Engine rooms ventilation and cool down

[MVCaprice]

I think whatever you do will be fine as long as you have a negative pressure setup. Blowing air in will create a positive pressure situation where you are forcing some air underneath the floorboards forward and aft. After looking at this on our boat my gut feeling was that it's probably not sealed enough to do that without a little bit of work.

If I was going to open up the checkbook for this I would probably drop in a fan controller (http://www.deltatsystems.com/dtsp-T4...ol_System.aspx ) as well as a couple large radial fans such as http://www.deltatsystems.com/dtsp-Re...1to30inch.aspx .

I also thing the demisters would be another good option: http://www.deltatsystems.com/dtsp-Mo...liminator.aspx . You can get the demisters with fans so that may be another alternative.

[Pascal]

Forced ventilation into the engine room is used on many newer boats. The 84 Lazzara i run (2009 vintage) has two big 240 blowers pulling air from the side decks into the ER. They are controlled by frequency drives and even have an atmospheric pressure sensor to keep the ER pressurized. The higher the RPM the faster they run to keep up with engine demand. A little too fancy for my ole hatt But after a run if I manually increase blower speed, the ER cools much quicker

On the hatt, with a reasonable blower size the ER can't get pressurized at the openings on the hull sides are pretty large. In any case I intend to seal as much of the holes and penetrations as possible at the end of the project

[Tim Powell]

FOR WHAT IT IS WORTH.
My 52 c draws air from right and left of the tackle lockers. I changed it all. I put tom Slane vents in the side and put two 24volt flush fans inside the engine room. They pull air from the engine room

Air comes in from the side vents and pulled out the stern by the two fans. The fans are on both thermostat and manual control. The fans are loud at the dock, They pull a lot of air and will bring the er room down quite a lot.
the fans look like radiator fans and are enclosed in a plastic case the fit is very neat inside the er room. I took out the dinkey blowers and nasty black hose, The fans are hooked to the old blower switches . Workes well. when the er room is hot it shure makes it nice but you gotta ware ear plugs
https://www.fisheriessupply.com/delt...tion-protected.

[northshoreone]

I talked to delta systems last year about just this topic. Based on the engine room size of my 70 their quote for a system was just shy of $1,800, which included the control box, 4 fans two blowing in and two blowing out. That was parts only 24 volts system. It's still on my list to do at some point.