Mooring Buoy Inspection, Repair & Installation
Sleep better knowing that your mooring system is up to the task. It's important to know that the components of your mooring system are in good shape and properly sized for environmental conditions and the length of your boat.
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When was the last time you had your mooring system inspected? It is recommended that you have your fresh water mooring system inspected at least every three years. |
Thankfully, corrosion (rust) of steel mooring chain is a very slow process in fresh water and can takes decades before it weakens the chain links to the point where replacement is required.
However, the constant motion caused by wind and waves create friction where the chain rubs against itself or on something hard like the anchor weight...which can eventually weaken the chain's strength. Excessive chain wear combined with the mechanical forces caused by the chain kinking when it wraps around the mooring anchor, can cause the chain to break... and is a leading cause of mooring system failure.
Fact: Although commonly used, large concrete blocks are not the best solution as anchors for mooring systems as the bottom chain (called a "rode") tends to wrap up around the block on the lake bottom, kinking the chain and shortening the rode, resulting in damage to the chain and increased shock loading on the vessel's tie off points (hardware).
Fact: Keep in mind that concrete weighs approximately 60 % of its surface weight underwater... so a thousand pound block of concrete actually only weighs around 600 pounds on the lake bottom.
Fact: Most existing mooring buoy systems are not built or installed to proven and accepted industry standards. Will your boat insurance cover boat damage or loss if your mooring fails?
Fact: Transport Canada (Canadian Coast Guard) have started a program of inspecting mooring buoys in British Columbia and are ticketing systems not Transport Canada compliant.
Our professional team will inspect and video your existing mooring system from the anchor to the float. You will get a confidential, written report as well as a video of what we find.
Call or text Bart today for a "no obligation" quote: 250-254-5076 or email kootenaydiving@protonmail.com
Call or text Bart today for a "no obligation" quote: 250-254-5076 or email kootenaydiving@protonmail.com
Mooring Buoy Installation
700 lb Inverted Pyramid Anchor in the cradle- Anchor holds 3200 lbs with 3:1 scope - tested to hold a 30 foot vessel in sustained hurricane force winds (64 knots -118.5 kilometres per hour)
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1700 lb "inverted pyramid anchor slung in the moon pool of the delivery barge. Tested to hold 7300 pounds with a 3:1 scope - a 50 foot vessel in sustained hurricane force winds
(64 knots - 118.5 km/hr.) |
Another pyramid anchor ready for permanent placement
Our heavy lift barge can accurately place mooring anchors - seen here recovering pumps
A mooring buoy system should be sized for the largest vessel that will be attached to it.
Mooring system design has been around for centuries... and yes...there is a correct way to do it.
Mooring anchor
Let's start with the correct anchor. Although heavy concrete blocks tend to be the "go to" anchor weight currently in use today, they really aren't well suited for the job.
Why a concrete block is a poor choice for a mooring buoy anchor.
As the wind blows the moored boat around the anchor, (called the "swing"), the heavy bottom chain starts wrapping up around the concrete block. As the bottom chain wraps around the concrete block it gets shorter and the pull from the moored boat becomes more vertical - which reduces the desired buffering effect and substantially decreases the holding power of the mooring system. As well, a wrapped chain reduces the life of the chain due to wear from friction and kinking.
Keep in mind that the damage to the chain wrapping around a mooring anchor is the primary cause of failure in a mooring system. The other causes are the improper sizing of the parts of the mooring system and using parts that are not suited for a mooring system.
What is a good choice for a mooring buoy anchor?
Research has shown that an inverted pyramid style anchor originally perfected by the Dor-Mor company is far superior in holding power - for it's weight - than any other weighted anchor. www.dor-mor.com The Dor-Mor design is basically an inverted pyramid that will settle into the soft lake bottom and provide up to ten times it's weight in holding power. In the unlikely event that it does pull loose, the design catches on the lake bottom and re-sets itself. On a hard, rocky bottom where the inverted pyramid cannot settle into the lake bottom, the chain will slide up and over the sloped sides of the anchor instead of wrapping around it.
We have partnered with Enviromarine Ltd - a local Canadian company - who custom manufacture inverted pyramid anchors utilizing a welded steel shell with a "schedule" 70, 1/2 inch hardened attachment chain, cast in the reinforced concrete core.
The "Rode" - Bottom Chain
Attached to the mooring anchor weight with a large swivel is a heavy chain (called a "rode"). The bottom chain is optimally one and a half to three times as long as the water is deep (this ratio is called the "scope"). So for a mooring in 9 metres (30 feet) of water depth, the rode should be 13.5 metres (45 feet) to 27.4 metres (90 feet long). A 3:1 scope is best if possible.
The heavy bottom chain that is the correct size and length, does two things.
- As the wind and waves push the vessel away from the mooring anchor weight, a portion of the bottom chain lifts in a gentle "catenary" curve which provides a gentle buffering effect on the moored vessel. If installed correctly, this will eliminate shock loading on your vessel's deck hardware.
- A properly sized bottom chain will insure that the pull on the anchor is lateral... across the lake bottom, which multiplies the holding power of the anchor... Up to 10 times when the scope is 3:1 while using an inverted pyramid mooring anchor.
The Riding Chain
The riding chain attaches with a swivel between the bottom chain and the mooring buoy. It is usually about half the size of the bottom chain with a length to match the maximum depth of the the mooring site.
Mooring Buoy
The mooring buoy itself is designed (and sized) to float the weight of the lighter riding chain that attaches the buoy to the bottom chain. Coast Guard /Transport Canada have specific designs for mooring buoys used in Canadian waters. In the last couple of years, enforcement has been initiated at the coast and more recently, inland lakes, where non-compliant buoys have been ticketed.
Location
It is important to site your mooring system so the scope doesn't put your vessel in danger of going aground in low water or infringes on your neighbour's waterfront. As well, an underwater inspection is necessary to make sure that there is nothing on the lake bottom in the swing area that will impede the free swing of the rode.
Getting a mooring system installed.
Although installing a mooring system may sound overwhelming, it really isn't. All it takes is a phone call to us at Kootenay Diving and we will provide you with a "no obligation" quote.
Call Bart at 250-254-5076 or email kootenaydiving@protonmail.com
No supply chain issues here...we have a good stock of buoys
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Our multi-purpose lifting barge can hoist up to 2000 pounds and can be put in at most boat launches.
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