Discount Inboard Marine (DIM) Featured Product(s)

Sherwood Sea Water Strainer Engine Alarm with Audible Warning

Inexpensive Protection for Your Engine
By Keith Bagley, CorrectCraftFan.com
August 2004

Previous DIM Featured Products: ACME #540 13" x 12 pitch 3-blade NiBrAl

Without the benefit of a radiator and a constant 65 m.p.h. wind, your large, high performance, high RPM, marinized car engine in your Correct Craft can overheat in mater of seconds. This is why it is vital to have a ample supply of free flowing, cool lake water running through your 'open' cooling system at all times.

The leading cause for overheating among inboard marine engines is a clogged intake line, usually at the oil cooler, or a damaged impeller. And the real issue comes when a sudden supply of cold lake water bursts its way through the previously choked cooling system and into your 200 plus degree overheated engine – the cylinder heads crack, ruining your summer as you spend valuable time and money rebuilding the engine.

A simple and inexpensive solution is to add a Sherwood Sea Water Strainer to your cooling system to prevent system failure and an accompanying Audible Engine Warning Alarm to notify you of any danger. Newer Correct Crafts come with these devices installed but the older boats did not.

Sherwood Sea Water Strainer

Strainer with two hose barb connectors

The Sherwood Sea Water (or raw water) Strainer mounts inline with the raw water intake and filters out aquatic vegetation, leaves, rocks, helpless fish and other debris before it reaches the narrow passages of the transmission oil cooler and the venerable impeller. Designed to provide full-flow, the stainless steel screen traps debris in a see-through plastic bowl where you can easily spot any foreign objects that where sucked in with the lake water. You can then simply remove, clean and then reattached the screen and bowl all by hand – no tools required.

My 79' Mustang has a Ford PCM 302 which uses a 1 inch raw water intake hose. I ordered the 1 inch strainer (also comes in 1 1/4 inch) and two of the straight 1 inch hose barb connectors (also available in 90 degree) from SKIDIM.com. Installation could not have been simpler as it took only about 20 minutes and could be done right at the dock.

Strainer installed

First, I wrapped the threads of each barb connector with plumbers tape and screwed them into both the 'in' and 'out' sides of the Sherwood strainer. I then measured the length of the unit to determine where it would fit best along the path of the raw water intake hose somewhere between the through-hull pickup and my oil cooler unit. Next, I cut the hose at the desired point and pushed each end of the newly cut hose over the barbed connectors, careful to mount the strainer in the proper direction of water flow -- indicated on the strainer by a large arrow molded right into the plastic. Finally, I took two stainless steel hose clamps (available at any hardware store) and tightened them over the barb connectors to insure a secure, leak-proof connection.

That was it, a simple and quick installation. Now every time I take the boat out, I open the engine cover and take a quick look at the strainer to see what I've 'collected'. If I see some debris in the strainer, I simply unscrew the bowl by hand, dump the debris back into the lake, and then screw the bowl back on. It's a slick system and beyond saving my engine and transmission for serious overheating problems it will certainly prolong the life of my impeller.

Audible Engine Alarm
The Audible Engine Alarm works just like a warning light – a warning light you can hear. It's designed to work in conjunction with your existing temperature and oil pressure gauges. If you’re like me, you check your temperature and oil gauge often but you have plenty of other things that grab your attention while out on the water. Also, you get nervous whenever someone else, who is less accustomed to watching gauges, drives your boat. This alarm solves these problems and can also act as a backup for your exiting gauges.

Alarm mounted under dash

The alarm is mounted under the dash with the positive side connected to the 'key on' power supply. The ground is then connected to a new temperature sending unit and a new oil pressure sending unit (included in the kit). The temperature sending unit is set to 200 degrees Fahrenheit and the oil pressure sending unit is set to 6 p.s.i. When the temperature goes above 200 or the oil pressure drops below 6 p.s.i., the relevant sending unit grounds to the engine which completes the circuit to the alarm causing it to sound.

My PCM 302 has a spot for a second temperature sending unit in the top of the intake manifold, aft of the carburetor. I simply removed the plug and screwed in the new sending unit. Please note: According to Woody from SECC, the plug aft the carburetor is for air, not water. He mentioned there may be another suitable plug in the water pump but I have not been able to confirm. There is only one spot for an oil sending unit so I went to my local hardware store and purchased the parts to create a 'T' using brass, 1/8 inch thread plumber fittings. I removed the existing oil pressure gauge sending unit, installed the 'T', then installed the two sending units to either end of the 'T'.

New oil pressure sending unit installed

Lastly, I ran a ground wire from the new oil pressure sending unit, to the new temperature sending unit, to the ground (or negative) side of the audible alarm I had mounted under the dash. I used two coat hangers to feed the wire from the engine compartment through the existing wiring tube and up to the dash. The installation was really very simple and straight forward.

One of the best things about the alarm systems is that since there is no oil pressure when the engine is not running, every time you turn the key to start the boat, you hear the alarm until the engine starts. It's like a test that the system is working properly and it also gives other drivers, those new to you boat, a sample of what the alarm sounds like. And I can tell you, you'll never mistakenly draining your battery by leaving your key on again.

The combination strainer and alarm make for the perfect upgrade for older Correct Crafts. The strainer protects your engine from harmful debris being sucked up through the intake and the alarm warns your of potential problems. Never again will you wonder if those lily pads will make it past your impeller or stress over whether your brother in-law knows what the temperature gauge is? This inexpensive but very important upgrade to our older Correct Craft will give you piece of mind and should ensure the safety of your engine for years to come.