can someone tell me what these two hoses/ducts are for?

Aug 7, 2023
239
catalina catalina 320 norwalk
they are immediately behind the engine. Perhaps that is a exhaust and there is a blower somewhere and one is a fresh air intake?
 

Attachments

May 17, 2004
5,683
Beneteau Oceanis 37 Havre de Grace
Those two ducts look like they’re for airflow, possibly with a blower. With a diesel engine that’s primarily to make sure the diesel has enough air to consume, and to help exhaust some heat.

Separate from the ducts I’m quite concerned about the through hull below the prop shaft. That looks like it’s just a plastic nipple screwed into the hull, with no valve at all? Definitely doesn’t look like a proper seacock. If that hose fails as far as I can tell there’s no way to stop the water ingress.
 
  • Like
Likes: ggrizzard
Aug 7, 2023
239
catalina catalina 320 norwalk
Those two ducts look like they’re for airflow, possibly with a blower. With a diesel engine that’s primarily to make sure the diesel has enough air to consume, and to help exhaust some heat.

Separate from the ducts I’m quite concerned about the through hull below the prop shaft. That looks like it’s just a plastic nipple screwed into the hull, with no valve at all? Definitely doesn’t look like a proper seacock. If that hose fails as far as I can tell there’s no way to stop the water ingress.
thanks, it's a Catalina 320. Someone Has to recognize those ducts. I am too old and too claustrophobic to get down there much more and try to figure out where they go. One of them seems to go out the back of the boat. noticed yesterday that the hose was cracked badly where it makes a right angle just as it exits the boat out the transit through a chrome scoop.

it's a 2004 Catalina 320 with original through hulls. I guess it's bad lighting that prevent you from seeing the handles.
 
Sep 24, 2018
3,406
Catalina 30 MKIII Chicago
it's a 2004 Catalina 320 with original through hulls. I guess it's bad lighting that prevent you from seeing the handles.
Handle or not, it looks like plastic. A Groco ball valve, while not a proper seacock, costs around $50. Even that would be better than plastic. Don't underestimate the amount of water that will come in if something breaks
 
  • Like
Likes: Timm R Oday25
Aug 7, 2023
239
catalina catalina 320 norwalk
Handle or not, it looks like plastic. A Groco ball valve, while not a proper seacock, costs around $50. Even that would be better than plastic. Don't underestimate the amount of water that will come in if something breaks
Handle or not, it looks like plastic. A Groco ball valve, while not a proper seacock, costs around $50. Even that would be better than plastic. Don't underestimate the amount of water that will come in if something breaks
catalina might be biggest maker in world??also when winterizing in fall only through hull that gave me trouble was after market brass that last owner put in for heatpump.
 
Sep 24, 2018
3,406
Catalina 30 MKIII Chicago
catalina might be biggest maker in world??also when winterizing in fall only through hull that gave me trouble was after market brass that last owner put in for heatpump.
Was it lubricated every year? My original, 46yo, had no issues with the ball/handle turning. It appears as if the ball only touched plastic and no metal. I replaced it because I saw pitting in the finish which may compromise the seal
 
Jun 8, 2004
2,955
Catalina 320 Dana Point
Ventilation for the engine compartment AKA "bilge blower" on the port side of transom there is an exhaust fan connected to one while the other is a passive intake. There is a switch on the underside of engine instrument pod to turn on/off it is connected to the key switch. If you turn key on, with engine off you will hear the fan if it is functional and switch is on. Even with engine running it is usually the loudest thing you hear.
Note switch labeled "blower" on photo.
1709137675318.png
 
Jun 8, 2004
2,955
Catalina 320 Dana Point
And that is a Forespar Marlon thru hull used on most Catalina's since 1992, that's a LOT of boats.
1709138020556.png
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,146
CAL 35 Cruiser #21 moored EVERETT WA
catalina might be biggest maker in world??
While this might be a true statement, the design of your thruhull/ball valve/hose is not the design intended by the manufacture Forespar, of your marelon ball valve.

Here is the intended design with a hose that is either straight to the ball valve fitting or at a less than 45º angle.
1709139948872.png

Marelon recommends the use of an "Elbow" when the hose to valve connection exceeds 45º. This is to reduce the strain a bent hose that can be moved about while in use from breaking off the straight tailpiece of your valve.

1709140045250.png


Now one of the challenges is a 90º tailpiece will cause some reduction in flow. If that is a critical issue in your installation look for a Full Flow 90º elbow. (I know groco makes them for their "Bronze" valves). I do not think Marelon makes a "Full Flow elbow. So clever sailors increase the diameter of the valve/elbow to get the desired flow.
 

dLj

.
Mar 23, 2017
4,410
Belliure 41 Back in the Chesapeake
Just an observation - the OP was asking about the unknown hoses - now we are fixing his thru-hull... Perhaps a different thread might be in order? There is some great info here but if anyone wanted to find it in the future, might be quite hard to find... Just a thought...

dj
 
  • Like
Likes: Timm R Oday25
Jun 8, 2004
2,955
Catalina 320 Dana Point
they have a little pin with a donut on the end. Does anybody know what they are for?
Yeah, you don't want to futz with that, it's a cap that reveals a screw head that holds the handle on that doubles as a plug when inserted from outside. Don't futz with it while in the water, here's a vid that came up in a You tube search.
 
Aug 7, 2023
239
catalina catalina 320 norwalk
Just an observation - the OP was asking about the unknown hoses - now we are fixing his thru-hull... Perhaps a different thread might be in order? There is some great info here but if anyone wanted to find it in the future, might be quite hard to find... Just a thought...

dj
I just talked to catalina direct they seem to think that the two hoses are exhaust and inlet for engine gases. It seems odd though that they would be right next to each other.
 
Jul 7, 2004
8,492
Hunter 30T Cheney, KS
I just talked to catalina direct they seem to think that the two hoses are exhaust and inlet for engine gases. It seems odd though that they would be right next to each other.
It's not good practice to put supply and exhaust beside each other. Airflow just follows the shortest path and accomplishes nothing :(
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,146
CAL 35 Cruiser #21 moored EVERETT WA
It's not good practice to put supply and exhaust beside each other.
That would be a good suggestion for the Catalina installers on the 320.
 
Aug 7, 2023
239
catalina catalina 320 norwalk
It's not good practice to put supply and exhaust beside each other. Airflow just follows the shortest path and accomplishes nothing :(
I agree but certainly catalina knew what it was doing so those two hoses must be for something else. did you see the picture of them? I will attach it again
 

Attachments