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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsThe Borealis Portus Cale was a well-equipped automatic dive watch reviewed in 2017 and 2018, with a reported 300 m water-resistance rating, Miyota 9015 movement, sapphire crystal and 120-click unidirectional bezel. Contemporary reviews listed it at $320 USD, but that is a historical price—not a current offer. Current Portus Cale availability and pricing were not confirmed.
What the Borealis Portus Cale was
The Portus Cale was a Borealis mechanical diver covered by Fratello Watches on March 29, 2018, and The Time Bum on December 19, 2017. Fratello identified its reviewed sample as a prototype; The Time Bum said the author tested two prototypes. Their observations and specifications therefore describe the examples reviewed and should not be read as a guarantee that every production version had identical details.
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The model’s appeal was its combination of conventional dive-watch equipment and a $320 historical price reported by both publications. That was the reviewers’ 2017–2018 value framing; it does not establish what the watch would cost or how it compares with alternatives today.
Portus Cale specifications reported by contemporary reviews
| Specification | What the reviews reported |
|---|---|
| Case | 41.5 mm stainless steel; Fratello reported a 48 mm lug-to-lug measurement and 22 mm lug width. The Time Bum also reported 41.5 mm by 48 mm. |
| Thickness | Just over 11 mm, according to The Time Bum’s December 19, 2017 review; Fratello did not state a thickness. |
| Movement | Miyota 9015 automatic. Fratello reported 28,800 beats per hour, 24 jewels, hacking and a 42-hour power reserve. |
| Date options | Date and no-date versions were reported by Fratello. |
| Crystal | Sapphire with anti-reflective treatment or properties, as described by both reviews. |
| Bezel | 120-click unidirectional bezel. Fratello described it as PVD-coated. |
| Crown and case back | Fratello reported a screw-down crown. The Time Bum described both a screw-down crown and case back. |
| Water resistance | 300 m, as reported by both reviews. These are reported specifications, not evidence of independent laboratory testing. |
| Bracelet | Fratello described screw-adjustable links and a micro-adjustable clasp. The reviewer called the clasp stamped and functional and noted there was no wetsuit extension. |
| Dial and lume variants | Fratello listed blue, black and white dials. The Time Bum described multiple dial and lume variants; the reviews do not establish one universal combination. |
How the size may wear
At 41.5 mm across with a reported 48 mm lug-to-lug span, the Portus Cale had a relatively long footprint for its diameter. The Time Bum called it slim for a diver and found it comfortable on the author’s 6.5-inch wrist. That is one reviewer’s experience with prototypes, not a fit guarantee: wrist shape, bracelet sizing and personal preference all matter. Fratello likewise described its bracelet sample as not uncomfortable, while noting that it was not a lightweight watch.
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The 22 mm lug width gives a clear starting point if considering a replacement strap, but confirm the fit of a specific strap and its spring bars before buying.
Movement and diver features
The Miyota 9015 is the named automatic movement in both reviews. Fratello’s listed figures—28,800 beats per hour, 24 jewels and 42 hours of power reserve—are the publication’s reported specifications. The same review says the movement hacked, meaning the seconds hand could be stopped for setting, and that buyers could choose a date or no-date version.
The sapphire crystal, screw-down crown and 120-click unidirectional bezel are conventional practical elements for a diver, while the stated 300 m rating is substantial on paper. A rating alone does not establish how an individual watch performs after years of use, nor does it substitute for checking the condition and seals of a used example. No independent water-resistance test is documented in the reviews.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the reviewers liked—and what they qualified
Fratello’s observations
Michael Stockton praised the specification set but noted cost-conscious case finishing in places, a functional stamped clasp and the absence of a wetsuit extension. He also mentioned that the unscrewed crown felt somewhat wobbly. Stockton explicitly said he did not test the movement’s timekeeping, so his review should not be treated as a timing-performance assessment.
The Time Bum’s observations
Loren Sciurba praised the prototypes’ lume, bezel action, bracelet and versatility, and described the watch as comfortable on a 6.5-inch wrist. These are personal impressions from two prototypes rather than controlled or independently replicated results.
Historical price and present-day availability
Fratello and The Time Bum each reported a $320 USD price in their 2018 and 2017 coverage, respectively. Fratello noted that shipping and VAT depended on the buyer’s location. The Time Bum described a $160 deposit, with the balance due before shipping. These details document the historical offer, not a current retail price.
The Time Bum also cited a 2018 sold secondary-market listing advertising a new-in-box example for $335. That single historical listing is not a current valuation or evidence of today’s market price.
Current Portus Cale stock and an official current price were not confirmed. Borealis’s current product page located for this coverage is for the distinct Porto Covo, not the Portus Cale. Its specifications must not be used to update the older model: the page lists a 40 mm case, 42.5 mm lug-to-lug, 12.3 mm thickness, PT5000 or Sellita SW200 movement options and 300 m water resistance, and displayed preorder messaging when checked. See the Borealis Watch Company product page.
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- Confirm the model: Check that the listing is for the Portus Cale, not the Porto Covo; their sizes and movement options differ.
- Verify the exact configuration: Ask whether the watch is date or no-date and confirm the dial, lume and bezel details rather than assuming all variants match.
- Inspect condition and completeness: For a used watch, review the crown, bezel, crystal, bracelet, clasp and any service or water-resistance documentation. The published 300 m rating does not establish present-day water resistance.
- Judge price against current evidence: Treat $320 and the $335 2018 listing as historical reference points only. They do not establish a fair current asking price.
Verdict
The Portus Cale’s historical proposition was compelling on paper: a Miyota 9015, sapphire, 300 m reported water resistance and a unidirectional bezel at a contemporary reported price of $320. The reviews also record meaningful trade-offs, including cost-conscious finishing, a basic stamped clasp without wetsuit extension, and the lack of a timekeeping test in Fratello’s account. It is best understood as a promising historical microbrand diver, not as a watch with confirmed current availability, current value or independently verified performance.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
