FreekS

I thought that was a coffee mug until I zoomed in!

Both boats in this pic operate close to their scaled max depth, for O-13 around 60 meter (one boat length) and skipjack likely over 200m. It’s also amazing to realise “only” 25 years separate building these two subs!

It will be a real challenge to realistically model that smoke!

I’ve made the first international trip with O-13, to Nürnberg in South of Germany where there was a big submarine meet in a pool. Hung a GoPro over the Edge of the basin and spend two days sailing. Done quite a lot of optimising ballast, tweaking the movement of the front diveplanes and much more. Also replaced the props with nylon/carbon 3D printed ones with much smaller pitch, to sail slowly enough at periscope depth. And found room to install an automatic leveler. Now the boat is near stable at periscope depth with the rear planes being controlled by the leveler and both front and rear planes also by the transmitter.

Especially if you use an airbrush!

Piets O-19 was very nice. We exchanged some details drawings at the time - I was building O-1. I’ve not heard from him in a long time ….

Thanks mcb! it does add to the enjoyment of building, but building subs seems to me to be less risky than planes or helos. With subs, the main risk is losing sight of it when it’s submerged. That really raises the heartrate! As long as the boat is well waterproof (and possibly with a water in the boat alarm), the consequence of a problem is that the boat will fall still, sit on the bottom or float. At least it won’t crash!! Mostly I sail at a sailing club where when needed there is a boat, a wading suit or even fishing gear to go look for a lost sub. The key is to always keep your eyes on the periscope! but yes, the risk is part of the fun….

The “leak” turned out to be an “error in thinking”, water dripped out of the flood zones, not the watertight compartment! Decals replaced and in clear coated with a brush (instead of airbrush) hopefully has a thicker protective coating. The boat was a bit heavy after so put a bit of floating foam under the deck. then today we went with a small group to my model sailing club. Sunny weather, about 1-3 feet of pretty clear water, could not be better. amd the boat sailed - a bit too fast, very easy to dive and surface and a huge turning radius. Still work to be done, but the boat is fully under control and I’m very happy!

Yes it is difficult, frequently I have to reach and change a component worked on months ago that is no longer so accessible. Now that the cranes and net cutter are mounted on the deck, I needed to make a rig to safely work on the components under the deck section, for fear of damage. But pre-thinking those things is also part of the fun…

The past weeks were about making everything ready for balance tests in water following the rough trimming I had done in my bath and the one night sailing. For that I needed the weight (distribution) to be close to final. Ive painted and mounted the net cutter, turned two periscopes on my mini-lathe, made an aft mast that will double as the air exit from the tank, made the floats to close all 4 hatches when the boat dives, and mounted the bridge equipment (radio direction finder, compass and helm). Still some smaller details to do but the boat looks great! In my plexiglass test tank the boat lies level on the waterline. I would prefer a slightly higher nose-up attitude. Then started the pump to fill the tank. The pump is programmed to stop after 27seconds, which was enough to fill the tank in earlier “partial” tests. Now it brought the boat to “decks awash” but not to neutral buoyancy. Took the boat out, weighed it on a kitchen scale (3,9kg) and then emptied the tank (now 3,4kg). As the tank volume is 600ml the tank was clearly not full. Maybe the air exiting through the mast is giving some back pressure. On repeating this twice the boat came lower in the water (and more nose heavy). Now the boat with full tank was 4,1kg. Do I have a leak or did I fill the tank more? Took the boat out, there was a small amount of water in the water tight compartment (may 10-20ml), not enough to trigger to water sensors. Ok, it’s clear that I need to change the tank filling procedure (fill longer and end with a slow top up fill?) to try to get the tank totally full always. 100 gram more or less has a huge effect on the stability underwater. There is no point in adding or moving weights until the tank is always full. I have a list of other issues (find the leak, one decal came off for example), so my task list for the coming weeks is set - and that was what the testing was for! Thanks for your attention - this phase of fine tuning subs is always time consuming (and fun), and I’m very happy with the overall look of O-13!

Decals mounted and covered with a few layers of varnish…..

The cranes have been completed, the main cables are 0,3mm stainless steel which hopefully stays nicely straight over time. In the background the same cranes as I built them from wood twelve years ago on my K-XVIII model (after sailing 78times these still look good!). Also the wooden deck has been constructed from 1x1 mm wood bought at a rare model shop. A bit thick at this scale, but I don’t think I can sand it down nicely enough, so I’ll leave as is. For the moment covered by two layers of clearcoat, will add some more once the decals are mounted.

Today was a soldering day, I made the parts for the two cranes on deck. These were used to load torpedos and are permanent on deck. The drawing showed the main beams to be made of H-beams (for strength of course), and these were made at 3x3mm, seated in a 5mm brass tube that will anchor the crane in the deck. The torpedos weigh several tons, and the 14mm cable was rated for 11 tons. At 1:50 that was made from a 0,3mm brass wire. The double cabledrum was turned from 8mm brass and aluminium (brass was easier) and two blocks with 4mm wheels were made for each crane. Here is first loose assembly before painting and including the two actual cables (one for raising the crane and one for raising the torpedo).

My model boat club organised a beginner airbrush course in February. I bought a starmax about 10 years ago but kept using brush mostly. For this boat I’ve been practicing… The sail was already painted with rattlecan , but I used the airbrush for primer and grey coats of the hull. Some of the horizontal deck plates are very visible on photos, so I tried to mimick those by marking them with tape and applying some paint with a brush about 4 mm above the tape. Then tape was removed and after another couple of airbrushed layers the plate was nicely visible. I also tried some rows 3Dprinted rivets (0,2mm on decal) on a testplate, but after airbrushing they were no longer visible. Photos do show rivets but I need some more testing to see if I can make them visible (and hide the decal film). dis make a stencil for the flood holes, that worked OK but needed some touchup.

Super detailed work and great photography!