KNM Uller (Gulen, Norway — 185 fsw)

Intro

The KNM Uller was the last wreck I dove during my trip to Gulen, Norway and it was on the top of my list to dive. During my research before the trip, I had seen pictures of the massive cannon and the mines at the bow of the Uller and thought that it would make a great target for a photogrammetry model.

It is a bit challenging to find the wreck and I only had one dive on her with limited bottom time due to the depth but I was up for the challenge to build a model. I did end up finding and diving the wreck (1 of the 3 divers that day didn’t find it) and getting the photos to build a pretty good model.

This post will cover the history of the Uller along with photos and a photogrammetry model.

KNM Uller

The Uller was only recently found in 2009 after a number of failed attempts.

She was originally a Norwegian Vale-calss Rendel (flat-iron) gunboat built in 1876 and launched on 21 July 1876. Rendel gunboats were characterized by small size (Uller is 90 feet / 27m long), a low waterline, and also had a single, large gun which was aimed by maneuvering the boat.

Below is an example of a Vale-class gunboat (it is the smaller boat in the foreground with four people standing at the bow). Note how small it is compared to the people on the deck.

Shortly before World War I, five of these gunboats, including the Uller, were converted to minelayers.

During the refit, the heavy muzzle-loading gun was replaced with a 12cm breech loading gun. Because of the extra space they were capable of carrying a large complement of mines. I have read somewhere that they carried up to 50 mines.

When the Germans attacked Norway in April 1940 during World War II, the Uller was captured. At the time she was captured, she was in the process of mining the sea lanes to protect Bergen from the Germans and was taken by surprise when the Germans attacked.

The Germans used the Uller and her sister ship Tyr to mine the entrance to the Sognefjorden, which was still held by the Norweigans. On May 1st, 1940, the Royal Norwegian Navy bombed the Uller and then later that day it was bombed again by a Heinkel He 115 which scored a hit with a bomb on the port side stern of the ship. Funnily enough, the Heinkel was a German built seaplane. I have heard that this was the only time a Heinkel seaplane bombed and sank a ship.

I read on Wikpedia that the Tyr scuttled the Uller but Ørjan disputes that and I’d trust his version of history. According to Ørjan, the Uller was bombed as she was near the reef (and they possibly beached her?) and the sailors went onboard the Tyr. The locals took whatever they wanted from the beached wreck. A short while later, a big storm lifted the Uller off the reef and she sank and went down the slope.

The Wreck

The wreck is close to the Ferndale/Parat wreck. Note that it is directly in the path of a major ferry and we saw ferriesthroughout our time there. It is important that divers are comfortable using a SMB before they surface. The ferries know that the Vikingfjord is a dive vessel and that divers can be in the water, but it is always good practice to send up a SMB.

There is not a permanent buoy on the wreck. Instead, they drop you at a pole sticking out of the water with a green panel on it. I suspect it is some kind of tide monitoring system. You then sight in the edge of the cliff as shown below, take a bearing and quickly descend to get out of the surface current. By my compass, it was almost exactly due West.

There is a gulley structure underwater with a wide plain of sand. Underwater, there is a ridge line that is pretty prominent on the left and a smaller, sloping ridge line to the right — both of which form the gulley or valley in which the wreck sits. If you delay on the surface and drift a bit, you will probably end up in the wrong gulley. Follow the gulley down and keep to the left where you will find the wreck “close-ish” to the left ridge (as you proceed west). The wreck faces downhill with the stern at about 150 fsw and the bow about 185 fsw deep.

Prominent features of the wreck include the dual props and large rudder on the stern, the big cannon in the bow and a few mines up in the bow. There are also some mines on the seabed floor. According to Ørjan, a relative of his is in the Norwegian Navy and sent some divers down to ensure that the mines are not armed and they aren’t. However, I wouldn’t disturb them. 🙂 There is also an obvious explosion blowout in the starboard stern area.

Below is a diagram from the briefing that Ørjan provided prior to the dive.

Photos

Below are a selection of photos that were taken during the photogrammetry process. Note that these are not take for composition, etc. but instead to build a model so they aren’t the best photos but they can indicate key points on the wreck.

Photogrammetry Model

The model was a bit tougher than I expected. The complicating factors were the need to go into the explosion area (I was expecting mainly flat hull areas) which required more time & photos. Also, the open deck was a bit hard with the slats though it and the sharp edges at the outside edges of the vessel.

In all, I took 1,341 photos and I was running close to my stated runtime so I had to start heading back up the slope to do my deco. I wish I would have had another 10 minutes of bottom time to fill in a few areas. Given that I had never seen the wreck before, the depth, and the dark conditions, I’m pretty happy with the results. Below are some screenshots from the model:

I’ve also uploaded the full photogrammetry model to Sketchfab and provided the links below.

Low Res / Mobile Version

High Res / Desktop Version

References

Wikipedia – Uller

Wikipedia – Henkel 115

Gulen Dive Resort – KNM Uller

Verbal dive briefing from Orjan