Benchmade Undercurrent 18040S Fishing Knife with Sheepsfoot Blade
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Why buy from Amazon?
Amazon has a documented Prime delivery program that covers millions of items, and that is the most concrete order-related support behind buying here.
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Some customers report slower replies or needing more follow-up than expected when they asked for help after ordering. If an order needs post-purchase support, that part of the experience is not always smooth.
Some customers also report delivery problems after ordering. That keeps follow-up and delivery as the areas to watch if you place the order here.
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Why buy from Cabela's?
Cabela's ships orders from the US, and there is a documented return process for most purchases if something needs to go back.
The return route includes exchange and refund options, so there is a clear way to correct an order that is not right.
Worth knowing
Some buyers report slower replies or more follow-up than expected when they needed help after ordering. Allow a little extra time if you have a question about an order.
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Why buy from Scheels?
Order from Scheels for the customer service. Buyers describe staff as friendly and helpful, and that is the part of an online gear purchase that matters most when something needs attention.
What buyers say
Several buyers describe customer service as friendly and helpful. The praise is about the service itself rather than a specific product or issue.
Worth knowing
The friction shows up after ordering. Some customers report slower replies or extra follow-up when they needed help, including order-status or cancellation problems that took more chasing than expected.
If you need help after an order, plan for a little extra persistence rather than expecting one contact to close it.
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Quick Facts About Benchmade Undercurrent 18040S Fishing Knife with Sheepsfoot Blade
- A fixed-blade dive knife built for cutting lines, ropes, and bait at the surface or underwater.
- The sheepsfoot blade with partial serrations handles tough cordage without the risk of an accidental point.
- CPM-MagnaCut steel holds an edge well and resists corrosion in saltwater conditions.
- The Santoprene handle, a vulcanized EPDM rubber and thermoplastic composite, stays grippy even with wet or gloved hands.
- At 5.38 oz and 9.43 inches overall, it is substantial enough to work with but not cumbersome to carry.
- Benchmade’s LifeSharp program covers free re-sharpening, cleaning, oiling, and adjustments for the life of the knife.
- A solid choice for recreational divers and water-sports enthusiasts who want a dependable, low-maintenance cutting tool.
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Benchmade Undercurrent 18040S: A Fixed-Blade Dive Knife Built for Serious Recreational Divers
The Benchmade Undercurrent is a fixed-blade fishing and diving knife with a 4.3-inch sheepsfoot blade made from CPM-MagnaCut stainless steel, partially serrated, and designed to cut line, rope, and bait reliably in wet conditions.
If you are a recreational diver who wants a capable, well-made blade you can trust underwater, this is worth a serious look.
The Blade: Why CPM-MagnaCut Steel Matters
Most dive knives use standard stainless steel because it resists corrosion reasonably well. Benchmade went a step further with CPM-MagnaCut, a premium powder-metallurgy steel that balances edge retention, toughness, and corrosion resistance better than conventional stainless grades.
In practice, this means the Undercurrent holds a sharp edge longer between sharpenings, and it is less prone to the pitting and rust that salt water accelerates on cheaper blades.
The sheepsfoot blade shape is the right choice for diving. A sheepsfoot has a straight cutting edge and a spine that curves down to meet it, with no sharp point. That blunt tip makes it far safer when you are cutting entangled line underwater, where visibility is low and one hand may already be occupied. You are not going to accidentally stab yourself or a buddy reaching for a tangle in kelp or a net.
The partial serrations run along a section of the edge, giving you a plain edge for bait work and clean cuts, and a serrated section for sawing through thicker rope or braided line that a plain edge would slide off. Both sections earn their place on a dive knife.
The Handle: Grip When It Counts
The handle is Santoprene, a vulcanized EPDM rubber and thermoplastic composite. Santoprene is molded, durable, and grippy even when your hands are wet and gloved. It does not absorb water or degrade with repeated saltwater exposure the way some softer rubber handles do.
The knife is ambidextrous, so left- and right-handed divers can use it without modification. Total weight is 5.38 ounces, and the overall length is 9.43 inches. That is a solid, substantial knife, not a lightweight backup blade.
The LifeSharp Guarantee
Benchmade includes their LifeSharp service with this knife. Send it back at any point and they will clean it, oil it, adjust it, and re-sharpen it to a factory edge, free of charge, for as long as you own it.
For a dive knife that gets regular saltwater exposure, this matters. Salt water accelerates corrosion and dulls edges faster than freshwater use. Knowing you can restore the blade to factory condition without cost removes one of the real maintenance headaches of owning a quality dive knife.
Care and Maintenance
Benchmade specifies hand wash only. After a dive, rinse the knife thoroughly in fresh water and dry it before storing. Do not run it through a dishwasher. CPM-MagnaCut is corrosion-resistant, not corrosion-proof, and good habits after every dive will keep the blade in the condition the steel is capable of.
What Comes in the Box
- Benchmade Undercurrent knife (model 18040S), Depth Blue Santoprene handle
No additional accessories are listed in the specifications. Confirm sheath or mounting options separately if that is part of your setup decision.
Who This Knife Is For, and Who It Is Not
The Undercurrent is built for recreational divers who want a serious, long-lasting blade and are willing to maintain it properly. The premium steel, the thoughtful blade geometry, and the lifetime sharpening service all point to a knife you buy once and keep for years.
If you are a brand-new diver who is not yet sure how often you will dive, or if you simply need a small backup blade to clip to a BCD strap, this may be more knife than your situation calls for. At 5.38 ounces and 9.43 inches overall, it is not a compact secondary cutter.
But if you dive regularly, you cut line or rope with real frequency, and you want a blade that rewards proper care with decades of reliable performance, the Benchmade Undercurrent is one of the more thoughtfully designed options available.
Specifications for Benchmade Undercurrent 18040S Fishing Knife with Sheepsfoot Blade
- Brand
- Benchmade
- Model
- Undercurrent
- Model Number
- 18040S
- Blade Style
- Sheepsfoot
- Blade Material
- CPM-MagnaCut Steel
- Edge Type
- Partial Serrations
- Handle Color
- Depth Blue
- Handle Material
- Santoprene
- Handle Composition
- Vulcanized EPDM Rubber and Thermoplastic
- Handle Type
- Molded Composite
- Knife Type
- Fishing Knife
- Primary Use
- Cutting Lines | Ropes | and Bait
- Maintenance
- Easy to Clean
- Grip
- Sure Grip in All Conditions
- LifeSharp Services
- Re-sharpening | Cleaning | Oiling | Adjustments
- Re-sharpening
- Free Factory Edge Re-sharpening for Life
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