Clamshell thru hull

[305kingfisher1954]

I'm installling a 1 1/4'' bronze clamshell thru hull for my livewell and washdown in my 222...Which way should the slots in the clamshell face? Just not sure, I've seen the slots facing foreward.,aft and even sideways. I was thinking if the slots were faced forward it would pressurized the system while running and if the slots were to the aft it would restrict the water flow..so is sideways the way to go?., it looks like shur flow shows it sideways on one of their installation sheets, just not sure...

[wessnapp]

Forward facing.  When you are running, turn off your pump and the pressure will take care of the intake for fresh water for fish.

[gran398]

Forward facing...but I've always heard leave the pump on so the impeller spins at a constant speed, ie, won't burn out prematurely.

[wessnapp]

Interesting - I heard turn it off so it will spin freely and not go against the motor trying to spin at a certain speed.  

POLL???

[gran398]

Interesting - I heard turn it off so it will spin freely and not go against the motor trying to spin at a certain speed.  

POLL???

Yoda? Yoda?

(This is Pete's new name for Seabob)

 

[Blue Agave]

Forward facing...but I've always heard leave the pump on so the impellar spins at a constant speed, ie, won't burn out prematurely.

From the time I get onto the boat to the time I load her boat back on the trailer my livewell pump is on. Regardless if i'm underway or on the hook eating fried chicken.

[Capt. Bob]

Well my pump is a diaphragm type (Shurflo Bait Master) so no impeller is involved.
Doesn't make much sense to run it on the way out or back because boat movement does its job (pumping) thus extending the usable service of the pump.

Obviously, if your not using the well, you wouldn't run the pump but if you have concerns about the inner workings of it, keep the sea cock closed. Problem is, that's kind of a PITA if you use the wash down a lot.

Solution.
Get a diaphragm pump and pay less attention to the impeller bushing that doesn't exist.

[Blue Agave]

Doesn't make much sense to run it on the way out or back because boat movement does its job (pumping) thus extending the usable service of the pump.

Hogwash, my boat has been in service for 11+ years and the livewell is on all the time, it's only on its second pump.

Well my pump is a diaphragm type (Shurflo Bait Master) so no impeller is involved.

Solution.
Get a diaphragm pump and pay less attention to the impeller bushing that doesn't exist.

I can't tell you how many of those pumps I have replace in boats down at the shop. They go bad all the time.

[Capt. Bob]

Doesn't make much sense to run it on the way out or back because boat movement does its job (pumping) thus extending the usable service of the pump.

Hogwash, my boat has been in service for 11+ years and the livewell is on all the time, it's only on its second pump.

Well while you're washin' your hog, explain how you have determined that it would not have lasted longer. You might still be using the same pump for all you know. Every mechanical device has a lifetime.

Well my pump is a diaphragm type (Shurflo Bait Master) so no impeller is involved.

Solution.
Get a diaphragm pump and pay less attention to the impeller bushing that doesn't exist.

I can't tell you how many of those pumps I have replace in boats down at the shop. They go bad all the time.

Can't argue with that. You have actually seen the failure and replace them but let's look at the original question and how we got here.

Member asked about clam shell pickup orientation. Next a member recommended a position and added the little snippet about running the live well pump continuously. Another member stated he had heard the opposite. It appeared to me that both members were discussing a type of live well pump that was impeller driven and was mounted in the inlet line upstream of the clam shell. Now unless the original poster is going to run two separate pumps (and perhaps he is, it was never stated) then my experience with running a single diaphragm has merit based on the fact that you don't need to worry about line pressure shortening the life of the pump.

Lastly, I don't use my well on every trip and not carrying an additional 130lbs of seawater seems like a good idea but if I did, I still don't need to run it coming and going. I'm spending enough in fuel not to get the benefit of some free water pressure.

You never stated where your pump was located or the type. Maybe you're on to something about running a diaphragm type continuously.  

[wessnapp]

Wow - that got heated.  I almost thought I was on the THT for a minute.  

I did post the "poll" on the THT - see what they said..... http://www.thehulltruth.com/boating-forum/409453-pump-off-when-running-clamshell-intake.html

I think it is fair to say, answering the original question - the vent faces forward.

[gran398]

For baitwell applications, an impeller style pump is used most often because:

a. Cost. They are inexpensive at 19-30 bucks vs. 150 bucks

b. Current drain. 1 amp vs. 6 amps (rough numbers)

c. Noise. The impeller is virtually silent, the diaphragm loud.

d. Volume. Max volume on a diaphragm pump 360 gph. That is why they are usually advertised at gpm.

For baitwell/washdown applications (washdown being the operative word) a diaphragm pump is preferred because:

a. Self-priming, usually advertised to a 12 foot head. It can suck all of the air it wants....it will always self-prime. Not true with the little pump.

b. Maintains constant line pressure, just like a well pump...or with air, a compressor.

c. Longer life, more reliable

The ideal set up would be one of each, the little pump at the seacock with two outlets, one to the well and the other to the big pump. The big pump could also easily be plumbed as a livewell backup.

Anyway...face the pickup forward

Wes, that wern't heated, they was jus a talkin' about their hogs an all

[Capt. Bob]

Wow - that got heated.  I almost thought I was on the THT for a minute.  

Nah,
Just good ol' boys talking about hogwashin'  

[gran398]

[slvrlng]

Okay, so my question now is : Does the diaphragm pump put out enough water to wash a hog?  

[wessnapp]

Wait - what kind of hog?
- Feral?
- Rooter?
- Russian?