T-H Marine Boat Hardware & Plumbing

T-H Marine Boat Hardware and Plumbing Resources and Information 

Partsvu is thrilled to offer a selection of boat hardware and plumbing components to fit your boat’s exact specifications. Browse T-H Marine boat products by category, including marine pumps and plugs. Use these essential plumbing products to repair and replace the plumbing system on your marine vessel. 

Looking for other marine products? Take a look at PartsVu’s selection of marine parts and products or browse more T-H Marine boating essentials.

T-H Marine Boat Hardware and Plumbing FAQs

What is a boat holding tank?

The holding tank is responsible for holding the water that is used in your boat’s plumbing system. These tanks are heavy– especially when they’re filled with water –so they should always be installed low in the boat. Holding tanks are usually made of hard polyethylene, and are available in a variety of sizes and shapes to fit your unique type of marine vessel. Holding tanks are also available as flexible bladders.

A typical holding tank features three ports: one for the outlet, one for the vent, and one for the fill hose. The fill hose connects to a port on the boat where freshwater can be refilled. The vent port connects via hose to a vent high up in the boat, so that air can escape. The outlet runs via hose to the pump. 

What is supply piping?

Supply piping moves the water around your boat’s plumbing system. Because these pipes carry drinking water, they must be FDA-approved to ensure that the water is non-toxic, tasteless, and contaminant-free. Traditionally, supply piping is made of PVC, but recently polyethylene tubing, like the kind used in RVs, has become increasingly popular. The opaque nature of PE tubing discourages algae growth, and it comes in different colors, which helps keep track of different water lines– such as hot and cold water, or gray water and fresh water. 

What does a water pump do?

The water pump is responsible for maintaining the water pressure in your boat’s plumbing system. There are two kinds of water pumps: electrical and manual. An electrical water pump typically maintains water pressure somewhere between 30 and 40 PSI. Whenever a faucet is activated on your boat, the water pump comes on and restores the water pressure. The pump is supplied via piping from the water tank’s outlet. 

A manual water pump is activated manually, each time the user wishes to draw water. While this type of water pump is more difficult and time-consuming to operate, it wastes much less water than an electrical pump, making a manual pump a good choice for boaters intending to spend long periods of time away from the shore. 

What is an accumulator?

While not included in every plumbing system, an accumulator can conserve water and reduce electricity usage. Accumulators work by receiving water from the water pump and using compressed air to move water through the supply piping. This allows water to stay pressurized without the water pump activating, reducing the need for the water pump. 

What does a marine water heater do?

As the name implies, water heaters heat the water in your boat’s plumbing system. A water heater is an insulated tank that connects to the water pump. Once water is pumped into the water heater, an electrical heating element heats the water to a temperature predetermined by the water heater’s thermostat. 

What is a faucet? 

Faucets are the end-point of your boat’s plumbing system. There are typically two types of faucets: single-handle and dual. While dual faucets feature two knobs– one that controls cold water, one that controls hot water –single-handle faucets use only one lever to adjust the water temperature. While the single-handle faucet features only one handle, it still requires both a hot and cold water line. 

How do drains work in a boat plumbing system? 

Drain lines are run through the boat’s hull. These lines to a bilge pump which pumps the water overboard. While boat showers can be drained into the bilge, hair and other debris can clog bilge pumps, leading to backed up, or foul odors. We recommend isolating shower drains from the bilge by using a discharge pump. Make sure that your discharge outlet always remains above the water line.

What is a washdown? 

Unlike the rest of the components of a boat's plumbing system, the washdown pump is not connected to a clean water source. Instead, the pump’s inlet sits below the waterline, so that the pump draws water from the body of water. This water can be used to wash down the deck during cleaning by connecting a rubber hose to the pump’s outlet. 

What is T-H Marine's warranty policy?

T-H Marine Supplies, Inc. warrants to the first retail purchaser of its products that T-H Marine Supplies, Inc. will replace or repair the product, at its sole discretion, if any defects in material or workmanship are reported within the applicable warranty periods set out below from the date of the first retail purchase, subject to the remedies, exclusions, and limitations in this Limited Warranty. This limited warranty is effective for all T-H Marine Supplies, Inc. products purchased after January 1, 2007.

1. ATLAS Hydraulic Jack Plates*: Relay Harness — 1 Year; Actuator mechanism – 3 years; Jack Plate Frame – Life of Boat (for the original purchaser)
2. ATLAS MICRO JACKER: 1 year all-around warranty
3. BLUE WATER LED lights have a Limited Lifetime Warranty
4. All other T-H Marine Supplies, Inc. products: 1 year

How do I winterize my boat’s plumbing system?

Winterizing your boat is essential for protecting vital engine components during storage. It’s no less important to winterize your boat’s plumbing system to prevent issues like burst pipes or a damaged holding tank. When water freezes, it expands. If this expansion puts too much pressure on your boat’s supply piping or the holding tank, the walls could fracture and burst, resulting in costly equipment repair and water damage. To get your plumbing system ready for winter, begin by draining your water lines, including the water in your holding tank. If you want to treat your system with an anti-freezing treatment, be sure to use one that is non-toxic and intended for a potable water system. Also, make sure that the anti-freezing chemical doesn’t react badly with your supply piping material. 

Is the engine cooling plumbing system separate from the domestic plumbing system?

The short answer is yes. The plumbing system responsible for cooling your boat motor is a completely separate system from the domestic plumbing system. The domestic plumbing system transfers potable water either from the holding tank to the faucets, or from the drains to the bilge. 

The engine’s cooling system relies on a network of tubing and an impeller that transfers raw water through the lower unit to keep vital engine components cool. The water is then discharged through an outlet commonly called a “wet exhaust”. 

What kind of hose should I use for my outboard engine plumbing? 

 The hose used for transferring water through an outboard motor’s cooling system needs to withstand the pressure of the suction created by the impeller. For this reason, a reinforced hose is required. For boats with a wet exhaust, the water mixes with exhaust, which in turn heats the water, meaning the hose will be subject to intense heat when expelling the used water from the engine. That means a heat-resistant hose is required. 

What is the advantage of a wet exhaust system? 

Unlike exhaust systems that deal with exhaust fumes and water separately, wet exhaust systems are quieter, cleaner and it keeps the engine much cooler.