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The Masthead


bout exhaust temperature sensors

and hose clamps from the Septem-

ber 2014 issues ABYC Tech Notes:



is well done again. (“But of

course,” you say.) However, the photo on

page 14 shows a wet exhaust system with

only one hose clamp on each end of the

hose from the elbow to the muffler as well

as the vertical hose from the muffler. ABYC

P- states, “Every exhaust hose

connection shall be secured with at least

two non-overlapping clamps at each end to

produce a secure, liquid and vapor-tight




Bob MacNeill

Dave Gerr Replies:

Thanks Bob. Right you are and a very important point! The

only thing we can do for someone demonstrating such per-

spicacity, insight and sagacity is to award you a Know It All

certificate. One is on it’s way to you as I write this.




Regarding the Sept.


ABYC Tech Notes:

The column is an excellent reminder of the value of this

component, as well as its need for ABYC compliance. I’m a

strong proponent of exhaust alarms, I’ve written about them

many times, and I recommend them to my clients and lec-

ture attendees, as well as in every vessel inspection report I

write. However, while I’m a fan of the concept, there’s no

love lost between me and exhaust temperature sensors that

pierce and live within the exhaust gas/water stream, like

the one shown in the image that accompanied the Septem-

ber 2014 column. Not only is this an incredibly hellish envi-

ronment from a corrosion perspective, I strongly suspect

that modifying FRP mufflers, or hoses where I’ve also seen

them installed, violates the manufacturer’s war-

ranty. Drilling and tapping FRP is also frowned upon. I’ve

seen piercing probes of this sort fail, blowing out, and creat-

ing a nightmarish and potentially dangerous mess as it fills

the compartment with exhaust gasses and atomized, hot

seawater, with the potential to cause tens of thousands of

dollars’ worth of damage, and worst of all the operator of

the vessel often has no indication it’s occurring until the

engine begins to stall as a result of exhaust gas and water

ingestion, at which point severe damage has already oc-

curred to much of the gear in the engine compartment.

My preference is for a thermistor type sensor, one that is

strapped to, rather than inserted into, the wet exhaust hose

just downstream of the injected elbow. The one I prefer is

made by Borel Manufacturing. Its quick-acting sensor is

never exposed to exhaust gasses or water and thus lasts

indefinitely (I have yet to experience a failure, and I’ve been

using them for over a decade). In many cases, it reacts so

quickly, that a blocked intake sets it off well before the raw-

water impeller is even damaged, and long before the engine

or exhaust system comes anywhere near overheating. I’ve

had countless users report instances where it saved them

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Photo from the September 2014 issue’s ABYC Tech article on exhaust-

temperature sensors

Dec. 2014 Page 28