Seiko Prospex Black "Slim Turtle" Watch Review (SPB317, SPB317J1)

Seiko loves Prospex reissues of dive watches from its back catalog. Reinterpretations of the 62MAS, Willard, and Marinemaster models have become quite popular. Seiko has reissued another lesser-known 60s dive watch, the 6105-8000. Seiko refers to it by reference number SPB317, but the community calls it the Slim Turtle.

Around the time this model was released, I purchased and reviewed the white dial version, SPB313. Shortly after, my friend bought the black dial SPB137 version. I recently borrowed that one from him for this review.

Seiko Prospex SPB317 First Impressions

Despite only color differences, the black dial version takes on a very different look. Besides the obvious dial change, darkened hands and markers are swapped out for bright silver ones. It makes the watch more versatile and subtle, yet still attractive and eye-catching.

Wearing the Seiko Prospex SPB317 Slim Turtle

As the nickname implies, the Slim Turtle shares a similar case shape to the "regular" SRP  Turtle, but with reduced dimensions. At 41mm, it is about 4mm narrower, and its 12.3mm thickness is about 2mm less than the full-size version.

Besides wearing MUCH smaller than the original Turtle, the Slim Turtle also wears smaller than its dimensions indicate. Compact lugs, and a small bezel help to facilitate this. It's a very comfortable and compact watch for a 200m diver, especially on a strap (more on that later).

The sides of the case are fairly slim, and a lot of the overall thickness of the watch is hidden in the bulge on the back side of the case, allowing it to be masked a bit by the wearer's wrist.

Seiko Prospex SPB317 Details

Seiko employs a number of other techniques to slim down and clean up the look of the Slim Turtle. A lack of a chapter ring means that the crystal and dial shrink down visually.

The lack of chamfers on the case, and the tightly integrated lugs also give it a cleaner, unified appearance. The unsigned crown is also deeply recessed in the case, which hides its size a bit (and provides protection).

The 317's dial uses Seiko's latest direction for its newer dive watches to meet updated ISO dive requirements. A lumed marker is required at every hour. The Slim Turtle and other models move the date completely out of the way and place it at 4:30. Some hate this, but I like how Seiko made the aperture as small as possible and also rotated the text to be oriented correctly. Because it's color-matched, it's a pretty clean way of doing it.

The 317's crystal has a very subtle dome, and even the highest point of the arc is still below the edge of the bezel. The result is a less dramatic distortion of the dial. Also of note, the crystal has an effective AR coating applied to the underside.

The 120-click action of the one on SPB317 will be familiar to owners of other Seiko divers. The rotation has nice friction, but the clicks are not particularly precise or distinct.

Beyond that, a coin edge makes the bezel easy to grip and also looks good. The insert is not as attractive to look at as the ceramic one on the King Turtle but works with the understated nature of this model. 

Like with 62MAS models, the silver hands are half brushed and half polished. This aids legibility in different light conditions.

It has fantastic Seiko green Lumibrite lume, which I find to be brighter than the blue on other models.

Seiko Prospex SPB317 Strap

While the white SPB313 or the black with gold indices SPB315 come with bracelets. The standard black dial SPB317 only comes with a silicone strap. I've mentioned before how Seiko's silicone straps are very soft and comfortable, but attract a lot of dust.

I also don't prefer metal keepers. They look great at first but tend to dig into my wrist and pick up scratches easily.

I've preferred wearing in our new Pro Diver Straps! Here is a list of some of the other straps that would fit and we think look great with this watch. At the end of the article you'll also find photos of some of our favorite combinations.
-Deployant Rubber
-Ribbed Rubber Pass-Through
-Ridge Rubber
-Tropical Rubber
-Premium Sailcloth and Sailcloth Colorway Collection
-Smooth Rubber
-Rubber and Sailcloth Hybrid Straps
-Vented Rubber
-Slim Ridge Rubber
-Waffle Rubber
-Beads of Rice Bracelets
-Epsom Leather
-Elastic
-Seatbelt

Most Seiko Prospex divers feature larger than standard lug holes and spring bars, which won't fit in standard straps. While all of our straps are compatible with these watches, many other straps aren't. Additionally, some people don't prefer the slight bit play it is present when installing one of our straps. That's where StrapHabit's Thin Spring Bars for Seiko Fat Lug Holes come in. These can be installed in some StrapHabit straps as well as most straps with standard spring bars and fit Seiko divers perfectly. They have 1.1mm tips, but are 1.8mm thick at the center.

Seiko Prospex SPB317  Movement

As with other SPB models, SPB317 uses Seikos caliber 6R35. Compared to the 4R series movements in less expensive models, Seiko adds a Spron hairspring and other upgrades, increasing power reserve from 40 to a very useful 70 hours and improving the accuracy.

Seiko uses 24 jewels in the 6R35. It beats at a slower 21,600vph and is listed as accurate to +25 to -15 seconds per day.

Conclusion

The Slim Turtle does lack some of the excitement of the other Seiko case shapes (possibly why Seiko has waited longer to reissue this design), but that will serve as a positive for a lot of collectors. Not everyone wants a chunky diver, and the Slim Turtle is a watch that can blend in a bit more. Choose this black dial model over the bright white and it will blend as a daily watch yet still feel special.

Specifications:

Name: Seiko Prospex Automatic Diver's Watch Re-Interpretation
Reference Number: SPB317J1
MSRP: $900
Diameter: 41mm
Height: 46.9mm
Thickness: 12.3mm
Lug Width: 20mm
Movement: Caliber 6R35
Power Reserve: 70 hours
Water Resistance: 200m
Crystal: Curved sapphire crystal with anti-reflective coating on the inner surface
Crown:  Screw-down
Bezel: Unidirectional, 120 clicks
Strap: Silicone

 

Shop Other Straps for the Seiko Prospex Automatic Diver "Slim Turtle":

Pro Diver Strap

Ridge FKM Rubber

Tropical FKM Rubber

Waffle FKM Rubber

Vented FKM Rubber

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