Frequently Asked Questions
I am getting some very good questions on both social media and the web page chat. Here I have done my best to answer them.
But isn't the cable is designed to be the weakest point? Don't you want the cable to break before the ramp or a post / winch stand? Won't it still be the weakest point?
Excellent question! The cables are your dock's lifelines. When a cable fails, the dock will then be free to move in the wind, gaining speed and increasing the impact load when it hits anything. Which will most likely one of the neighbor's docks you are surrounded by and which you will be liable for repairing. The walkway can be ripped from its mount on shore, which will be expensive to have repaired. The walkway to dock joint can be torn loose. A cable letting go is the last thing you want.
The cables are not the weak link. The smallest cable most use is the 5/16" with a minimum breaking strength of 8520 pounds and the more commonly used 3/8" cable is good for 12,200 pounds. Most docks use hand winches in the 2500 to 3500 pound working capacity. They have a minimum breaking strength of roughly twice that amount. The winch body will bend from the drum being yanked on until either the bolt passing through the drum fails or the teeth the locking pawl engage will no longer mesh with the teeth on the drum and release all the cable on the drum. The shore anchor is usually a post driven into the ground with some concrete around it. Most weigh less than a ton. If you want to get a tent peg out of the ground, you tap on its side with a hammer, then it comes out easy. Same thing happens over time with dock anchor poles. Dock moves a few inches in the wind, pulls the cable tight. Its kinetic energy becomes impact energy on the pole. Over time it gets loose. A storm passes through with a bigger wind that removes the pole from its hole. Your dock is then loose to sustain/cause damage.
A dampener on each cable mitigate the shock/impact load that occurs every time the dock moves. Dock springs are a form of dampener. Dock springs introduce time into the formula used to calculate shock and impact loading. See the "What is Shock Loading" page for a better explanation of how time is critical. Introducing time into each impact, slowing the loading of your components, is the only way to mitigate your dock's kinetic energy. There are currently only two forms of dampeners and springs are the better choice of the two. Other than a dock spring, an elastic connection from marine high density polyethylene rope is your other choice. Rope is fragile, degrades with UV exposure and time, is easily abraded and can be cut. Marine HDPE rope has a 10% yield factor which is both good and bad. A dock with a 65 foot walkway secured with rope has a distance of about 85 feet from the dock to the anchor pole and will stretch 8.5 feet when a load is applied. That is 17 feet your dock and move back and forth. Its just not rigid enough. A dock spring has 6 to 7 inches it can compress when arresting the movement of a dock.
What hours are you available?
I want to shoot for regular business hours, 9 am to 5 pm, but open 7 days a week. Call me if you need further info about dock springs or help selecting a dock spring set for your application.
The web site says the springs I want are not in stock. Can I back order them?
As I figure out the demand for dock springs, I will fill orders as they occur. The materials I need are pretty readily available so the longest it will take to fulfill a back ordered set would be less than 10 days. I keep about 24 sets in stock.
How do you figure which spring my dock would need?
I make 4 sizes.
The Light Duty Dock Spring has 600 lbs./in constant compression rate and a pair would serve a swim platform up to a single slip single story dock well.
The next size up is the Progressive Rate Dock Spring with a progressive spring rate that starts at 800 lbs./inch and ramps up to over 4000 lbs./inch as it is compressed. It will work fine for all docks as the resistance to compression increases with load.
The Heavy Duty Dock Spring has a 1800 lbs./in constant compression rate and would best serve a double decker, multiple slip dock, on a main body of water where it sees substantial exposure to wind, current, or wake. I knew having options might confuse folks but options are good.
The Overkill Heavy Duty Dock Springs have a spring rate of 2100 lbs. per inch and a one in thick solid steel bar compression links. All the others use 3/4" solid steel bar. They were created to handle the big dock loads seen on Lake of the Ozarks. If you have a large heavy dock on a main channel, these are what you will want.
Do you install different size springs on each side of the dock depending on which one has more tension because of current and wind?
Both sides should use the same size as wind comes from all directions. The current at my dock runs both ways, depending on wind. I have also talked to dock owners with 4 springs on their dock. Overkill is underrated. Call if I can help.
Do they go on the dock side or anchor side.
They go between your cable end and what it is normally attached to. Some docks have the winches on the shore and some have them on the dock. Install the spring on the end of the cable opposite the winch.
Any issues with the eyelet pulling through the aluminum channel at the attachment point if In the dock side?
If you have had a problem with an attachment eyelet pulling out on your aluminum dock, I would put a steel backer plate on the backside of the attachment to spread the stress over a larger area. Saw this same problem on next door neighbor's dock. I made a 4" x 8" x 1/2" steel plate with a 9/16" hole popped through it for a backer. Been solid ever since. See the dock bulletproofing page.
What warranty do you provide?
Dock springs are made from very heavy duty components. The springs are OEM quality heavy truck springs and the compression links are 3/4" cold rolled bar stock. You could spend a full day pounding on them with a hammer and not break them. If however, you do experience a failure due to the materials or workmanship, I will happily exchange them. One thing you will find in almost every warranty is the phrase, "acts of God". There are conditions that exist in nature that will rip your dock off the shore, turn it upside down, boats on lifts and all, and stomp it like a bug. Nothing associated with a heavy duty spring on your anchor cables will mitigate that. So, if God breaks it, you are on your own.
How long should they last?
They are made of steel. Heavy steel. UV light won't break them down or weaken them. They may get a little surface rust on them in areas where the paint wears off but you won't live long enough to see a set fail from corrosion. The springs are brand new and designed to support a truck over hundreds of thousands of miles. They will not break from use. You will not wear them out. They will have a very easy life of absorbing your dock's movements.