Bildge Blower Hose Routing

[ddrieck]

I restoring an old 1972 18' FiberForm stern drive. When I drug it home all the bildge blower hose was lying in the bildge. I am to the point of running new hose and would like some advice on where to route it. The boat has two intake vents on each side near the transom and two exhaust vents on the transom right above the outdrive with one haveing a 3'' squirrel cage type blower in working order. Do I run a hose from each intake down into the bottom of bildge area and and two running from the bildge to the exhaust vents with one being hooked to the blower? Any thoughts??

 

[airshot]

Re: Bildge Blower Hose Routing

Can't say for sure whether mine is absolutely correct or not, but here goes. On my Islander the exhaust with the blower (sucks out) is the lowest hose in the bilge. The other exhaust hose is almost as low. The intake hoses, one is low and one is high, not to far from the flame arrestor on the carb. It has always been my belief the the powered exhaust should be as low into the bilge as possible to draw the heavier fuel fumes out of the compartment. One high intake and one low intake to help mix the air in the compartment better. Can't say for sure if this is text book or not but the coast gard checked it out and made no comments on it so it must have been OK.

Airshot

 

[ddrieck]

Re: Bildge Blower Hose Routing

Thnaks Airshot.... makes perfect sense now that I think about it.

 

[four winns 214]

Re: Bildge Blower Hose Routing

My one powered bilge exhaust hose draws air from a low point in the bilge as do the two unpowered ones. Both unpowered ventilation hoses that feed air to the bilge underway deliver air to the bottom of the bilge from intakes at the top rear sides of the boat.

 

[smokeonthewater]

Re: Bildge Blower Hose Routing

they shouldn't... if they route to the bottom of the engine they should be (and probably are) exhaust vents

 

[Don S]

Re: Bildge Blower Hose Routing

For the full story.

http://www.uscgboating.org/assets/pdf/downloads/VENTILATION.pdf

 

[airshot]

Re: Bildge Blower Hose Routing

Thanks Don, I wonder if that was written by a lawyer? Typical government wording, they have to go around the block to get across the street.

Airshot

 

[Don S]

Re: Bildge Blower Hose Routing

The reason for that is to explain it in layman terms.
Here is a copy and paste from the format page of the download.

FORMAT
The format of this guideline follows the sequence of requirements in the federal regulation regarding
ventilation.
Each portion of the regulation is recorded first, preceded by the title, FEDERAL LAW, followed by a
discussion which is designed to improve the reader’s understanding of the intent of the regulatory
requirement. Diagrams and tables are included to provide the reader with adequate illustrations of
the subject(s) under discussion.
The discussion, diagrams and tables are followed by a checklist for regulatory compliance titled TO
COMPLY WITH THE LAW. All the items in this section must be answered in the affirmative (YES) if
compliance is to be achieved.

 

[four winns 214]

Re: Bildge Blower Hose Routing

they shouldn't... if they route to the bottom of the engine they should be (and probably are) exhaust vents

The ventilation hoses terminate at the bottom of the engine compartment in the vicinity to where the unpowered exhaust hoses collect. From their length and the fixtures that fasten them, I'm fairly sure they're right where Sea Ray routed them.

 

[smokeonthewater]

Re: Bildge Blower Hose Routing

Regardless of who did or did not want it that way, routing intake air to the lower portion of the engine compartment is a bad idea

the last thing you should do if you have a build up of explosive fumes is to direct a stream of air into the buildup and disperse it throughout the compartment....

Instead, keep it condensed and pull it out of the boat

 

[salty87]

Re: Bildge Blower Hose Routing

I restoring an old 1972 18' FiberForm stern drive. When I drug it home all the bildge blower hose was lying in the bildge. I am to the point of running new hose and would like some advice on where to route it. The boat has two intake vents on each side near the transom and two exhaust vents on the transom right above the outdrive with one haveing a 3'' squirrel cage type blower in working order. Do I run a hose from each intake down into the bottom of bildge area and and two running from the bildge to the exhaust vents with one being hooked to the blower? Any thoughts??

are there no forward vents? i have 1 on either side of the windshield. this is a much better location for drawing air in. the transom area underway has bit of negative air pressure...sort of the station wagon effect.

the rear vents are all exhaust on mine. some are passive and then 1 for the blower exhaust.