engine bay blower ducting question on a boat project

[skinny1965]

ok working on old hammond boat about a 78 has a v8 in it. before I got it someone has pulled and broke most of the duct hose . its so bad that I cant tell how it was hooked up the blower motor was sitting on floor .

so there is 4 ports (holes) enter engine bay area, should i hook up 2 to the blower or just one and allow the others to be fresh air draw


not sure best way last thing I need/want is to have issue because engine bay is not evacuated
any pointers or directions would be great

 

[Grub54891]

Look at the louvers on the side of the boat, one should have them facing forward and one should be facing aft. The blower hooks to the aft facing one. It should be run down to the lowest spot in the bilge you can get it, with at least one blower in the line. There should be no "droops" or low spots in the hose to collect and hold water. Also not so low in the bilge to get under water and plug it. The forward facing vent gets installed so the hose comes in up higher, as fumes sink low in the bilge and it'll allow the best air movement. The blower side exhausts the fumes overboard. You can hook up all 4 hoses if you want. depends on the size of the boat, mines a 17 foot and only needs one in and one out. When under way, the blower is off as the natural movement past the vents keeps the air moving. Always run the blower when done fueling or when idling under slow conditions. Hope this helps.

 

[skinny1965]

thanks a ton

 

[Scott Danforth]

New hose is cheap

 

[JoLin]

I replaced my torn-up vent hose with 'Flex-Drain' corrugated poly pipe and end fittings from Home Depot 2 seasons ago. MUCH tougher than the stuff they sell for boats, and cheaper too. You can bend it to where you want it to lay and it keeps its shape

 

[airshot]

I have had to replace mine in the past as well, you are correct on the cheap flimsy material that you get from "marine" stores. I used a flexible duct hose I got online for a vacuum system, much heavier than marine and less cost. Just check the blower diameter to be sure you order the correct diameter hose and then use SS hose clamps to attach. I use a small block of plastic scrap attached to the low end of the hose to keep it low in the bilge as it wants to coil up short without a small weight on the end. My boat has two intake and two exhaust vents, so the lowest hose in on the blower to exhaust and I added another hose to an intake vent and ran it low on the opposite side of the engine compartment to help push any fumes around to be sucked up by the blower. Our rule is...when the boat is launched the first thing is the blower comes on, the outdrive is lowered, a quick check of all safety gear and electronics hooked (depth finder), by this time the blower has had its 5 minutes plus time to run the start her up. Need to get into a routine or you will forget!!