What is Siphoning?
How do you drain gas from a fuel tank if you can't turn it over? Gravity has the answer, as you can drain gas from the top of a fuel tank into a container as long as the receptacle is lower than the fuel level in the tank. Siphoning the process of using gravity to empty out a fuel tank, and it's energy-free except when you start the flow.
If one of the tubes is lower than the other, fuel will actually flow up the hose in order to reach the lower end. As fuel flows down the longer end of the hose, it creates a vacuum that is strong enough to pull more fuel up through the high point and down to the secondary tank. Once this process begins, it'll drain an entire fuel tank without any extra force or user attention.
Siphoning works on its own after you get it started. The tricky part is starting the flow, as you need something to draw the fuel up the hose to get it to flow down to the lower point. There are several methods to start the flow, but some of which are dangerous, and others simply don't work well. That's where the shaker siphon comes in handy.
What is a Shaker Siphon Hose?
Fundamentally, a shaker siphon is just a tube with a self-priming pump on one end and an open hole on the other. A shaker siphon is designed to eliminate cumbersome or dangerous practices that are often used to start the flow when siphoning fuel.
Shaker siphons are simple, safe, easy to use, and reusable. They're also highly affordable and compact, which makes them a must aboard any gasoline or diesel-powered sailboat.
How a Shaker Siphon Hose Works
The purpose of a shaker siphon is to prime its hose enough to start the flow of fuel from the fuel tank. A shaker siphon has three primary parts: The tube, the pump housing, and the ball. These parts form what's called a check valve, which is designed to allow fuel to flow in but not out.
The tube is just a long plastic hose that's usually treated to prevent static electricity fuel-related defamation. The pump housing, which feeds onto one end of the tube, is a simple pipe fitting with a hole designed to fit the ball. The ball is larger than the diameter of the hole, but it's free to rattle around. It plugs the hole when there's back pressure in the line but unplugs it when it's pushed through the fuel.
When you shake the shaker siphon around the inside of a fuel tank, the back and forth movement pushes fuel into the tube incrementally as the ball plugs and unplugs the hole. Eventually, enough fuel will accumulate in the line to round the high point and start the self-sustaining siphon flow.
Siphon Hose Safety
Shaker siphons are much safer than many of the siphoning alternatives that are still common. For example, many people use the hose like a straw, which can make you unintentionally swallow gasoline. Shaker siphons keep gas out of your mouth and away from your face, which is a major improvement.
However, using a Shaker siphon has risks, and it's important to use it safely. Before using a shaker siphon, touch something metal (like a lamp post or a railing) to discharge any static electricity that may have built up. Additionally, keep all kinds of flame or ignition far from the hose in the gas tank.
Make sure electrical lines are covered and don't siphon gas while the engine is running. Obviously, don't smoke anywhere near the house. After using the Shaker siphon, turn it upside down so the valve opens in any remaining fuel drains out before stowage.
Keep a fire extinguisher close at hand, and only fill certified gas tanks with fuel. Gasoline can rapidly melt plastic containers that aren't designed for it. Also, filling containers that aren't meant for gasoline with fuel can be illegal and increase the risk of leaks, vapor problems, and explosions.
Steps to Use a Shaker Siphon Hose
Using a Shaker siphon is easy, but it's essential to use it properly to avoid spills, fires, and accidents. Here are the steps to using a Shaker siphon hose.
1. Setup
Unpack the shaker siphon and remove your fuel tank cap. Uncap your secondary gas tank and place it nearby, and make sure it's close enough but the hose to reach. Place your portable gas tank lower than the lowest point of your boat's fuel tank. If the portable gas tank is higher than the level of fuel in the boat's tank, it won't flow.
2. Position the Shaker Siphon
Place the valve end of the shaker siphon into the vessel's gas tank. The valve end usually contains a metal plumbing fitting, and it's easy to spot. Let the valve sink to the bottom of the gas tank, and stop feeding the hose when you hear the tell-tale clunk.
Then, position the open end of the hose inside your portable gas tank. Make sure there's enough slack to move the hose up and down without pulling it out of the portable tank.
3. Start the Flow of Fuel
With both ends of the shaker siphon hose placed inside of their separate tanks, grab the shaker siphon hose immediately above your sailboat's gas tank. Hold the other end steady in the portable tank to keep it from coming out, and 'shake' the valve end in an up-and-down motion. The up-and-down motion should be long and relatively slow, as your goal is to fill the hose with gas from the larger tank.
4. Controlling the Flow
To control the flow, find a spot in the hose and gently squeeze or kink it. This will also stop the flow if the hose is folded completely, but it may cause gas to run back down the other end of the line.
In most cases, you won't need to adjust the flow rate. This is because shaker siphon hoses are usually narrow enough to prevent fuel from flowing too fast. Kinking the hose is a way to stop you when your smaller tank is full, but you can also simply lift the smaller tank above the fuel level.
5. Finishing Up
Carefully watch the fuel level in your portable gas tank to avoid causing an overflow. When the tank is full, lift the valve out of your boat's gas tank and let the remaining fuel continue to flow into the portable tank. It's important to leave a little bit of space in the portable tank to allow the hose to drain into it.
With the portable tank full in the siphon hose empty, it's time to properly stow your shaker siphon. Cap both tanks and leave the siphon hose in a well-ventilated area for an hour or two.
Gasoline evaporates quickly, and leaving out the siphon hose ensures that it'll be dry when you put it away. Don't leave it in the sun, as he can damage the fuel hose and shorten its service life.
Shaker Siphon Hose vs. Siphon Pump
Shaker siphon poses a popular alternative to siphon pumps, which come in many varieties. A siphon pump uses either a squeeze bulb or a separate pumping unit to draw fuel in and start the siphoning process. Some siphon pumps don't use gravity flow at all and require continuous pumping.
The advantage of industrial-type siphon pumps is that they can be used to pump fuel above the level in the larger tank. This is useful if your gas tank is located deep in the boat, and you can't get a separate tank low enough for gravity feed.
Bulb-variety siphon pumps use gravity just like a shaker siphon. These units are widely available and are the most similar direct alternative to the shaker siphon. However, they aren't quite as robust, and they can't be easily modified with a longer hose.
At the end of the day, the shaker siphon and the siphon pump are similar enough that it comes down to a matter of personal preference. If you can use gravity siphoning on your boat, it really doesn't matter which one you choose.
When to Use a Shaker Siphon Hose
There are many situations where a shaker siphon can be useful. The most common shaker siphon use is to move gas or diesel out of a large tank and into a smaller tank. You can also use a shaker siphon to safely fill your gas tank from a smaller tank.
This is especially useful when at sea because pitching and rolling can make it difficult to fill the gas tank without spilling. Using a shaker siphon also makes it easy to fill gas tanks from larger tanks, as you don't have to lift the portable tank and angle the nozzle into a tiny filler hole.
