How to Choose the Right Aquaculture Anchor – Sand Plough vs Stingray Anchor

SMEOCEAN supplies aquaculture mooring anchors and complete anchoring systems to fish farms across Europe and South America. Our manufacturing facilities have been producing mooring equipment for the aquaculture industry for over 20 years. The following guide is based on real project experience and customer feedback from salmon farms in Norway, Chile, and beyond.” 

We have previously covered anchor chain selection and mooring failure risks. Now we address a more specific question: which anchor type should you choose for your fish farm mooring system? 

Anchor selection comes down to three factors: seabed conditions, environmental loads, and redundancy requirements.  

What Does "Exposed" and "Sheltered" Mean for Aquaculture Sites? 

Exposed sites are open sea areas with no islands or landmass to block wind and waves. Sheltered sites are located near islands, coastlines, or natural formations that reduce wave energy. 

This distinction directly affects aquaculture anchor selection: 

- Sheltered sites: lower wave energy, lower mooring requirements

- Exposed sites: higher wave energy, requires stronger anchors and more mooring lines 

1. Single Shank vs Dual Shank – What’s the Difference? 

Both are drag embedment anchors that rely on horizontal tension to penetrate the seabed. 

Single Shank Anchor – one arm connecting the fluke to the mooring attachment point. Plough anchors (such as Sand Plough) fall into this category. 

- Advantages: wide size range, readily available, cost-effective, recoverable

- Limitations: poor performance under vertical loads, less stable in hard or layered seabeds

- Holding power: approximately 20-50 times its own weight, depending on seabed conditions

Dual Shank Anchor (Stingray-type) – two arms sharing the load between them. Designed for high holding efficiency with a lightweight, foldable structure. 

- Advantages: better load distribution, built-in redundancy, significantly higher holding capacity

- Limitations: higher cost, more complex installation

- Holding power: over 40 times its own weight, and in some configurations up to 3 times the holding power of conventional anchors

Key comparison – same weight, different holding power: 

In sand seabed, a 1,000kg dual shank anchor provides approximately 40tons of holding power. A single shank plough anchor of the same weight typically provides around half that – roughly 20 tons. This means dual shank anchors deliver approximately 2x the holding power of single shank anchors at the same weight.  

2. How to Choose – A Decision Framework 

Step 1 – Assess seabed conditions.

Sand and mud are ideal for drag embedment anchors. For rocky seabeds, consider deadweight anchors or anchor piles.

Step 2 – Evaluate site exposure. 

| Site Condition |  Recommended Anchor Type |

| Sheltered site, small to medium farm | Single shank anchor |

| Exposed site, large farm | Dual shank anchor |

| Feed barge or critical infrastructure | Dual shank anchor |

| Temporary or seasonal farm | Single shank anchor |

Not sure which category your site falls into? Send us the farm location – we can assess local wave and current data and provide a specific recommendation.  

3. Transport Cost Is the Real Difference 

Here's the translation of that section: The Real Cost Difference Is in Shipping 

Whether single shank or dual shank, manufacturers charge by weight. The real cost difference is not in the unit price – it's in the freight.

Traditional welded anchors are one-piece and bulky, which wastes container space. Take a 40HQ container to Europe as an example: it only holds 6 units of 1.7-ton welded Sand Plough anchors. But the modular design – which allows disassembly and stacking – fits 14 units in the same container. That's more than double the quantity. When freight is spread across each anchor, the landed cost drops by roughly 30%.

Last year, we supplied a 1.2-ton dual shank anchor to a salmon farm in Italy. We modified the anchor into a modular design without compromising holding capacity, and supplied all bolts and hardware for easy on-site assembly. After receiving the shipment, the customer calculated the actual cost savings – the freight saved exceeded the price difference of the anchor itself. They were very satisfied. 

Let me know if you need any adjustments. 

4. Single Shank vs Dual Shank – What We Recommend 

Anchor choice is a trade-off between cost and safety margin. For exposed aquaculture sites, the extra cost of a dual shank anchor buys: 

- 2x the holding power at the same weight

- Better load distribution and structural redundancy

- Critical for insurance compliance and escape prevention

Saving money on the anchor rarely pays off when measured against a single escape in you are still unsure – send us the farm location, water depth, and cage count. We have supplied similar sites across Europe and South America and can recommend the most cost-effective anchor solution for your specific conditions.

More Links:

How to Choose Mooring Plate for Aquaculture?

How to Choose the Right Anchor Chain for Deep-Sea Fish Farms – A Procurement Guide

Deep-Sea Aquaculture Anchoring Solutions