Seiko Tuna is the brand name for a line of watches that are designed specifically for professional use and scuba diving. In particular, Seiko made these watches with the concept of saturation diving or deeper diving in mind. The watches of the seiko tuna range are characterized by protective screwed-on shrouds which have earned them the nickname of "Tuna".

Many firsts are part of the Seiko Tuna range. It is the first to include a ceramic-coated titanium shroud and a titanium monocoque box. Additionally, it comes with an L-shaped gasket and a rubber strap that is vented. Seiko Tuna watches Seiko Tuna watches are designed for practicality and can be employed as professional divers' instruments at great depths.

The Story Of The Seiko Tuna

In 1975, the first seiko tuna watch was created in response to a request that the company received in the year 1968. A saturation diver from Kure City in the Hiroshima prefecture of Japan had sent a complaint regarding Seiko divers watches that the company had been making since the year 1965. The pre-Seiko Tuna models weren't not durable to impacts and were not able to stand up to deep underwater pressure for prolonged periods.

Diver watches have to endure extreme conditions. Professional divers breathe in helium mixed with oxygen at extremely deep depths, where helium is easily absorbed by a watch's rubber seals. Divers undergo the necessary decompression. The watch's rubber seals let out helium via specially designed escape valves. Without these escape valves, the watch could fail to function properly. You can buy seiko tuna for sale.

Specifications and details

Movements

The Seiko Tuna can be divided into four movements: 6159B and 7549A, 5M23A and 7C46. Each of them was created by Seiko in-house.

The 6159B operation that runs the Grandfather Tuna and the 7549A movement of the first Golden Tuna were both developed by the company's Suwa division.

6159B was the movement derived from the 61xx movement which was used by Grand Seiko. It was exclusively used in professional Seiko dive watches, and never used in any other Seiko models.

While it's not clear who made the 7C46 or 5M23A movements to the reissued Golden Tuna or the Baby Tuna, it is likely Suwa.

The 6159B movement contains the most practical jewels of the entire range at 25 jewels. On the other hand the movement 7549A has the fewest at five jewels. The 7C46 and 5M23A are close with seven and six jewels, respectively. All watches in this range can be hand-wound. They usually cost 36,000 BPH.

DIALS

Black dials as well as LumiBrite luminescence are the hallmarks of the seiko tuna mod collection. These watches also have markers that indicate the hours, instead of numbers. An upside-down triangle signifies the 12-o'clock point, whereas round dots or circles mark all other hours.

Seiko Tuna watches all have the word "Seiko", along with an indication of depth range on their dials. When Seiko released its first Tuna watch, 6159-7010 the dial showed the depth range as "600" instead of "600m." Some people believe that this was an error however, since the later models of 1975, 6159-7010 and 6159-7019 models show "600m." Some believe that the watches with "600" instead of "600m" continued to be used until 1975.

BEZEL

The bezel that rotates uniformly that is present on all watches of the Seiko Tuna Series features a unidirectional rotating. The bezel is used to show divers how many minutes they've spent underwater. One click means one rotation and every rotation is in half a minute. To spin the bezel, there are two points of entry on the shroud. Once the bezel is set, divers must look at the time that the hand points to determine the elapsed time.