottom of the short engine room.

[0016] The additional aspects and advantages of the present invention will be partly given in the following description, partly become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 2 is a schematic diagram of the chassis frame of the assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 3 is a combined schematic diagram of the paddle tower and the chassis frame of the assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 4 is a schematic diagram of the first diagonal brace of the assembling method of the paddle tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 5Schematic diagram of the adjustable fixing part of the assembly method of the propeller tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 6 Schematic diagram of strengthening before welding in the assembly method of the propeller tower and the short engine room of the hovercraft according to the embodiment of the present invention; Figure 7 Flow schematic diagram of the assembly method of the propeller tower and the short engine room of the hovercraft according to the embodiment of the present invention In the figure, 1 is the propeller tower; 11 is the margin area; 2 is the short engine room; 3 is the chassis frame; 31 is the steel-aluminum composite material; 4 is the strengthening tooling; 5 is the adjustable fixing part; 71 is the horizontal support; 72 is the second diagonal brace; 73 is the vertical support. Detailed implementation manners

[0018] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0020] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or the sequence relationship of the indicated technical features.

[0021] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0022] As Figure 1 and Figure 7 shown, an assembly method of a propeller tower and a short engine room of a hovercraft according to a preferred embodiment of the present invention includes the following steps: S1: Mark the reference lines on the propeller tower 1 and the short engine room 2; S2: Mark the detection lines on the chassis frame 3 and the height reference pole respectively, and set the chassis frame 3 and the height reference pole on the site; S3: Lift and fix the nacelle tower 1 on the chassis frame 3, determine the position of the nacelle tower 1 on the chassis frame 3 according to the detection lines, and install the strengthening tooling 4 around the nacelle tower 1; S4: Set up the height reference pole on one side of the nacelle tower 1, and open a process hole at the transverse wall of the closed frame at the front end of the nacelle tower 1; S5: Lift and install the short nacelle 2 on the top of the nacelle tower 1, determine the position of the short nacelle 2 on the nacelle tower 1 according to the detection lines, and set up the adjustable fixing part 5 to fixedly connect the short nacelle 2 and the nacelle tower 1; S6: Determine the allowance at the upper opening of the nacelle tower 1, draw the allowance line and cut the nacelle tower according to the allowance line; S7: Weld the connection between the nacelle tower 1 and the short nacelle 2 to complete the assembly of the nacelle tower 1 and the short nacelle 2.

[0023] In this application, by setting the chassis frame 3 and the height reference pole for the precise positioning of the nacelle tower 1 and the short nacelle 2, the positioning of the nacelle tower 1 and the short nacelle 2 is accurate after hoisting, and then the welding and assembly of the short nacelle 2 and the nacelle tower 1 are carried out, so that the pre-assembly of the short nacelle 2 and the welding are completed before building the ship's platform; in this application, by setting the detection line reference system of the chassis frame 3 and the height reference pole in the ground prefabrication stage, the positioning and adjustment of the nacelle tower 1 and the short nacelle 2 are completely completed in the low-altitude site, avoiding the operation risk of repeatedly erecting and dismantling the scaffolding during the high-altitude hoisting on the ship's platform in the traditional process. Combining the plane reference of the chassis frame 3 and the vertical reference of the height reference pole to construct a three-dimensional space positioning network reduces the precision error in the combination process, and moves the high-altitude closing operation in the traditional ship's platform stage forward to the ground site to complete, so that the short nacelle 2-nacelle tower 1 module only needs to be hoisted and positioned once during the final hull installation, shortening the ship's platform processing cycle and further reducing the production cost of the hovercraft.

[0024] In some embodiments of the implementation of the present invention, when preparing the site, the general assembly site should be kept clean, should not stack easily polluting substances, and is not suitable for mixed construction with steel structures; humidity sensors and wind speed sensors are set in the site, so that the relative humidity of the air in the site is less than 80%, and the wind speed should be less than 0.5 m / s. If the relative humidity of the air is greater than 90%, welding should be stopped. The chassis frame 3 is made of steel structure.

[0025] In some embodiments of the implementation of the present invention, the detection lines of the chassis frame 3 include the center line of the chassis frame 3, the rib detection line and the end face detection line for corresponding to the flange end face at the front end of the short nacelle 2, which are used for the positioning of the nacelle tower 1 and the short nacelle 2 in the horizontal direction. The detection lines on the height reference pole include the water line, the horizontal folding angle line of the outer plate of the nacelle tower 1 and the propeller axis, which are used for the positioning of the nacelle tower 1 and the short nacelle 2 in the vertical direction.

[0026] Such as Figure 2 AndFigure 3 As shown in the figure, in some embodiments of the present invention, in S2: when the chassis frame 3 is set on the site, the following steps are included: the chassis frame 3 is spot-welded and fixed to the floor jack on the site to ensure that the chassis frame 3 is firmly fixed during the assembly process, and the chassis frame 3 can also ensure the levelness with the ground to prevent affecting the accurate positioning of the blade tower 1 and the short nacelle 2; a steel-aluminum composite material 31 is arranged at the top of the chassis frame 3 to carry the blade tower 1.

[0027] In some embodiments of the present invention, in S3: when the blade tower 1 is fixed to the chassis frame 3, the following steps are included: determining the levelness of the four corners of the blade tower 1 through a horizontal base surface, and this process is adjusted by setting turnbuckles at the connection between the blade tower 1 and the chassis frame 3; specifically, the corner of the blade tower 1 is aligned with the horizontal fold line of the height benchmark. Then, the bottom of the blade tower 1 is spot-welded and fixed to the top of the steel-aluminum composite material 31; specifically, the blade tower 1 includes an outer side plate, and one end of the outer side plate close to the top of the steel-aluminum composite material 31 is marked as a surplus area 11, and the surplus area 11 is used for cutting after the blade tower 1 and the short nacelle 2 are welded to release the fixation of the blade tower 1 to the chassis frame 3.

[0028] As Figure 4 shown in the figure, in some embodiments of the present invention, the strengthening tooling 4 includes first diagonal braces arranged on both sides of the blade tower 1. There are multiple first diagonal braces on both sides of the blade tower 1, and the multiple first diagonal braces are evenly arranged along the length direction of the blade tower 1 to keep the support for the blade tower 1 firm.

[0029] As Figure 5 shown in the figure, in some embodiments of the present invention, the adjustable fixing part 5 includes turnbuckles with both ends respectively fixed to the blade tower 1 and the short nacelle 2. Specifically, a protrusion is arranged at the connection between the blade tower 1 and the short nacelle 2 for connecting the turnbuckle. The turnbuckle can adjust the distance between its own two ends through the sliding of the internal components, achieving the effect of adjusting the position between the blade tower 1 and the short nacelle 2. The adjustment by the turnbuckle is convenient to use and has sufficient strength.

[0030] In some embodiments of the present invention, in S5: before hoisting the short nacelle 2, a mating assembly line with the blade tower 1 is marked on the bottom plate of the short nacelle 2 to align with the blade tower 1 during hoisting, and is used for cutting the surplus at the mating part before welding. After hoisting the short nacelle 2, install a guy wire support in the short nacelle 2 at S5. On the guy wire support, pull out wires aligning with the centerline of the propeller tower 1 to align with the axis of the propeller and the axis of the main engine. The wires are aligned with the horizontal base surface to adjust the levelness of the short nacelle 2. Specifically, the wires extend to the axis of the propeller and the axis of the main engine at the height benchmark. By detecting the levelness of the wires, the levelness of the end integration is detected. The horizontal line represented by the laser emitted by the laser is used. If the wires are not parallel or collinear with the laser, the levelness is insufficient, and the relative position of the short nacelle 2 and the propeller tower 1 needs to be further adjusted by a turnbuckle.

[0031] In some embodiments of the present invention, at S6: when determining the allowance at the upper opening of the propeller tower 1, the following steps are included: By the height difference between the water line of the short nacelle 2 and the water line on the height benchmark, compare with the closing assembly line on the bottom plate of the short nacelle 2 to determine the allowance at the upper opening of the propeller tower 1. After determination, cut off the excess allowance at the upper opening of the propeller tower 1.

[0032] In some embodiments of the present invention, after the levelness adjustment at S5, recheck the height of the propulsion reducer base panel in the short nacelle 2, then use a rudder mold to recheck the installation height of the rudder in the short nacelle 2, and then use the plumb line method to recheck the perpendicularity of the flange end face at the front end of the short nacelle 2. The plumb bob is aligned with the detection line of the flange end face at the front end of the short nacelle 2 on the chassis frame 3.

[0033] As Figure 6 shown, in some embodiments of the present invention, at S7: before welding the propeller tower 1 and the short nacelle 2, clean the range of 20 mm to 30 mm of the joint between the short nacelle 2 and the propeller tower 1. Set a horizontal support 71 inside the short nacelle 2, set second diagonal braces 72 on both sides of the ground outside the short nacelle 2, and set a vertical support 73 at the center line of the bottom of the short nacelle 2 to reduce the shrinkage deformation generated during the welding of the closing seam between the propeller tower 1 and the short nacelle 2. The second diagonal braces 72 and the vertical support 73 are removed after welding is completed and before overall hoisting. The horizontal support 71 is removed during the overall assembly on the shipbuilding berth.

[0034] In some embodiments of the present invention, when welding the short nacelle 2 and the propeller tower 1, symmetrically weld both sides of the short nacelle 2 using MIG welding. After welding is completed, hoist the short nacelle 2 and the propeller tower 1 as a whole to the shipbuilding berth for general assembly.

[0035] In some embodiments of the present invention, after the welding between the propeller tower 1 and the short nacelle 2 is completed, use the deep penetration welding process to seal the process hole. Before sealing the process hole, the corresponding stiffeners inside the propeller tower 1 are installed synchronously. Prevent the welding between the propeller tower 1 and the short nacelle 2 from affecting the stiffeners inside the propeller tower 1.

[0036] The working process of the present invention is as follows: S01: Produce the propeller tower 1 and the short nacelle 2 respectively, and mark the reference lines on the propeller tower 1 and the short nacelle 2; S02: Set up the chassis frame 3 and height benchmarks within the site. Mark the detection lines on the chassis frame 3 and the height benchmarks, weld the chassis frame 3 to the site, and install a steel-aluminum composite material 31 at the top of the chassis frame 3 to support the nacelle tower 1. S03: Lift and fix the nacelle tower 1 onto the chassis frame 3 according to the detection lines. Determine the levelness of the four corners of the nacelle tower 1 through the horizontal base plane, then spot-weld the bottom of the nacelle tower 1 to the top of the steel-aluminum composite material 31. Mark one end of the outer plate of the nacelle tower 1 near the top of the steel-aluminum composite material 31 as the surplus area 11, and install the strengthening tooling 4 around the nacelle tower 1. S04: Set up the height benchmark on one side of the nacelle tower 1, and open a process hole at the transverse wall of the closed frame at the front end of the nacelle tower 1. S05: Lift and install the short nacelle 2 on the top of the nacelle tower 1. Install a wire-pulling frame inside the short nacelle 2, and pull out wires aligning with the propeller axis and the main engine axis along the center line of the nacelle tower 1 on the wire-pulling frame. Align the wires with the horizontal base plane to adjust the levelness of the short nacelle 2, and then fix the short nacelle 2 and the nacelle tower 1 with an adjustable fixing part 5, a turnbuckle. S06: Based on the height difference between the water line of the short nacelle 2 and the water line on the height benchmark, determine the surplus at the upper opening of the nacelle tower 1 by comparing with the assembly line on the bottom plate of the short nacelle 2. Draw the surplus line and cut according to the surplus line. S07: Clean the range of 20 mm - 30 mm at the joint between the short nacelle 2 and the nacelle tower 1. Set up a horizontal support 71 inside the short nacelle 2, set up second diagonal braces 72 on both sides of the ground outside the short nacelle 2, and set up a vertical support 73 at the center line of the bottom of the short nacelle 2. Weld the connection between the nacelle tower 1 and the short nacelle 2. After the welding between the nacelle tower 1 and the short nacelle 2 is completed, use the deep penetration welding to seal the process hole.

[0037] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A method for assembling a paddle tower and a short engine room of an air-cushion vehicle, characterized in that, Including the steps of: Marking reference lines on the blade tower and the short nacelle; Marking inspection lines on the chassis frame and the height benchmark respectively, and setting the chassis frame and the height benchmark on the site; Lifting and fixing the blade tower on the chassis frame, determining the position of the blade tower on the chassis frame according to the inspection lines, and installing strengthening tooling around the blade tower; Erecting the height benchmark on one side of the blade tower, and opening a process hole at the transverse wall of the closed frame at the front end of the blade tower; Lifting and installing the short nacelle on the top of the blade tower, determining the position of the short nacelle on the blade tower according to the inspection lines, and setting adjustable fixing parts to fixedly connect the short nacelle and the blade tower; Determining the surplus at the upper opening of the blade tower, drawing a surplus line and cutting the blade tower according to the surplus line; Welding the connection part between the blade tower and the short nacelle to complete the assembly of the blade tower and the short nacelle.

2. The assembly method of the paddle tower and short engine room of the hovercraft according to claim 1, characterized in that: The inspection lines of the chassis frame include the center line of the chassis frame, rib inspection lines and end face inspection lines for corresponding to the flange end face at the front end of the short nacelle, and the inspection lines on the height benchmark include a water line, a horizontal fold angle line of the blade tower outer plate and a propeller axis.

3. The assembling method of the paddle tower and the short engine room of the hovercraft according to claim 1, characterized in that, When setting the chassis frame on the site, it includes the following steps: spot-welding and fixing the chassis frame with the floor jack on the site, and a steel-aluminum composite material is arranged at the top of the chassis frame to bear the blade tower.

4. The assembling method of the paddle tower and the short engine room of the hovercraft according to claim 3, characterized in that, When lifting and fixing the blade tower on the chassis frame, it includes the following steps: determining the levelness of the four corners of the blade tower through a horizontal base surface, then spot-welding and fixing the bottom of the blade tower to the top of the steel-aluminum composite material, and one end of the bottom of the blade tower close to the top of the steel-aluminum composite material is marked as a surplus area.

5. The assembly method of the paddle tower and short engine room of the hovercraft according to claim 1, characterized in that: The strengthening tooling includes first diagonal braces arranged on both sides of the blade tower.

6. The assembly method of the paddle tower and short engine room of the hovercraft according to claim 1, characterized in that: The adjustable fixing parts include turnbuckles with both ends respectively fixed to the blade tower and the short nacelle.

7. The assembling method of the paddle tower and short engine room of the hovercraft according to claim 2, characterized in that: Before lifting the short nacelle, draw a closing assembly line on the bottom plate of the short nacelle corresponding to the blade tower to align with the blade tower during lifting; After lifting the short nacelle, install a wire-pulling frame in the short nacelle, and pull out a wire aligning with the propeller axis and a wire aligning with the main engine axis on the wire-pulling frame to align with the center line of the blade tower, and the wire is aligned with the horizontal base surface to adjust the levelness of the short nacelle.

8. The assembly method of the paddle tower and the short engine room of the hovercraft according to claim 7, characterized in that, When determining the surplus at the upper opening of the blade tower, it includes the following steps: determining the surplus at the upper opening of the blade tower by the height difference between the water line of the short nacelle and the water line on the height benchmark, and comparing with the closing assembly line on the bottom plate of the short nacelle.

9. The assembling method of the paddle tower and the short engine room of the hovercraft according to claim 7, characterized in that: After the levelness adjustment, recheck the height of the propulsion reducer base panel in the short nacelle, then use a rudder mold to recheck the rudder installation height in the short nacelle, and then use a plumb bob method to recheck the perpendicularity of the flange end face at the front end of the short nacelle.

10. The assembling method of the paddle tower and short engine room of the hovercraft according to claim 1, characterized in that: Before welding the blade tower and the short nacelle, set a horizontal support in the short nacelle, set second diagonal braces on both sides of the ground outside the short nacelle, and set a vertical support at the center line of the bottom of the short nacelle.

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