Inside the HMS Invincible

Class 4 Battle Cruiser 4 Units

Built by Lars Dahl


Larry built this ship in 2000 for his son Andy. Andy and Grant had been splitting time with Lars’ other I-Boat and the Bellephone. The boys always argued who should get the better ship since the Bellephone has a history of being under the water as much as on it. Lars purchased a Swampworks hull and started to copy the ship he had made out of wood several years before. He was surprised to find that the decks he had copied were a different size then the Swampy hull (Just a fraction of an inch). Turns out the there was a print difference in the two prints the ships were built from. This ship has been used off and on since then when the boys had their home work done and did not have to work. It made it to NATS 2001 & 2003.

Lars has Swampy props 1 ½” 4 blade 25 deg pitch. They are mounted nice and tight to the hull. The rudders are not straight. If they were changed the ship would turn better.

Here is a side view of the stern. The rudders could be a little closer to the props to help the turning of the ship. The prop shafts could also be more level. This would help turning and backwards speed. Having the props at and angle like this will pull the ship down into the water. Lars has drag props and drag disk on the outer shafts. This slows the ship down at high speed and helps with acceleration.

Here is a shot of the bow of the ship. Lars has the 3.5oz bottle and standard regulator at the very bow. He has his bottle labeled with his name, a good idea when attending large battles as everyone has the same types of bottles. He has a slight up angle from the bottle to the regulator to help keep the liquid CO2 in the bottle and not freezing up the regulator. He uses Presco Lock fittings and hose for the gas system. I have seen fewer failures with system then the Clippard hose and fittings. At the top is a hose going to the bow sidemount. It has a set of barbs and a couple to make easy disconnecting of the deck. At the left is the radio box. Lars is well known for his very water tight boxes. He routinely leaves his sunken ship at the bottom of the pond while battle continues. The left of the box has three popit valves for the guns. Compared to solenoids popits are much lower cost and lighter weight system for firing the guns. But popits will not fire guns as fast and fire them at a little lower pressure. The top center of the box has the pump switch. The top of the box (Labeled Tiger) has Lars’ unique way of getting electrical wires into and out of the box. He takes brass screws and glues them into the wood box then uses ring connectors at each end to pass the current through the box. This system makes for a water proof box but also has a high chance of electrical failure. Lars has had a few melt downs from bbs or brass nuts that short out between the exposed screws. The lid is held down by screws and sealed with silicone. Lars uses shower pan liner for his interior armor.

In the center of the ship you can see the accumulation tank on the radio box. It is made from ½” copper and has the male to male Clipard fitting soldered into place with the popits screwed into the fittings and silicone into the box. The Swampy pump is aft of the radio box. Lars has green capacitors soldered onto the motor to help with radio interference. The pump is held down with two hooks and a small bungee cord. Lars uses Molex connectors for the wiring connections. He has had many problems with the reliability of these connectors. He is much happier with the Deans Ultra connectors in his Tiger. Lars runs a 6 volt 12 amp hour SLA battery for this ship. Weight restrictions keep him from installing a larger SLA battery. NIMH batteries can provide more power for the same weight. They can provide enough power for this ship to use a Stinger pump motor, helping greatly with damage control and survivability. At the very left of the ship is the stern gun magazine and the drive motors. I like how Lars did the deck at the stern. He made the top deck cover the lower deck and left the lower deck open. This saves a little weight and makes the top of the ship look better as there is no seam in the upper deck. It would also be easy to use a slide system to hold the upper deck on with the cross brace at the stern.

Here we can see how the bow sidemount the fits in on the side of the bottle. You can see the two part slide on the deck and how it fits on to the sub deck.

Here is the middle gun that can be swung around to be used as a bow or stern gun. It is mounted as a bow gun right now with a round hook holding the barrel in place.

A view of the stern interior. The motors are mounted to the Traxass Villain gear boxes. The rudder servo is in a water tight box. The top of the box is cut to fit into the sub deck. It holds itself in place and is easily removed for service. The rudders are moved with an arm on the post. A piece of interior armor is between the posts to prevent bbs from passing through. This has left the rudder post exposed to bbs entering the stern. This ship has had issues with the rudder control. It is possible that a lucky bb hit something back here and knocked it lose.


This is a photo of the stern sidemount. Like the bow gun it is held in place with a ring hook. None of Lars guns have plastic protectors on the barrels. This is a must to protect the brass or stainless steel from bbs. He has placed a protective cover over the magazine.