Our 9 and 12 inch Compact Axial Fans are now available for purchase online.

Engine Room Cool Down For The Opal Lady A Nordhavn 43

Nov 23, 2021

Brad Marsden

Director - Marine Air Flow International

35 Years Experience in the Marine Industry

View Brad's Info

43 Nordhavn Overheating Challenges

It was an absolute pleasure to work with Peter, Suz and Neon the cat, to help them reduce the engine room temperatures in their Nordhavn 43.


Peter has been very active in his efforts to decrease operating engine room temperatures in his and Suz's boat the "Opal Lady" and has over the years added extra axial fans to help reduce consistant +50 degree (c) temps. Unfortunately Peters best efforts were not helping on longer runs and he contacted us on advice from a friend in May of this year.


The Opal Ladys original intake air grille

After inspection of the Opal Lady we discovered that despite Peter's amazing efforts, the amount of air moving through their engine room just wasn't sufficient. Opal Lady's air exchange sat at around 300 Litres per second and by our calculations the preferable amount was 870 Litres per second.


We don't just consider the combustion requirement for air supply, we also take into account your operating conditions (tropical or hot Vs cooler locations), whether you have wet or dry exhausts, the actual layout of your engine room and of course other components that could be using air and adding to the heat stress of the space.

The New Engine Room Ventilation System

After assessing all the factors that affect your engine room air flow and heating, we recommended the following system for Peter and Suz Nordhavn 43.



The Installation & Testing

Peter has been very glowing in the blog post on his website of how easy it was to install the system, and we are of course very appreciative of Peters comments.


While we don't install any of our equipment ourselves, each item is supplied with full installation instructions and everything you need to complete the installation. Peter installed everything himself, engaging an electricion to complete the wiring for him.


After leaving Sanctuary Cove and some base testing, Peter, Suz and Neon did a 2 and a half day trip to test the results. Without the new fans in an external temperature of 23 degrees celcius, they saw engine room temps of 46 deg C, however after turning the new fans on they had the following results.



  • At half speed the temperature dropped to 40 degrees
  • At Full speed the temperature dropped further to 33 degrees &
  • At three quater speed the temperature sat at a very maintainable 36 degrees.


Long term Peter ended up removing the extra Axial fan he had left on the port side of the engine room with no ill effects.

The Opal Lady
The manual fan speed controllers installed
The intake grille installed
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