Sep. 02, 2024
by B.J. Porter (Contributing Editor)
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Once upon a time, a more naïve boat owner than me asked a service technician &#;So, do you know any marine plumbers?&#; That got a good laugh from him. Because unlike plumbing in your house, there&#;re no pipefitters union, no callout service, and no special trade that does marine plumbing. Boat yards and technicians can help with plumbing, but there are no specialized rooter companies or emergency callout services for boats. (OK, it was me who asked. It was a long time ago, and I needed help!)
One reason is that every boat&#;s plumbing is a little different, and there&#;s no standardization like there is in a house. Believe it or not, there are more complex issues with watermakers, water tanks, holding tanks, vented loops, and so on, and every boat is a unique mix. Boat plumbing systems use the same parts, although they may be arranged differently on similar ships.
We can&#;t solve your plumbing problems here. But what we CAN do is give you some tips and pointers, so if something goes wrong, you have a chance to fix it. And maybe a chance to be a little more efficient, save a few bucks, and come away with fewer cuts and bruises than I did.
Houses are square and don&#;t move, so fixed PVC, PEX plastic or even copper plumbing works pretty well. But boats are weird-shaped and they vibrate a lot. To absorb vibrations and navigate tight spaces, boat plumbing uses hoses, fittings, and clamps.
Each application requires a specific hose, such as reinforced high-pressure hose for water lines and sanitation hoses for plumbing. You can&#;t use engine hose to plumb your toilet, it will saturate and smell. And clear, un-reenforced water hose will eventually collapse if you pressurize it. You need the right material, diameter and type for your application.
Since you&#;re not building your boat, you have an easy guide to what hose you need for replacement &#; the old hose that failed!
Search the length of hose. Usually there are numbers and letters on it somewhere. They may be a part number with a brand, or even better, a description of the diameter and type of hose. In the worst case, bring a segment of the hose with you to the chandlery. They won&#;t love you for it if it&#;s sanitation hose, but you need to match it.
They often give hose with two diameters &#; the Inner Diameter (ID) and Outer Diameter (OD). For marine hoses, we only care about the ID. When you&#;re selecting fittings, they&#;re measured for the ID. So you get hose to match &#; a 1/2&#; hose barb needs a 1/2&#; ID hose.
Be careful when &#;eyeballing&#; hoses to get measurements, once the hose is cut in the store, there are no refunds. Measure the opening, or find the numbers on the outside. Measuring a fitting is less reliable because they often have tapered shapes, ridges, or flanges to hold the hose and create a seal.
Do NOT use the wrong size hose with a fitting. A larger hose over a smaller fitting will leak, eventually. This is important if you have SAE (English) diameter fittings and a metric ID hose or the reverse. Sometimes it&#;s close enough, like a 25mm hose on a 1&#; barb. But it&#;s better to err on the size of too small. If the hose does not fit snugly over the barb, no amount of clamping will guarantee it doesn&#;t leak.
Ever stick your fingers in one of those finger cuff toys and try to pull them out? The toy collapses on your finger, and you can&#;t get it out. An old hose on a hose barb does exactly the same thing when you try to pull it off!
Getting old hoses off and putting new ones on is half the battle in any plumbing repair, since the fittings need to be tight. Once a hose has sat in place for a few years, it deforms to the fitting, and deposits may build up to help hold it on.
If the hose is trashed, you can easily cut it off with a razor. But if the hose is still good, you&#;ll want to work it off and reuse it.
An inexpensive heat gun is indispensable for dealing with hoses. Gentle heat softens most hoses and makes them easier to stretch and work off. Warming the hose can loosen up the &#;stickiness&#; some hoses seem to get after a while, too.
You don&#;t want to melt the hose, which is why you use a heat gun instead of a flame. In a pinch, you could use a hair dryer, but a heat gun is warmer and does a better job. Heat all around the hose, and gently work it off as it softens. You may also gently slide a flathead screwdriver in the hose&#;s edge to get it going and break the seal, but don&#;t push it through the hose.
When putting a hose back on, you can reverse the technique. Some hose, especially sanitation hose, is quite stiff and doesn&#;t stretch well over fittings. But with a gentle warming on the end, and it will stretch right over it and mold in place.
You can buy &#;hose lube&#; to help get hoses on, but be careful which lube you buy if it&#;s not at a chandlery. First, it should be compatible with your hose material. And if it&#;s for a hose in your fresh water system it should be labeled &#;food safe.&#;
Dish soap is also pretty good lubrication, and it&#;s cheap and readily available. And you know it will be food safe and non-corrosive.
Just rub some of the soap or lubricant on the inside of the hose you&#;re installing for the first inch.
Hose clamps can be tricky things and give you a nasty cut if you&#;re not paying attention to them. A few general tips for using hose clamps:
If you&#;re clamping a hose to a fitting under the waterline, always put two hose clamps on the fitting. The only exception is if the fitting barb is too short, but then you should consider replacing the fitting with a longer barb. Always double clamp all raw water intakes, outflows, and exhaust plumbing, as this is a critical safety issue.
Some will argue that you should put the clamps on opposite directions, or opposite sides of the fitting. The science behind this is less clear. But you should offset the clamp screw barrels enough that you can put the clamps close together. If you can put them on opposite sides of the fitting, well it can&#;t hurt.
You can single clamp the fittings in your freshwater system, although there is no harm in double clamping them. This will decrease failure rates and leakage.
Your through-hulls and seacocks will often be made from bronze or Marelon, and you will find other pieces of hard plastic or metal in your system. Hose barbs we&#;ve talked about, but what about screwing two pieces of hardware together?
Almost all straight screwed-together fittings will benefit from Teflon plumbing tape. This tape will lubricate the threads to allow you to twist them tighter, and it will help seal the threads.
If a joined fitting is leaking, try taking it apart, adding a couple of wraps of plumber&#;s tape, and re-tighten. Often that stops the leak.
When putting plumber&#;s tape on, wrap it in the direction you are tightening. It will tighten more smoothy and not slip or bunch. I always end up thinking &#;righty tighty&#; and sometimes dry fit the pieces to make sure I put the tape on the right way. It works for me, don&#;t judge.
THERE ARE EXCEPTIONS TO PLUMBERS TAPE! If you are connecting a flared or compression fitting, you should not use tape unless you know it won&#;t cause a problem. Some specialized fittings are tapered or require metal-on-metal contact to seal, and the tape may keep them from closing properly. This is usually with some propane fittings, but not unheard of in water systems.
There are a few things you can keep on board to help you with problems if they happen away from the dock. This includes:
Most plumbing troubleshooting is fairly straightforward if it involves a leak. If you&#;re lucky, it&#;s a water leak and you can see a small stain, puddle, or drops to show you exactly where your problem is. Sometimes you can&#;t see a leak, but you can run your fingers over the hose and the joint to feel for any wetness or cold. Remember than water can travel, so you need to keep checking above the place you first find a wet spot.
Then you need to figure out if it&#;s a loose connection, or a worn or broken fitting or hose. The most common time to discover a broken fitting is in the spring, after a poor winterization job. So be careful and start slow when you recommission!
If you&#;re less lucky, it&#;s an air leak. Some parts of your system rely on vacuum principles, like the pump that draws water from your fresh water tanks. If there is an air leak in the uptake line, it may not be able to draw water. But it may not be leaking water if the air leak is near the pump since it can&#;t draw water up there.
Again, it can be a something loose or something broken. So the first step is step is to check tightness &#; you&#;d be surprised how often a turn on a hose clamp can solve a problem!
Finally, if you&#;re flat-out unlucky, it&#;s a black water leak. The good news is catastrophic black water leaks aren&#;t all that common. Most black water issues are blockages or smells. Hoses get saturated over time and smell, and it&#;s possible to get some oozing and weeping around the connections that can lead to smells. The best solution in both cases is to replace all the hoses.
If you have black water leaks, they usually happen the same way as fresh and raw water leaks &#; loose connections or broken hoses or fittings. They&#;re messier, but you fix them the same way.
Operator error causes a lot of plumbing problems. Overfilling holding tanks, improper winterization, and so on. So many toilet problems are caused by flushing inappropriate objects.
Take extra care with guests on board, as they&#;re the most likely to make plumbing related errors. We used to joke about &#;potty training&#; guests on board when they arrived, but a minute spent explaining how to use the head and what not to put in it can save you a load of trouble. (&#;nothing you didn&#;t eat or drink first, or pull from that roll there&#;)
Hopefully, you won&#;t have any big plumbing problems when you&#;re out enjoying your boat. But if you do, you can have some idea how to fix things!
Maintaining your marine sanitation device can be an onerous task, but this need not be the case since problems that arise have more to do with owner neglect than anything else. Sure, sometimes components like Y-valves, macerators, holding tanks or even an entire system must be replaced; but squarely facing these problems is a lot better than avoidance, especially when you consider the convenience that a properly installed and maintained system brings to a boat. This article will acquaint you with typical installations, system maintenance and laws that govern marine sanitation system use.
If you want to learn more, please visit our website marine sanitation hose.
Related links:All boats operating in US waters with permanently installed toilets are required by federal law to have a Marine Sanitation Device (MSD) on board that either stores human waste until it can be transferred ashore, or reduces the coliform count to such low levels that discharged sewage poses no public health hazard&#;even in populated harbors. While the MSD must satisfy Coast Guard regulations, the boat owner still has a lot of choices of product types and overall system design.
The Raritan Electro Scan utilizes electrodes which temporarily convert salt water into a powerful bactericide. The treated wastewater then safely and conveniently reverts back to its original state of salt and water which meets EPA Type I standards for overboard discharge.
A rapidly increasing number of coastal areas have been designated as No Discharge Zones. To qualify under the federal Clean Water Act, states must show that sufficient pump-out facilities exist for boaters to empty holding tanks. In Michigan, New Mexico, Rhode Island and Vermont all waters are no discharge. There remains considerable opposition to NDZs from boaters who feel both inconvenienced and unfairly singled out as sources of pollution (miniscule compared to typical sewage treatment overflow following rainstorms, runoff, and industrial effluents), but the political tide definitely favors the proliferation of NDZs.
There are a variety of ways to deal with waste on board, including recirculating, composting, and incinerating toilets, but by far the most common are toilets plumbed to holding tanks. These range from the simple and inexpensive self-contained heads (portable potties) to fairly complicated systems incorporating multiple valves, pumps and hoses. Any way you look at it, carrying around sewage is necessary.
While pumping raw sewage is not illegal offshore, you need an approved MSD for inshore and inland use. Direct discharge is foul, and&#;inside the three&#;mile limit, illegal. Don't operate your head without a means to contain or treat waste on board, and in foreign countries don't pump your waste overboard within 100 yards of the beach. This is harmful to swimmers and those who eat the local fish and shellfish. Just because the hundreds of Caribbean charter boats have little, if any, sewage treatment systems on board doesn't mean it's okay for the rest of us to dump in the otherwise pristine waters regularly used by snorkelers and swimmers.
This is a solution for thousands of "weekend" or trailer boats that need a way to hold small amounts of waste (usually limited to six gallons). They aren't fun to take on shore and dump (usually in a marina toilet), but they eliminate the need to install permanent plumbing, are almost impossible to clog, and are inexpensive. If you add a deodorizing chemical to the tank, these heads are reasonably odor&#;free.
For areas with adequate pump&#;out facilities, a holding tank connected between your head's discharge and a through&#;deck fitting is a fairly simple, inexpensive installation, and meets the requirements of the law. We offer holding tanks as small as three gallons, although we strongly recommend installing a larger tank if you have the room. A full crew in party mode can fill a small tank in no time, especially if they are vigorous flushers (actually recommended to keep waste from collecting in hoses). The drawback with this method is that you have no place to go if your tank is full and you cannot find a pumpout station fast. Boaters on the Great Lakes, however, have been successfully living with these restrictions for decades, so it can't be that bad.
In addition to the standard deck pump&#;out fitting, a Y&#;valve between the toilet and tank allows you to pump directly overboard when beyond the three&#;mile limit. In harbor, use the holding tank. Offshore, dump directly overboard. There are two serious drawbacks to this approach, however&#;the risk of accidental discharges (which is why some authorities frown on Y&#;valves upstream of the holding tank), and the inability to empty the holding tank at sea.
All of the waste is pumped into a holding tank, yet you have the option of pumping it overboard when legal and logical to do so. There's no Y&#;valve between the toilet and tank to upset authorities. Inshore and inland, the tank is emptied via the deck pipe. Offshore, you can empty the tank yourself using a manual or electric pump. A Y&#;valve downstream of the tank allows you to choose between the two.
As with most systems, a clogged valve or hose can make for an ugly service job. And you run the risk of not being able to use the toilet until the system is freed. A Y&#;valve between the toilet and tank solves that predicament (go ahead, get out the cleaning bucket!), but again could get you cited by the potty patrol.
On smaller boats, manual heads are most common due to their simplicity and low cost. But it has always amazed us that builders of even expensive yachts often install the lowest cost heads. Because toilet trouble at sea is extra nasty, we think this is one piece of equipment worth spending a little extra on. Here are some features to look for:
Jabsco Quiet Flush Electric Head includes a water control solenoid valve with anti-siphon braker to prevent contamination of potable water supply.
A lot of people scoff at electric heads as extravagant energy wasters. But because the electric pumps run so briefly with each flush, the total current consumption is actually quite low. The Jabsco Quiet&#;Flush Electric Head, for example, draws 10A, but with a 30-second flush cycle, total energy used per flush is just 0.15Ah. Advantages of electric heads include easier operation for inexperienced guests, and less chance of clogging because the built&#;in macerator evacuation pumps grind up waste and toilet paper before sending it to the holding tank.
Most head systems use a 3/4" intake seacock and thru-hull for seawater flushing, and a 1 1/2" seacock and thru-hull for overboard discharge. Bronze fittings are most common because of their strength and durability, followed by Marelon fittings for their nonconductive, noncorroding nature. For these reasons Marelon fittings are often used on metal boats.
All types of sanitation hose will eventually smell if sewage is allowed to stand for extended periods of time. We recommend only smooth interior wall hose because corrugated types trap waste and restrict flow. Rigid PVC does not pass odors but is more difficult to route and does not connect directly to pumps and thru-hulls. Still, it's possible to plumb part of the system with rigid PVC, switching to hose where necessary. The best hose for containing odors is SeaLand OdorSafe Plus, followed by Shields Heavy Duty Vinyl Hose (#148) or Super Head Hose (#101). All of these hoses are resistant to odor permeation.
To reduce the chance of sanitation hoses emitting a foul odor, be sure to flush the system after every use. Hoses should be installed without any low spots where waste can collect. Heating hose to fit over barbed adapters can dangerously weaken the hose. Instead buy fittings specifically made for 1 1/2" sanitation hose.
Using your limited supply of fresh water to flush the head seems like a ridiculous waste, but electric heads from Jabsco and SeaLand use very little water&#;some models as little as a pint or two. And freshwater flushes greatly reduce bad odors in the system caused by all sorts of microorganisms dying and decaying in the bowl&#;plankton, krill, you'd be surprised!
Below-waterline installation requires vented loops to prevent back-siphoning (and potential sinking) when the boat heels.
A common cause of boat sinkings is from backflow created by siphons in the head and engine seawater intake hoses, and head discharge hose. Vented loops installed in the hose above the waterline prevent siphons from occurring and don't impede normal flow. They're usually mounted against a bulkhead. We sell both bronze and Marelon models.
Thick-walled (1/4" or thicker) high-density polyethylene tanks are the most sensible choice. They are light, won't corrode and are much less expensive than metal or fiberglass tanks. While thinner wall tanks rarely burst, they can bulge so much that fittings are stressed to the point of leaking. Your nose will alert you, but it's safer to buy a quality tank in the first place. We sell Todd and SeaLand tanks in various wall thickness. Taller, narrower tanks can be emptied more completely but are more difficult to secure. Plumbing attachments should be as low and as high on the tank as possible. Flexible tanks can be used when spaces are oddly shaped or inaccessible but they lack the odor resistance and strength of rigid tanks so we don't recommend them for waste.
We feel the best Y&#; or diverter valve is made by Whale, in part because it has a center position that closes both ports. Other brands, however, may integrate into your plumbing more conveniently depending on the direction your hose runs. The Bosworth Y&#;valve can be surface&#;mounted so that you don't have to climb into a tiny locker to change directions. Forespar's Marelon valves are very strong, and Jabsco valves can be adjusted to a variety of configurations and are lockable for USCG inspections.
Discharge pumps are used to empty the holding tank overboard. We recommend large diameter diaphragm pumps because they are the least likely to clog. The Whale Manual Waste Pump is the best choice among non&#;electric pumps. Unlike aluminum-body pumps, its plastic body won't corrode. Macerator pumps, such as those by Jabsco and SHURflo, grind waste for easier passage through the sanitation system. When used as discharge pumps (from holding tank to overboard) be very careful to monitor the tank level because they can burn out pretty quickly if run dry.
A more durable solution for pumping holding tanks is the SeaLand T Series Discharge Pump diaphragm pump, which can be run dry without damage, or the Whale Gulper pulverizer toilet pump, which can handle solids up to 1 1/2".
Be sure your seacock is open before trying to pump out the tank. When an electric pump tries to pump against a closed outlet its valves can sometimes become inverted which requires a sewage "project" and even if the pump isn't damaged, you could cause a rupture in the system.
Tank level indicators reduce the risk of overfilling the holding tank, which can push sewage out the vent line, or, if that line is clogged, rupture the system elsewhere. Mount monitors near the discharge pump switch so you can empty the tank as soon as you determine the tank is nearly full.
Holding tanks that contain waste also contain aerobic (good) or anaerobic (bad) bacteria. Aerobic bacteria require oxygen to live and reproduce. As aerobic bacteria break down waste they produce carbon dioxide gas and water, which are both odorless. On the other hand, anaerobic bacteria thrive in the absence of oxygen. As anaerobic bacteria grow, they produce sulfur monoxide and sulfur dioxide gas with the characteristic rotten egg odor.
One way to prevent holding tank odors is to encourage the growth of aerobic bacteria with increased ventilation. On most small boats, tank vents are 5/8". Ensuring that the hose that leads to the tank vent is not obstructed is a start. Another option is to increase the size of the vent and even to locate larger holding tank vents on both sides of the boat to create cross ventilation. While this is a sound idea, it may not be practical for many boats.
This leads us to the alternatives, which are head and holding tank treatments that employ a variety of methods to mask or eliminate offensive odors created as waste is broken down. For more on these treatments, see Head and Holding Tank Treatments.
Marine sanitation has come a long ways since the days of cedar buckets. Joshua Slocum would probably have found the idea of carting waste around in a holding tank ridiculous. However, Slocum was just one person, who in the course of being the first mariner to sail singlehandedly around the world would have produced an immeasurably small effect on the environment. Today, there are thousands of cruisers crisscrossing the seven seas. Creating and maintaining a sanitation system isn't hard and we owe it to each other to leave a clean wake.
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