R21 Classic Engine Compartment Heat

[tlkenyon]

This probably applies to all R21's, but my only experience is with the Classic.

On a hot summer day, I was curious as to the amount of heat buildup in the engine box. I took one of those indoor/outdoor thermometers and put the outdoor sensor in the engine box, on top of the fuel tank. After a short time, the engine box temperature rose to 110F and kinda stayed there. After shut-down, the temp rose to 121F and stayed there for what seemed like hours. Since that first test, I have kept the sensor in the engine box and positioned the display so I can see it underway. Pretty much regardless of the weather, the engine box temp rises to over 100F and stays there, going up t 120+ after shut-down. BTW, I have an engine water temp gauge, and it is in the green all the time, so excess engine heating is not a factor.

Has anyone come up with a ventilation solution in addition to the stock vents? I do not really want to move the batteries and fuel tank, as they work pretty well where they are. I am concerned over the heat stress load on the batteries mostly, but also the heat stress load and aging on all the components in the box.

I am thinking of a thermostatically controlled blower, but am not sure where to direct the discharge such that it will be effective, but not pose problems with fugitive engine noise and unwanted heat in the cockpit.


THANKS IN ADVANCE,

TK
Is this a real concern, or am I making a mountain out of a molehill?

 

[SlackwaterJack]

I would vote on mountain out of a molehill...121 deg. isn't really all that hot (check the underhood temp on your car)
You could enlarge the little square engine cover vents but I think that would have little effect and just allow more engine noise (I believe they are there more for engine breathing and not for ventilation anyways). When a diesel engine is running it ingests a large volume of air so those vents are pulling lots of fresh air into the engine enclosure. A blower would be un-neccessary as the heat isn't that bad. I have re-located my fuel tank to the rear compartment but that was to allow better bilge access, not to avoid heat.
If you want to add a blower, you might consider one (on a thermostatic switch) for the pilothouse...Mine was easily 120 deg on Saturday (closed up) and what with all the electronics that some folks have on their boats there could perhaps be some costly neg impact on that over time.

As a frame of reference....I bought my daughter a Mini Cooper and drove it to her in Texas last week (Go Bobcats!). Local temps were between 104 and 107 for the 10 days I was there...I shudder to think what the underhood temps were. I thought I was going to melt standing in the shade... thank goodness there were adequate quantities of ice cold, specially prepared, barley filtered, rocky mountain spring water available.

 

[walldog]

Probably not a big concern. These boats have several years on their configuration and I do not know of any that needed to be vented because of excess heat. I never checked mine during the time I had it, but I did run it in the Texas summer heat and never had a problem with overheating of the engine. My compartment was well insulated for sound which may have helped with not being overheated from the sun or outside temps.

 

[tlkenyon]

Thank you gentlemen, for your informative replies. I will leave the molehill as-is. Just for fun (??) I am gonna put the sensor under the car hood...today it is near 100F....should be interesting. BTW....I carpeted the pilot house sole and also stuffed carpeting beneath the step where the wires, etc enter the pilot house under the doorway. It is a LOT quieter. Any other tips for sound-reduction in the pilot house?