On our sailing designs we have typically been able to avoid air conditioning by engineering good air flow at anchor. But with the FPBs the heat load on all of the glass makes air conditioning a necessity. Back aboard now in Fort Lauderdale, with the sun directly overhead, and temperatures in the afternoon at 88/90F (31/32C), we are putting this to use, and thought a few details might be of interest.
To begin with, we have just two 16,000 BTU units in the great room, a 12,00 BTU unit forward, and a 10,000 BTU system aft. All four compressors are in the basement, with the salon and forward cabin units drawing their return air from the basement (which is much quieter but less efficient than getting their return from the living areas).
The norm would be much larger compressors, in particular for the great room, which means a much bigger genset, and having to run the genset under way. Making the smaller compressors work involves reducing the heat load on hatches and windows.
As you can see in the photo, there are awnings over the foredeck and great room hatches, and over the side windows. In addition, the windows have a 3M film which reduces heat load from infra red by as much as 50%.eSo how does this work on a windless canal in Fort Lauderdale? With the aforementioned 88F/31C ambient, it takes about an hour to drop the great room temperature 10F/6C, and another hour for an additional 5F/3C. The forward and aft staterooms cool much quicker.
At anchor, we rarely use air con if there is any breeze. If the breeze dies, or the bugs come calling in the evening, we close the boat up, run the air for a couple of hours, and then shut down at bedtime. WIthout sun load we stay cool until morning.
Posted by Steve Dashew (April 14, 2011)
April 14th, 2011 at 11:01 pm
Steve, have you used tinted glass as well as the 3M coating or could the 3M coating be avoided if tinted glass were used?.. tks
April 15th, 2011 at 4:43 am
Howdy Stephen:
Tints or UV protection are not available in the thick structural glass we use. The 3M film also reduces UV A and B by 99% as well as helping with glare at night. It is also simple to change should a different set of characteristics be desired.
April 14th, 2011 at 11:18 pm
Hi Steve/ Linda – glad to see you came back onboard. Looking fwd to upcoming posts. Curiosity: when you stay with Windhorse on marinas for a while, do you hook up to shore power? What about water? (Not familiar with watermakers – i was wondering whether they still work properly on “suspicious waters”, like the ones found in marinas).
Best Rgds, Alex
April 15th, 2011 at 4:48 am
Hi Alex:
If we are in the marina for a couple of days we won’t bother with shorepower, unless we are using the air conditioning. Fresh water is never connected to shore directly due to the flooding risk should there be a leak in the domestic plumbing on the boat. Although we have an oil/water separator on the watermaker we do not run the watermaker in harbpr.
April 15th, 2011 at 7:02 am
Steve, Do you put the 3M film on the forward facing windows as well?. Any impact on night vision? tks
April 17th, 2011 at 5:22 am
Yes, Stephen, 3M film on the forward windows as well:
Most classification rules will not allow this, but the light reduction is so small it does not seem to impede our night vision. And in difficult nav situations we stand watch from the open flying bridge.
January 6th, 2013 at 7:30 am
Steve,
Have any owners installed some sort of interior window dressings to reduce light and provide more privacy? Something like a Hunter-Douglas Silhouette, either manually or electrically controlled would seem to be just the ticket for warm climates and marinas.
January 6th, 2013 at 2:19 pm
We fit manually operated window shades as standard. Type depends on owner preference for ambient light. Our own experience is that anything other than black out lets in too much light.