Marine Surveys by Gudgeon & Pintle Marine Surveys, Stephen T. Duncombe, SAMS® SA, New Bern, North Carolina, USA Gudgeon & Pintle Marine Surveys

New Bern, North Carolina, USA
Serving The US East Coast

Stephen T. Duncombe, SAMS® AMS®

Principal Marine Surveyor
Cell: 252 626 3281

High Water Bilge Alarms and Mixing Elbows -
In looking over the year 2015, 2 items come to mind that can save lives and property and are relatively simple to use and install.

1. High water bilge alarms

The American Boat and Yacht Council recommends that a high water bilge alarm be installed in any boat with an accommodation space. My concern here is with boats without an accommodation space, such as a center cockpit fishing boat.

Many of these boats have limited access to the bilge space: usually two or three 10" diameter inspection ports. The through hulls and seacock for the bait tanks and live wells are usually somewhat accessible via the ports. If any of the hoses were to break and allow water to flow and the bilge the only outward indication would be the boat settling lower in the water. Discovery at this juncture is almost too late.

Early in 2014, I was called in on a claim involving a 29 foot fishing boat that sank 30 miles off the coast. The boat had 2 outboard engines, and the only through hull fitting was for the bait well. The 3 men on board were fishing when they notice that the boat was low in the water. The Capt. tried to start the outboard motors, and called a Mayday. The boat sank within 15 minutes. Capt. and passengers were in the water for an hour before being rescued by a passing freighter.

A simple buzzer or alarm fitted to a float switch mounted high on one of the stringers under the might have prevented this sinking. A number of equipment manufacturers sell high water bilge alarms. Making one yourself with a float switch, wiring to the battery and wiring to a horn or some sort noisemaker should be well within most do it yourselfers ability.

2. Engine Exhaust Mixing Elbow

The mixing elbow of an engine's exhaust system can only be inspected visually during the survey. My technique is to tap the steel elbow with a hammer, particularly the underside of the elbow . In extreme situations the hammer has penetrated the mixing elbow, but otherwise hitting the elbow with a hammer does not tell much.

The mixing elbow mixes the exhaust gases and the engine cooling raw water. As you can imagine, the elbow can get very hot and when you add the salt from seawater, you get a superheat heated corrosive situation. The corrosion or rust within the elbow will inhibit the flow of water creating heat and back pressure that will cause either the engine to overheat or the exhaust gasket to blow.

In most sailboats there is usually only one exhaust elbow, but in twin-engine boats there can be upwards of 4 mixing elbows. Mixing elbows on gasoline engines seem to be particularly vulnerable. Many of the manufacturers include replacing the elbow as a routine at certain hours. The rule of thumb, absent manufacturer's info, is every 500 hours.

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Installed September 14, 2008, Last Revised May 28, 2020 - This site is hosted and maintained by Don Robertson