Featured inventory photo: Blancpain Tribute to Fifty Fathoms “No Radiations” 5015B-1130-52 from Pucks & Timepieces. This photo illustrates the Fifty Fathoms family; movement specifications in this guide should be checked against the exact reference you are considering.
When comparing Blancpain calibre 1315 vs 1151, start with the watch you want to wear, not the larger number on the specification sheet. Both are automatic movements with substantial published power reserves: 120 hours for the 1315 and 100 hours for the 1151, according to Blancpain’s 1315 specifications and 1151 specifications.
My recommendation is to treat the movement as one part of a complete buying decision. Fit, condition, service documentation and the exact reference deserve at least as much attention as an extra day of running time.
Blancpain calibre 1315 vs 1151 at a glance
The figures below describe the movements as currently documented by Blancpain, not the total dimensions of the watches surrounding them. When buying an older example, verify its original specification rather than assuming that every current technical detail applies.
- Calibre 1315: Automatic winding, 120-hour power reserve, 4 Hz frequency and 5.65 mm movement thickness (Blancpain).
- Calibre 1151: Automatic winding, 100-hour power reserve, 3 Hz frequency and 3.25 mm movement thickness (Blancpain).
- Current balance-spring specification: Blancpain lists silicon balance springs for both calibres on its 1315 page and 1151 page.
What makes the 1315 interesting?
Blancpain describes the 1315 used in its three-hand Bathyscaphe as having three series-coupled barrels, a five-day power reserve and a stop-seconds function for setting the time precisely (Blancpain’s Bathyscaphe technical overview). Those are useful details to understand, but they should support your choice rather than make it for you.
If you rotate between several watches, consider how long each usually sits unworn. A generous reserve is most useful when it matches your actual routine; it is less important if you enjoy winding and resetting a watch before putting it on.
For the broader design and collection context, read our Fifty Fathoms guide. Use that alongside the movement specifications rather than choosing from either in isolation.
Why the 1151 deserves its own consideration
The 1151’s published movement thickness is 3.25 mm, compared with 5.65 mm for the 1315 (Blancpain 1151; Blancpain 1315). That difference is worth noticing, but it is not a substitute for checking the finished watch’s case height, diameter and profile.
I would not dismiss a watch because it has the 1151 instead of the 1315. If its proportions suit your wrist and its condition checks out, a shorter specification sheet does not make it the wrong watch.
How to compare two pre-owned examples
Before deciding between listings, ask for information that lets you evaluate the actual pieces. Avoid paying for a theoretical advantage that the seller has not documented.
- Exact reference: Request the full model reference and confirm which calibre belongs in that configuration.
- Service evidence: Ask for the service date, provider and work performed. Treat “recently serviced” as a claim to document, not a complete answer.
- Operating checks: Request a clear explanation of how winding, setting and any date function were checked. If reserve or timing performance is material to your decision, ask for a documented test.
- Wrist fit: Compare full case dimensions and side-profile photographs. Do not infer total watch thickness from movement thickness.
- Ownership costs: Get a model-specific service estimate if the history is uncertain, then include it in your budget.
Our pre-owned Blancpain buying guide provides a broader framework. For this decision, I would put a well-documented example that fits properly ahead of a more impressive calibre number in a questionable watch.
Frequently asked questions
Which movement has the longer power reserve?
Blancpain lists 120 hours for the 1315 and 100 hours for the 1151 (1315 specifications; 1151 specifications). Use those as manufacturer specifications, not a guarantee of the measured performance of an individual pre-owned watch.
Should I automatically choose the higher-frequency movement?
No. I would make the decision on the complete watch, with documented condition, fit and service requirements taking priority over a single movement specification.
What should I send when asking for sourcing help?
Send your preferred reference or collection, wrist size, budget and any must-have features. Include whether you prioritize a slim profile, a particular dial or convenience when rotating watches.
Find the right Blancpain for your collection
You do not need to become a movement specialist before choosing your next watch. Start a Blancpain sourcing request with Pucks & Timepieces, and tell me what you want the watch to do for your collection.
