Building a Lego-powered Submarine 2.0 — magnetic couplings

This RC sub has magnetic couplings to transmit torque through the walls. No need to drill holes = no leaks. At the end I test it in a swimming pool. Enjoy!

Differences to the first sub https://www.youtube.com/watch?v=tGEZApd9MMk
-rectangular hull (need flat walls for magnetic couplings)
-snap-and-lock lid (more reliable, less leakage)
-bigger motors, more motors, more propellers
-depth control using propellers (IMO more accurate compared to a syringe ballast tank)
-lead pellets for ballast (easier to adjust, both shape and weight, compared to steel plates)
-captain (thanks everyone for pointing out this obvious missing part :))

The submarine specs:
Displacement: 2.7 kg (6.0 lb)
Test depth: 1.5 m (4.9 ft)
Hull: glass food container (IKEA 365+ 1.8l), plastic lid
Motors: 3x Lego XL-motor (8882-1)
Magnetic couplings: K&J Magnetics R844-N52 neodymium magnet, TapeCase 423-5 UHMW Tape
Propellers: Lego propeller blade (2952), Lego liftarms
Radio control: 27 MHz controller dissembled from a toy submarine (Zantec Mini RC U Boot), L298 H-bridge to drive motors
Power supply: 9V Lego battery box for the motors, 3.7V Li-Po for the RC
Onboard camera: Faironly Firefly Q6
Pressure sensor: Jolly Logic Altimeter One

Link to the magnets used in the couplings:
https://www.kjmagnetics.com/proddetail.asp?prod=R844-N52

Music:
Tommy Baynen — Laminar Flow
https://colorize.ffm.to/encolor222
https://www.youtube.com/watch?v=UPdR8lh4a1o
https://soundcloud.com/tommybaynen

( ! ) Warning: Invalid argument supplied for foreach() in /home/domains/malitikov.ru/public_html/wp-content/themes/malitikov/single.php on line 44
Call Stack
#	Time	Memory	Function	Location
1	0.0000	350472	{main}( )	.../index.php:0
2	0.0000	350752	require( '/home/domains/malitikov.ru/public_html/wp-blog-header.php )	.../index.php:17
3	0.1899	8503176	require_once( '/home/domains/malitikov.ru/public_html/wp-includes/template-loader.php )	.../wp-blog-header.php:19
4	0.1917	8507384	include( '/home/domains/malitikov.ru/public_html/wp-content/themes/malitikov/single.php )	.../template-loader.php:106

Мы рекомендуем

( ! ) Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 20480 bytes) in /home/domains/malitikov.ru/public_html/wp-includes/class-wpdb.php on line 2322
Call Stack
#	Time	Memory	Function	Location
1	0.0000	350472	{main}( )	.../index.php:0
2	0.0000	350752	require( '/home/domains/malitikov.ru/public_html/wp-blog-header.php )	.../index.php:17
3	0.1899	8503176	require_once( '/home/domains/malitikov.ru/public_html/wp-includes/template-loader.php )	.../wp-blog-header.php:19
4	0.1917	8507384	include( '/home/domains/malitikov.ru/public_html/wp-content/themes/malitikov/single.php )	.../template-loader.php:106
5	0.5186	22749712	WP_Query->__construct( $query = ['post_type' => 'post', 'post_status' => 'publish', 'fields' => 'ids', 'posts_per_page' => -1, 'no_found_rows' => TRUE, 'orderby' => 'none'] )	.../single.php:65
6	0.5186	22749712	WP_Query->query( $query = ['post_type' => 'post', 'post_status' => 'publish', 'fields' => 'ids', 'posts_per_page' => -1, 'no_found_rows' => TRUE, 'orderby' => 'none'] )	.../class-wp-query.php:4081
7	0.5186	22749712	WP_Query->get_posts( )	.../class-wp-query.php:3949
8	0.5191	22761576	wpdb->get_col( $query = 'SELECT wp_posts.ID\n\t\t\t\t\t FROM wp_posts \n\t\t\t\t\t WHERE 1=1 AND wp_posts.post_type = \'post\' AND ((wp_posts.post_status = \'publish\'))\n\t\t\t\t\t \n\t\t\t\t\t \n\t\t\t\t\t ', $x = ??? )	.../class-wp-query.php:3300
9	0.5191	22761576	wpdb->query( $query = 'SELECT wp_posts.ID\n\t\t\t\t\t FROM wp_posts \n\t\t\t\t\t WHERE 1=1 AND wp_posts.post_type = \'post\' AND ((wp_posts.post_status = \'publish\'))\n\t\t\t\t\t \n\t\t\t\t\t \n\t\t\t\t\t ' )	.../class-wpdb.php:3107
10	4.3092	817990872	mysqli_fetch_object( $result = class mysqli_result { public $current_field = 0; public $field_count = 1; public $lengths = [0 => 7]; public $num_rows = 1517174; public $type = 0 } )	.../class-wpdb.php:2322