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We flip a switch or start the engine and we get hot water, but it doesn't last forever

Replacing the Water Heater

On a recent Sunday morning my wife noticed steam coming from the bilge area and so we had a look and found steam and hot water coming from the water heater. I turned off the bilge pump and added some bilge cleaner, mulling over the problem. How much would it cost? Would I be able to replace it myself? I then rocked the boat for a while before turning the bilge pump back on.

On Monday I shopped around and found that the Defender had the best price, $199.00 including shipping. It was ordered on Monday -- it arrived on Friday.

In order to get the water heater out, the drawer assembly under the sink has to be removed to get access to the rear of the heater. The removal requires the bungs over the screws in the drawer assembly to be removed. Before the assembly can come completely out the companionway ladder has to be removed.

Here are a couple of photos of the rear of the old heater.

I removed the hoses from the engine and connected them together with a 5/8” connecter. This kept the coolant from running out.

The front of the heater is accessed from the port settee.

I removed the hoses from the front of the heater and then was able to remove the heater from the rear.

This is the old heater out of the boat:

The platform that the heater was mounted to was covered in rust, but was still solid and permanently attached to the hull. I cut a new piece of plywood and sealed it and then painted it with West Marine Bilge paint.

I had to increase the fore and aft length of the platform to accommodate the longer mounting flanges of the new heater. This is the only dimension that changed.

I had enough clearance above the heater to add the ¼” thick plywood on top of the current platform. I then was ready to put in the new heater. It went in rather easily and I was able to secure it to the new platform and connect all of the hoses. The electrical connection was the last thing I hooked up.

It took me about five hours to replace the heater: Two hours for the heater, and three hours to fix all of the leaks and replace hoses and clamps. Since I replaced the water heater and fixed the other leaks, my bilge pumps only runs when there is rain water in the bilge.

This project was rather easy because of the information I was able to get from the Catalina Website message board and email list. The help, advice and encouragement available on the website and the email list makes almost any project doable. If you're thinking about replacing your water heater, there are three things you want to remember:

1. The Seward replacement heater is the same size as the original, but with longer mounting flanges

2. The drawer assembly has to be removed so the heater can be removed.

3. Have a 5/8” connecter ready for the coolant hoses so that there is little spillage

The replacement of the heater was not that difficult, but like most things pre-planning and knowing what to expect really pays off.

The skills required for this were at the beginner level and no special tools were required. I used the following tools during the replacement:

screw drivers

hose clamp nut driver

circular saw (to cut the new platform)

knife or hose cutter

Final note: The one thing I did not do, but wish I did, was to cut an inspection hole in the drawer assembly so that I could see the coolant hoses going to the rear of the heater.

Ralph Johnson
Still a Thrill #765
Lake Texoma, TX