Torpedo Shutters and how to move them

This seems to be a huge problem for a lot of people, which is interesting to me as, in the grand scheme of things, it's one of the least technical challenges that an RC submarine model may pose to a builder.

So, in response to a slough of questions on this topic, I thought I'd pen a blog article (just to test who actually searches them before reaching out to me directly for the easy answers).

Here we go..

Okay, first off, realize that there are a number of ways to make the torpedo shutters on your model functional. The method that I am showing here is just one of many, albeit one that I have success with and am a big proponent of.

The layout is quite simple. You put a hinge point on the aft side of each shutter, connecting top and bottom shutters if you have more than one per side. From that hinge point, you have an intermediate linkage that angles back toward the stern and also toward the centerline of the boat, until you reach a point where both left and right linkage meet.

Now, you put another hinge point here. We are not talking rocket science, people. Just a simple pin going through two pieces of flat stock. to that hinge point, you attach your main servo linkage, which runs straight back to your cylinder at the approximate center of the boat. You'll want to put this linkage rod in a bushing or a sleeve in order to maintain pure linear movement forward and back without any slop. If you don't, your shutters will still open and close, but one side might do so first until it bottoms out, then the other side will. Putting the guide on the main linkage rod keeps the movement symmetrical on both sides.

Now, as the main linkage moves forward and back, it translates into perpendicular force thanks to our hinge points, pressing the shutters outward until they seat against the hull.

Now, at this point, I'm guessing you're completely lost and ready to click open and email to me in order to clarify what I'm talking about. Well, fear not, for I have also taken the time to draft a schematic of what I'm talking about. If you can't figure things out from this, well.. I suggest taking up a new hobby like... crochet, or maybe ping pong.

A simple top-down view for you:

And how about this fancy 3D-looking version!?:

Mike Martin did a similar set up for his beautiful 1:50 scale British Upholder submarine. He put together a video of that system in operation. You can view that here.

Well, there you have it! Torpedo shutters 101 for those of you wanting to know how I typically do it.

Now, I realize that there are a ton of unconventional shutter opening mechanics in subs, and this method may not work for them. Those challenges will need to be met one at a time on an individual basis. What I'm showing here is good for a lot of WW2-era boats, and will take you far. Happy building!

Bob Martin

the RCSubGuy