- Inside of the DKM Bismarck (Charlie) -

DKM Bismarck – built by Charlie Stephens

6.5 units, 24 seconds, German Battleship

Pictures from Nats 2021, owned by Craig Singer

Craig’s Bismarck is set up with 2 pumps, 2 stern sidemounts, 1 bow sidemount, and 1 bow “funny” gun. He acquired it from Charlie, who used the more traditional twin stern gun approach with a single stern sidemout. The decks are fiberglass board. The super structure is a combination of molded, fiberglass, and 3D printed. The hull is fiberglass. It weighed in around 37 lbs. The Bismark is a very large boat with a heavy amount of fire power. It is important to be very aware of freeboard during the build process though the armor belt stringer provides a degree of midship protection from aboves as the distance from the subdeck to the stringer is big enough for bbs to enter but not that big. The main disadvantage to the Bismarck is that the 3 shafts instead of 4. Traditionally only the center was powered, which makes acceleration and backing up less ideal but turning better. For a period of time this was compensated for by running the outboard 2 shafts in reverse only but this was ultimately outlawed. A compromise to this principle, used by this ship, is to run all 3 shafts in some combination of full in one direction and lower speed in the other direction in a way which drives forward primarily on the center shaft and reverse primarily from the outer 2 shafts.

The bow section of deck houses the guns, solenoids, and firing boards all mounted to the deck itself. This can cause stability problems in smaller boats due to the higher placed weight when using this approach. The bottle sits under this section, 7 oz tank. Evidently the internal armor is trustworthy as the magazines are not protected, I would suggest spending the minimal extra time and money to wrap them in plastic coating so a stray bb wouldn’t cause feeding problems. 1/4 inch ID high flow hose goes into the bottom of the gun, 1/16 hose goes from the cap to the back of the magazine.

Similarly, the stern section has the guns, solenoid, and firing board mounted to the bottom of the deck. You can get a sense for how meticulous he was in getting everything to sit where he wanted it, ultimately using zip ties for a firm but adjustable mounting, which I generally like to use as well. The quick disconnects are gaining popularity, in the past they were less reliable and would fail however that hasn’t been as big of a problem with this style of connector. In the far stern the rudder setup includes an extra gear in order to get a full size water proof servo installed and not have to worry about height. The deck is held down by inlayed magnets.

The mid sections house areas for waterproofed electronics and the batteries. Batteries are 7.4V LiFePO with a total of 16 amp-hours which for other battery chemistries would be a bit lite, but the newer batteries provide a flat discharge rate and the brushless components are extremely efficient. There is hose to the regulator but brass tube running to the bow and stern that later plug into a piece of hose. I’m not sure the rationale for this other than a sturdy piece of connection point, the disadvantage is inflexibility. You can see the central prop has a brushless motor and the outer 2 are brushed. The pumps are side by side rather than inline. Water channeling and the lead in the bottom of the ship are difficult to appreciate in these pictures.

The I-Beam shaped rudders are designed to control the prop wash better. Generally speaking this ship will turn very well as compared to most other ships this size with 2 primary drive props. The prop is 2.25 inches and the outer props are 1.5 inches.

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