Sunday Morning Showdown: Sinn T50 Titanium Vs. Seiko Prospex Marinemaster SLA081
Another Sunday, another showdown! This week, we’re matching up two professional titanium dive watches that come in under €5K. The first is the recently introduced Seiko Prospex Marinemaster SLA081. This new version of the popular Marinemaster was released to celebrate 60 years of Seiko dive watches. The second is the Sinn T50, which debuted in 2023. It was part of a trio that also featured the brilliant two-tone titanium and Goldbronze T50. For this match-up, however, we picked the full-titanium version. It’s time to find out which of these two will claim the victory this week!
Today’s battle is one between two very capable, professional-level dive watches. The new Seiko Prospex SLA081 (€4,900) combines the looks of the original Marinemaster with a monobloc case, an updated bracelet, and a special 60th-anniversary dial. The Sinn T50 (€3,340) features the brand’s typical style in combination with a list of impressive specs. While there are some significant differences in size, these watches’ capabilities make them both worthy of a spot in today’s battle. Let’s find out which of the two will triumph!
Last week, on Sunday Morning Showdown…
But before we do, let’s take a quick look at the results of last week’s battle. In it, the Baltic Aquascaphe Dual-Crown won with the smallest possible margin, having taken 51% of the votes, and left the Mido Multifort 8 Two Crowns with 49%. The comments showed a stronger preference for the Baltic in this “Game of Crowns.” In the end, though, the numbers don’t lie. While the French still conquered the Swiss, it was by the skin of their teeth. Let’s see how things will turn out this week. Over to Jorg and Mike to make their cases.
Jorg: Seiko Prospex Marinemaster SLA081
At first glance, the new Seiko Marinemaster intimidated me a bit. Let’s get one thing straight: this is a big boy with its 45.4mm × 16mm case, which makes it substantially bigger than its adversary today. I know that will be a deciding factor in this showdown for some people, and I understand and respect that. The one thing I will say is that the difference in size does not translate into a huge difference in weight. Because both watches are made from lightweight titanium, their presence is not defined by their weight. This is what also immediately changed my perception of the SLA081.
Upon picking the watch up, any reservations about its wearability disappear. Granted, one must be able to pull off a watch of this size, but on my wrist, it wears like a charm. And I must admit that I was super impressed by this new Marinemaster. Over the past 12–18 months, we have seen that name pop up on a series of new models. From the new designs inspired by the 62MAS that Thomas and Daan reported on to the SLA079 and 081 that take after the 1968 Diver, they are all officially Marinemasters. But if we’re talking about the Marinemaster, most of us are referring to Seiko’s SBDX001, which gloriously won our Seiko World Cup.
The SLA081 features monobloc construction
I also love that specific Marinemaster model and its successors the most. This new SLA081 is the modern version of that watch, but Seiko went to great lengths to give it impressive improvements. First, the watch features a monobloc titanium case that is water resistant to 600 meters. To be more precise, it is a monobloc case with an L-shaped gasket to prevent helium infiltration, eliminating the need for an escape valve and making this watch suitable for saturation diving. The construction is a respectful nod to Seiko’s 6159-7000, which the brand refers to as its 1968 Diver, as well as its first-generation professional “Tuna” divers from 1975.
Paired with the case is a dark blue gradient dial featuring a beautiful wave pattern. This impressed me when I first saw it because the shade of blue is so nice. It adds depth to the watch over a standard black dial, and I prefer that instantly. The large luminous indexes and thick central hands give the dial that typical Marinemaster character that so many of us love. Surrounding the dial is a titanium bezel with a black DLC-coated stainless steel insert. Who said that black and blue don’t make a good combination? To me, this watch gloriously proves them wrong.
Charming looks over a clinical presence
And that’s also where the Seiko easily beats the full-titanium Sinn T50 for me. This Seiko speaks to me more because it has a historical story and a functional purpose while being more aesthetically charming. The Sinn T50 is colder and more clinical, which the two-tone version in titanium and Goldbronze solves beautifully. That’s also why that would be my Sinn T50 of choice rather than Mike’s pick in this battle. Put that two-tone version on a light gray silicone strap, and it will bring an enormous smile to my face. With the full titanium model, not so much. Don’t get me wrong; I like it, but I just can’t love it.
When I put the Seiko SLA081 on my wrist, I was surprised by how much I loved it. It shows clear references to the SBDX001 and follow-up SBDX017, and I loved that. I initially had my doubts about the black “bumpers” between the case and the bracelet. But they are there for a very practical reason. These two black DLC-coated stainless steel parts affix the bezel and keep it in place.
These bumpers are mounted on the case back and make servicing the watch with its monobloc case a lot easier. It was a great reminder of the purposeful development of this watch, which only deserves respect. The newly developed bracelet finishes the look. It has rounder links than previous versions and features a re-engineered clasp with a dive extension and an extra fold-over lock.
The new Seiko 8L45
Another reason I prefer the Seiko over the Sinn is the new 8L45 movement inside. Most of you are aware that previous versions of the Marinemaster used the Seiko 8L35, which is based on Grand Seiko’s 9S55 caliber. This new 8L45 is an updated version of the previous movement. It ups the power reserve to 72 hours and has an official accuracy of +10/-5 seconds per day. But we all know that, especially with higher-end Seiko models like this one, the accuracy is substantially better in real life.
Overall, I prefer this Seiko over the Sinn T50 for several reasons. To start, I would not choose the full-titanium Sinn T50 because the brand has a better option available in the two-tone model. But that is only the beginning of the story. More importantly, I love the historical background and look of the Seiko. Additionally, the modern structural updates combine a respectful nod to the past while improving the overall functionality of the watch.
The new movement is also a welcome update with better overall specs compared to the previous caliber. Lastly, wearing the watch was simply a lot of fun. Despite my initial doubts about the watch’s size, this Propsex Marinemaster SLA081 put a huge smile on my face, and that smile means so much more than any set of favorable specs. It makes this choice an easy one!
Mike: Sinn T50 Titanium
When Jorg and I meet for a Sunday Morning Showdown, we chat before writing the article. We decide who will support which watch and ensure the battle is fair. This week, we chose the Seiko SLA081 to compete against the Sinn T50 in titanium. At first glance, the price difference between the two may make it sound like an unfair fight, but it’s not a major factor in my argument. Besides, both are depth rated to at least 500 meters, mechanical, and made of titanium, so let’s see how they do.
A tough but clear choice
I’m a Seiko nut, and I do like the idea of the SLA081. Unfortunately, the 45.4mm by 50mm watch is too darn big for me. Despite the titanium construction, fantastic movement, and improved bracelet, I’d struggle to wear it. Plus, and this is my final complaint before moving on to the Sinn, the design is too similar to previous MM300 models. I’d like Seiko to move forward with new designs. The Sinn T50, on the other hand, does a nice job of evolving a prior design while bringing greater wearability to the party.
A great design
The T50 debuted in 2023, and I was fortunate to cover the press release. These watches are a follow-up to the relatively unpopular T1 and T2 models that I happen to love. Still, there’s no doubt that the T50 models are better designed and more mature. Whereas the T1 and T2 pieces were basically specialist divers, these pieces are made for utility and everyday wear. The case shape is inoffensive but pleasing and nicely finished. Plus, with a dimensional stat line that reads 41mm by 47mm by 12.3mm, the T50 don’t require custom shirts when trying to conceal it under a cuff.
A clear, no-nonsense dial
With Sinn, a straightforward, almost clinical dial design is virtually guaranteed. The Sinn T50 makes good on this with printed luminous hour and minute markers. The large luminous hands may lack the jewelry effect of the Seiko SLA081, but they’re seriously purposeful and light up like the sky on the 4th of July. Additionally, the push-and-turn bezel looks clean and has a large, luminous pip at the top.
A decent bracelet with flaws
Sinn’s bracelet design has been around for years. It’s nice enough on the wrist, but the clasp and wetsuit extension are old school and often come loose after enough use. It’s probably the one area where, finally, Seiko has an advantage. However, Sinn offers some sublime silicone strap options that wear beautifully. Also, the T50 is an easy watch to pair with just about any type of strap.
Using a Sellita instead of an in-house movement
Movement snobs will decry the use of a Sellita in the T50 and may prefer the 8L45 in the Seiko. I won’t be able to convince anyone dead set on an in-house caliber. However, the Sellita SW300-1 is a reliable choice and fits the use case. While its specs are nothing special, it’s easy to service and helps keep the price down to a reasonable level. Besides, when a watch has a moisture indicator on the side, the watch is more about remaining functional than showing off with a whiz-bang movement.
Overall thoughts on the Sinn T50
I can’t sit here and tell you that the SLA081 is a bad watch. It’s not, but I like the Sinn better. The design, the fit, and the mission-focused design execution all appeal to me more than the Seiko. The Marinemaster is simply too big to wear daily and feels like overkill. The cost savings of roughly €1,500 (the T50 retails for €3,340 on the bracelet) are just a bonus. In the end, though, you need to choose and let us know which watch you’d take home, to the sea, and everywhere else. Cast your vote, and let us know why you made the choice you did.
