Assembly method of propeller tower and short nacelle of hovercraft

Abstract

The present 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. By setting a detection line reference system of a chassis frame and a height benchmark during a ground prefabrication stage, the positioning and adjustment of the propeller tower and the short engine room can be completed completely in a low-altitude site, thereby avoiding the operational risk of repeatedly erecting and dismantling scaffolding during high-altitude lifting of a slipway in traditional processes. A three-dimensional spatial positioning network is constructed by combining the plane reference of the chassis frame and the vertical reference of the height benchmark, thereby reducing the precision error during the assembly process. The high-altitude closing operation in the traditional slipway stage is moved forward to a ground site for completion, so that the short engine room-propeller tower module only needs a single lifting and positioning when the final hull is loaded. This shortens the slipway processing cycle and further reduces the production cost of the hovercraft.

Description

Technical Field

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

[0002] In hovercraft construction, the propeller tower and short engine room sections serve as the core support structures for the propulsion system and main engine equipment. Their fabrication precision and overall assembly quality directly determine the propulsion system's operational efficiency and overall vessel performance. These two specialized sections are typically prefabricated independently on dedicated jigs and ultimately assembled with the main hull to achieve high-precision assembly.

[0003] The existing process utilizes a segmented prefabrication-slipway assembly model, meaning that after the propeller tower and short engine room are independently fabricated on dedicated cradles, they must wait until the hull enters the slipway for hoisting and positioning. Because the composite structure's designed installation location is on the superstructure deck, significant technical bottlenecks exist, such as difficulty constructing an aerial work platform and obstructed transmission of spatial positioning references. Specifically, aerial suspension operations require repeated erection and dismantling of multi-layer scaffolding systems, resulting in extended auxiliary construction periods and operational risks. Segmented assembly requires multiple rounds of precision adjustments, making welding deformation control difficult and resulting in a high rework rate. These process flaws not only extend the construction cycle by multiple working days, but also result in insufficient pass rates for key indicators such as the flatness of the propulsion system base and the concentricity of the axis, seriously impacting the assembly accuracy and operational stability of the hovercraft's power system. While the industry is currently attempting to optimize this through improved welding sequences and the addition of temporary supports, these efforts have failed to fundamentally address the systemic process flaws inherent in aerial assembly operations. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for assembling the propeller tower and short engine room of an air cushion vehicle, so as to move the high-altitude closure operation in the traditional slipway stage to the ground site for completion, so that the short engine room-propeller tower module only needs a single lifting and positioning when the final hull is loaded, thereby shortening the slipway processing cycle and further reducing the production cost of the air cushion vehicle.

[0005] In order to achieve the above object, the present invention provides a method for assembling a propeller tower and a short nacelle of an air cushion vehicle, comprising the following steps:

[0006] Mark the datum lines on the propeller tower and short nacelle;

[0007] Marking detection lines on the chassis frame and the height pole respectively, and placing the chassis frame and the height pole on the site;

[0008] The propeller tower is hoisted and fixed on the chassis frame, and the position of the propeller tower on the chassis frame is determined according to the detection line, and reinforcement tooling is installed around the propeller tower;

[0009] The height benchmark is erected on one side of the paddle tower, and a process hole is opened on the horizontal wall of the closed frame at the front end of the paddle tower;

[0010] The short nacelle is hoisted and arranged on the top of the propeller tower, and the position of the short nacelle on the propeller tower is determined according to the detection line, and an adjustable fixing member is provided to fix the short nacelle and the propeller tower;

[0011] Determine the margin of the upper opening of the propeller tower, draw a margin line and cut the propeller tower according to the margin line;

[0012] The connection between the propeller tower and the short nacelle is welded to complete the assembly of the propeller tower and the short nacelle.

[0013] Compared with the prior art, the assembly method of the propeller tower and short engine room of an air cushion vehicle in an embodiment of the present invention has the following beneficial effects: the present application accurately positions the propeller tower and the short engine room by setting a chassis frame and a height benchmark, so that the propeller tower and the short engine room are accurately positioned after hoisting, and then the short engine room and the propeller tower are welded and assembled, so that the short engine room and welding are pre-assembled before the slipway is built; the present application sets a detection line reference system of the chassis frame and the height benchmark in the ground prefabrication stage, so that the positioning and adjustment of the propeller tower and the short engine room are completed completely in a low-altitude site, avoiding the operational risk of repeated erection and dismantling of scaffolding during high-altitude hoisting of the slipway in traditional processes, and constructs a three-dimensional spatial positioning network based on the plane reference of the chassis frame and the vertical reference of the height benchmark, thereby reducing the accuracy error in the combination process, and moving the high-altitude closing operation of the traditional slipway stage to the ground site for completion, so that the short engine room-propeller tower module only needs a single hoisting and positioning when the final hull is loaded, shortening the slipway processing cycle and further reducing the production cost of the air cushion vehicle.

[0014] The assembly method of the propeller tower and short nacelle of an air cushion vehicle in an embodiment of the present invention, the detection lines of the chassis frame include the center line of the chassis frame, the rib detection line and the end face detection line corresponding to the flange end face of the front end of the short nacelle, and the detection lines on the height benchmark include the waterline, the horizontal angle line of the propeller tower outer plate and the propeller axis.

[0015] The assembly method of the propeller tower and short nacelle of the hovercraft of an embodiment of the present invention includes the following steps when the chassis frame is set on the site: the chassis frame is spot-welded to the ground on the site, and a steel-aluminum composite material is provided on the top of the chassis frame to support the propeller tower.

[0016] The assembly method of the propeller tower and short nacelle of the hovercraft according to an embodiment of the present invention includes the following steps when fixing the propeller tower to the chassis frame: determining the horizontality of the four corners of the propeller tower through a horizontal base surface, and then spot welding the bottom of the propeller tower to the top of the steel-aluminum composite material, and the end of the bottom of the propeller tower close to the top of the steel-aluminum composite material is marked as a margin area.

[0017] In the assembly method of the propeller tower and the short nacelle of the hovercraft according to the embodiment of the present invention, the reinforcing tooling includes a first diagonal brace provided on both sides of the propeller tower.

[0018] In the assembly method of the propeller tower and the short nacelle of the hovercraft according to the embodiment of the present invention, the adjustable fixing member includes a turnbuckle bolt whose two ends are respectively fixed to the propeller tower and the short nacelle.

[0019] In an assembly method of a paddle tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention, before hoisting the short nacelle, a closing assembly line with the paddle tower is marked on the bottom plate of the short nacelle so as to align the paddle tower during hoisting;

[0020] After the short nacelle is hoisted, a wire draw frame is installed in the short nacelle, and steel wires aligned with the propeller axis and the main engine axis are pulled out on the wire draw frame in alignment with the center line of the propeller tower. The steel wires are aligned with the horizontal base surface to adjust the horizontality of the short nacelle.

[0021] The assembly method of the propeller tower and short nacelle of the hovercraft in an embodiment of the present invention, in determining the margin of the upper opening of the propeller tower, includes the following steps: determining the margin of the upper opening of the propeller tower by comparing the height difference between the waterline of the short nacelle and the waterline on the height benchmark with the closing assembly line on the bottom plate of the short nacelle.

[0022] The assembly method of the propeller tower and short nacelle of the hovercraft in an embodiment of the present invention is as follows: after the horizontality is adjusted, the height of the propulsion reducer base panel in the short nacelle is reviewed, and then the rudder model is used to review the rudder installation height in the short nacelle, and then the plumb bob method is used to review the verticality of the flange end face at the front end of the short nacelle.

[0023] The assembly method of the propeller tower and short nacelle of the hovercraft in an embodiment of the present invention is as follows: before welding the propeller tower and the short nacelle, a horizontal support is set in the short nacelle, a second diagonal brace is set on the ground on both sides outside the short nacelle, and a vertical support is set at the center line of the bottom of the short nacelle.

[0024] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of an assembly method of a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of a chassis frame of an assembly method of a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0027] Figure 31 is a schematic diagram of the assembly of a propeller tower and a chassis frame of a method for assembling a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0028] Figure 4 1 is a schematic diagram of a first diagonal brace of a method for assembling a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of an adjustable fixing member of an assembly method of a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0030] Figure 6 1. It is a schematic diagram of reinforcement before welding of an assembly method of a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention;

[0031] Figure 7 Schematic diagram of a flow chart of a method for assembling a propeller tower and a short nacelle of an air cushion vehicle according to an embodiment of the present invention

[0032] In the figure, 1. propeller tower; 11. margin area; 2. short nacelle; 3. chassis frame; 31. steel-aluminum composite material; 4. reinforcement tooling; 5. adjustable fixings; 71. horizontal support; 72. second diagonal brace; 73. vertical support. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] like Figure 1 and Figure 7 As shown, a method for assembling a propeller tower and a short nacelle of an air cushion vehicle according to a preferred embodiment of the present invention comprises the following steps:

[0038] S1: Mark the reference lines on the propeller tower 1 and the short nacelle 2;

[0039] S2: Mark the detection lines on the chassis frame 3 and the height benchmark respectively, and set the chassis frame 3 and the height benchmark on the site;

[0040] S3: hoist and fix the propeller tower 1 on the chassis frame 3, determine the position of the propeller tower 1 on the chassis frame 3 according to the detection line, and install the reinforcement tooling 4 around the propeller tower 1;

[0041] S4: erect a height benchmark on one side of the propeller tower 1, and open a process hole on the horizontal wall of the closed frame at the front end of the propeller tower 1;

[0042] S5: hoist the short nacelle 2 to the top of the propeller tower 1, and determine the position of the short nacelle 2 on the propeller tower 1 according to the detection line, and set the adjustable fixing member 5 to fix the short nacelle 2 and the propeller tower 1;

[0043] S6: Determine the allowance of the upper opening of the propeller tower 1, draw the allowance line and cut the propeller tower according to the allowance line;

[0044] S7: Weld the connection between the propeller tower 1 and the short nacelle 2 to complete the assembly of the propeller tower 1 and the short nacelle 2.

[0045] The present application sets a chassis frame 3 and a height benchmark to accurately position the propeller tower 1 and the short engine room 2, so that the propeller tower 1 and the short engine room 2 are accurately positioned after hoisting, and then the short engine room 2 and the propeller tower 1 are welded and assembled, so that the short engine room 2 and welding are completed in advance before the slipway is built; the present application sets a detection line reference system of the chassis frame 3 and the height benchmark in the ground prefabrication stage, so that the positioning and adjustment of the propeller tower 1 and the short engine room 2 are completed completely in a low-altitude site, avoiding the operational risk of repeated erection and dismantling of scaffolding during high-altitude hoisting of the slipway in traditional processes, and constructs a three-dimensional spatial positioning network based on the plane reference of the chassis frame 3 and the vertical reference of the height benchmark, thereby reducing the accuracy error in the combination process, and moving the high-altitude closure operation of the traditional slipway stage to the ground site for completion, so that the short engine room 2-propeller tower 1 module only needs a single hoisting and positioning when the final hull is loaded, shortening the slipway processing cycle and further reducing the production cost of the hovercraft.

[0046] In some embodiments of the present invention, during site preparation, the assembly site should be kept clean, free of easily contaminated materials, and should not be mixed with steel structures for construction. Humidity and wind speed sensors should be installed to ensure that the relative humidity is less than 80% and the wind speed is less than 0.5 m / s. Welding should be stopped if the relative humidity exceeds 90%. The chassis frame 3 is made of steel.

[0047] In some embodiments 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 corresponding to the flange end face of the front end of the short nacelle 2, which are used for positioning the propeller tower 1 and the short nacelle 2 in the horizontal direction. The detection lines on the height benchmark include the waterline, the horizontal angle line of the outer plate of the propeller tower 1 and the propeller axis, which are used for positioning the propeller tower 1 and the short nacelle 2 in the vertical direction.

[0048] like Figure 2 and Figure 3 As shown, 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 to the ground on the site to ensure that the chassis frame 3 is firmly fixed during the assembly process, and the chassis frame 3 can also be kept horizontal with the ground to prevent affecting the accurate positioning of the propeller tower 1 and the short nacelle 2; a steel-aluminum composite material 31 is provided on the top of the chassis frame 3 to support the propeller tower 1.

[0049] In some embodiments of the present invention, in S3: when fixing the propeller tower 1 to the chassis frame 3, the following steps are included: determining the horizontality of the four corners of the propeller tower 1 through a horizontal base surface, and this process is adjusted by setting basket bolts at the connection between the propeller tower 1 and the chassis frame 3; specifically, the corner of the propeller tower 1 is aligned with the horizontal corner line of the height benchmark. Then, the bottom of the propeller tower 1 is spot-welded to the top of the steel-aluminum composite material 31; specifically, the propeller tower 1 includes an outer plate, and the end of the outer plate close to the top of the steel-aluminum composite material 31 is marked as a margin area 11. The margin area 11 is used to be cut off after the welding of the propeller tower 1 and the short nacelle 2 is completed, so that the propeller tower 1 is released from the chassis frame 3.

[0050] like Figure 4 As shown, in some embodiments of the present invention, the reinforcing tooling 4 includes a first diagonal brace arranged on both sides of the paddle tower 1, and there are multiple first diagonal braces on both sides of the paddle tower 1. The multiple first diagonal braces are evenly arranged along the length direction of the paddle tower 1 so that their support for the paddle tower 1 remains firm.

[0051] like Figure 5As shown, in some embodiments of the present invention, the adjustable fixing part 5 includes a basket bolt whose two ends are respectively fixed to the propeller tower 1 and the short nacelle 2. Specifically, a protrusion is provided at the connection between the propeller tower 1 and the short nacelle 2 to connect the basket bolt. The basket bolt can adjust the distance between its two ends through the sliding of the internal component, so as to achieve the effect of adjusting the position between the propeller tower 1 and the short nacelle 2. The adjustment is performed by the basket bolt, which is easy to use and has sufficient strength.

[0052] In some embodiments of the present invention, in S5: before hoisting the short nacelle 2, a closing assembly line with the propeller tower 1 is marked on the bottom plate of the short nacelle 2 so as to align the propeller tower 1 during hoisting and to perform margin cutting at the closing position before welding;

[0053] After the short nacelle 2 is hoisted, in S5: a wire draw frame is installed in the short nacelle 2. On the wire draw frame, a steel wire aligned with the propeller axis and the main engine axis is pulled out in line with the center line of the propeller tower 1. The steel wire is aligned with the horizontal base surface to adjust the level of the short nacelle 2. Specifically, the steel wire is extended to the propeller axis and the main engine axis at the height benchmark. The level of the steel wire is detected to detect the level of the end integration. The level emitted by the laser represents the horizontal line. If the steel wire is not parallel or colinear with the laser, the level is insufficient and a basket bolt is required to further adjust the relative position of the short nacelle 2 and the propeller tower 1.

[0054] In some embodiments of the present invention, in S6: in determining the margin of the upper opening of the propeller tower 1, the following steps are included: by comparing the height difference between the waterline of the short nacelle 2 and the waterline on the height benchmark, the closing assembly line on the bottom plate of the short nacelle 2 is used to determine the margin of the upper opening of the propeller tower 1, and after determination, the excess margin of the upper opening of the propeller tower 1 is cut.

[0055] In some embodiments of the present invention, after the horizontality is adjusted in S5, the height of the propulsion reducer base panel in the short nacelle 2 is reviewed, and then the rudder model is used to review the rudder installation height in the short nacelle 2. Then, the plumb bob method is used to review the verticality of the flange end face at the front end of the short nacelle 2, and 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.

[0056] like Figure 6 As shown, in some embodiments of the present invention, in S7: before welding the propeller tower 1 and the short nacelle 2, the 20mm to 30mm range of the joint between the short nacelle 2 and the propeller tower 1 is cleaned, a horizontal support 71 is set inside the short nacelle 2, a second diagonal support 72 is set on the ground on both sides of the short nacelle 2, and a vertical support 73 is set at the center line of the bottom of the short nacelle 2 to reduce the shrinkage deformation caused by welding the joint between the propeller tower 1 and the short nacelle 2. The second diagonal support 72 and the vertical support 73 are removed after welding is completed and before the overall hoisting, and the horizontal support 71 is removed when the overall ship is loaded on the slipway.

[0057] In some embodiments of the present invention, when welding the short nacelle 2 and the propeller tower 1, MIG welding is used to perform symmetrical welding on both sides of the short nacelle 2. After welding is completed, the short nacelle 2 and the propeller tower 1 are hoisted as a whole to the slipway for final assembly.

[0058] In some embodiments of the present invention, after the welding between the propeller tower 1 and the short nacelle 2 is completed, the process hole is resealed by deep penetration welding. Before resealing the process hole, the corresponding frame materials inside the propeller tower 1 are simultaneously installed to prevent the welding between the propeller tower 1 and the short nacelle 2 from affecting the frame materials inside the propeller tower 1.

[0059] The working process of the present invention is:

[0060] S01: Produce propeller tower 1 and short nacelle 2 separately, and mark the reference lines on propeller tower 1 and short nacelle 2;

[0061] S02: Set up a chassis frame 3 and a height benchmark in the site, mark the detection line on the chassis frame 3 and the height benchmark, weld the chassis frame 3 to the site, and set a steel-aluminum composite material 31 on the top of the chassis frame 3 to support the propeller tower 1;

[0062] S03: Hoist and fix the propeller tower 1 to the chassis frame 3 according to the inspection line. Use the horizontal base surface to determine the levelness of the four corners of the propeller tower 1. Then, spot weld the bottom of the propeller tower 1 to the top of the steel-aluminum composite material 31. The end of the outer plate of the propeller tower 1 close to the top of the steel-aluminum composite material 31 is marked as the margin area 11. Install the reinforcement tooling 4 around the propeller tower 1.

[0063] S04: erecting a height benchmark on one side of the propeller tower 1, and opening a process hole on the horizontal wall of the closed frame at the front end of the propeller tower 1;

[0064] S05: Hoist the short nacelle 2 to the top of the propeller tower 1, install a cable tie rack inside the short nacelle 2, align the centerline of the propeller tower 1 with the steel wires aligned with the propeller axis and the main engine axis on the cable tie rack, align the steel wires with the horizontal base surface to adjust the level of the short nacelle 2, and then fix the short nacelle 2 and the propeller tower 1 with the adjustable fixing member 5 turnbuckle bolts;

[0065] S06: Determine the upper opening margin of the propeller tower 1 by comparing the height difference between the waterline of the short nacelle 2 and the waterline on the height benchmark with the closing assembly line on the bottom plate of the short nacelle 2, draw a margin line, and perform cutting according to the margin line;

[0066] S07: Clean the 20mm to 30mm range of the joint between the short nacelle 2 and the propeller tower 1, set a horizontal support 71 inside the short nacelle 2, set a second diagonal support 72 on the ground on both sides outside the short nacelle 2, and set a vertical support 73 at the center line of the bottom of the short nacelle 2. Weld the connection between the propeller tower 1 and the short nacelle 2. After the welding between the propeller tower 1 and the short nacelle 2 is completed, use deep penetration welding to reseal the process hole.

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for assembling a propeller tower and a short nacelle of a hovercraft, characterized in that: Including steps: Mark the datum lines on the propeller tower and short nacelle; Marking detection lines on the chassis frame and the height pole respectively, and placing the chassis frame and the height pole on the site; The propeller tower is hoisted and fixed on the chassis frame, and the position of the propeller tower on the chassis frame is determined according to the detection line, and reinforcement tooling is installed around the propeller tower; The height benchmark is erected on one side of the paddle tower, and a process hole is opened on the horizontal wall of the closed frame at the front end of the paddle tower; The short nacelle is hoisted and arranged on the top of the propeller tower, and the position of the short nacelle on the propeller tower is determined according to the detection line, and an adjustable fixing member is provided to fix the short nacelle and the propeller tower; Determine the margin of the upper opening of the propeller tower, draw a margin line and cut the propeller tower according to the margin line; The connection between the propeller tower and the short nacelle is welded to complete the assembly of the propeller tower and the short nacelle.

2. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 1, characterized in that: The detection lines of the chassis frame include the center line of the chassis frame, the rib detection line and the end face detection line corresponding to the flange end face of the front end of the short nacelle. The detection lines on the height benchmark include the waterline, the horizontal angle line of the propeller tower outer plate and the propeller axis.

3. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 1, characterized in that: When the chassis frame is set on the site, the following steps are included: the chassis frame is fixed to the ground on the site by spot welding, and a steel-aluminum composite material is set on the top of the chassis frame to support the propeller tower.

4. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 3, characterized in that: When the paddle tower is hoisted and fixed on the chassis frame, the following steps are included: determining the horizontality of the four corners of the paddle tower through a horizontal base surface, and then spot welding the bottom of the paddle tower to the top of the steel-aluminum composite material, and the end of the bottom of the paddle tower close to the top of the steel-aluminum composite material is marked as a margin area.

5. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 1, characterized in that: The reinforcement tooling includes a first diagonal brace arranged on both sides of the propeller tower.

6. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 1, characterized in that: The adjustable fixing member includes a basket bolt with two ends respectively fixed to the propeller tower and the short nacelle.

7. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 2, characterized in that: Before hoisting the short nacelle, marking an assembly line for the short nacelle and the propeller tower on the bottom plate of the short nacelle so as to align the propeller tower during hoisting; After the short nacelle is hoisted, a wire draw frame is installed in the short nacelle, and steel wires aligned with the propeller axis and the main engine axis are pulled out on the wire draw frame in alignment with the center line of the propeller tower. The steel wires are aligned with the horizontal base surface to adjust the horizontality of the short nacelle.

8. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 7, characterized in that: When determining the margin of the upper opening of the propeller tower, the following steps are included: by comparing the height difference between the waterline of the short nacelle and the waterline on the height benchmark, the closing assembly line on the bottom plate of the short nacelle is used to determine the margin of the upper opening of the propeller tower.

9. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 7, characterized in that: After adjusting the horizontality, check the height of the propulsion reducer base panel in the short nacelle, then use the rudder model to check the rudder installation height in the short nacelle, and then use the plumb bob method to check the verticality of the flange end face at the front end of the short nacelle.

10. The method for assembling a propeller tower and a short nacelle of a hovercraft according to claim 1, characterized in that: Before welding the propeller tower and the short nacelle, a horizontal support is provided in the short nacelle, a second diagonal support is provided on the ground on both sides outside the short nacelle, and a vertical support is provided at the center line of the bottom of the short nacelle.

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