Clear reinforced hose for raw water?

[hlev00]

I am going to replace my raw water hoses. I was looking at Trident clear reinforced PVC. It says okay for liquid suction lines. My motivation is to be able to see if there is blockage inside the hose without disconnecting it.

Is the raw water circuit - seacock to input of pump - a safe application for this or another clear reinforced hose?

Is it as likely to get covered in gunk on the inside from sitting, ultimately preventing me from seeing inside anyway?

Thanks,
Harry

[unbusted67]

Originally Posted by hlev00

I am going to replace my raw water hoses. I was looking at Trident clear reinforced PVC. It says okay for liquid suction lines. My motivation is to be able to see if there is blockage inside the hose without disconnecting it.

Is the raw water circuit - seacock to input of pump - a safe application for this or another clear reinforced hose?

Is it as likely to get covered in gunk on the inside from sitting, ultimately preventing me from seeing inside anyway?

Thanks,
Harry

The boat I run has had a few issues with blockages so we put in a water flow sensor, alarm, and an 18” section of clear fresh water hose right before the water pump on the engine. I think that’s a safer bet than doing the entire length in fresh water hose which doesn’t have the structure to support continuous suction. I’m not a mechanic or anything but those are my two bits.

[Cheechako]

Usually you want a wire reinforced hose for any hose runs that potentially have a vacuum in them. ie: "Before the pump"
That reinforced clear PVC is pretty stiff though and will probably work .... until there is an issue! IF you get a plastic bag on your hull inlet fitting, will the hose collapse? Maybe ....but it will come back when the vacuum is released... Also, on many boats that short hose would be under the water line, so does it ever have a vacuum in it, or positive pressure?

[phorvati]

Originally Posted by hlev00

I am going to replace my raw water hoses. I was looking at Trident clear reinforced PVC. It says okay for liquid suction lines. My motivation is to be able to see if there is blockage inside the hose without disconnecting it.

Is the raw water circuit - seacock to input of pump - a safe application for this or another clear reinforced hose?

Is it as likely to get covered in gunk on the inside from sitting, ultimately preventing me from seeing inside anyway?

Thanks,
Harry

Green/grey film will form on the inside. Raw water strainer is a better place to keep clean and use for visual inspection. I would get marine hard wall water hose rated for the purpose.

[nuku34]

Re water flow alarms in the raw water intake line:
They tend to be quite expensive and involve moving parts (usually a pivoted vane) which can stick open.
A much cheaper and viable option is this:
Assuming you have a wet exhaust elbow bolted to your exhaust manifold, you will have sea water being injected into that elbow to cool the exhaust gases before they go into your rubber exhaust hose. If the sea water intake is blocked or the sea water pump isn't working (bad impeller), sea water will stop being injected into the elbow, and the elbow will get HOT VERY quickly.
If you attach a simple on-off temperature sensitive switch (normally open) to the outside of the elbow just after the water injection point, and that sensor has its own very loud alarm and bright red LED on the engine panel, you will know within a few seconds that your raw water flow is interrupted.
My switch closes at 70 degrees C and is held on with a modified hose clamp and heat transfer grease that helps the heat to transfer to the sensor. The sensor costs about NZ$7.00, alarm buzzer and led light about NZ$10.

[rwidman]

You are talking about raw water to the engine, right? Clear hose will not stay clear for long. And it's not safe for below the waterline use.

Buy hose that is made for use below the waterline and install it properly. This is not a good place to try to save a buck or invent something new.

[Greatest Lakes]

If it's the wire reinforced hose, you should be fine, don't trust the nylon thread stuff. Nylon hose in general tends to cloud, stain, and absorb all kinds of stuff though, most will advise against it. I have always used the marine hardwall reinforced hose below the waterline. Use a strainer, amazon sells some plastic ones with clear lids, but the plastic lids crack after a while and you can start sucking air, or worse, flood. Perko is expensive, but way cheaper than the boat, but they are effective and trustworthy. Listening to the water getting burped out of your exhaust is the last line of defense. Nuku34 has a good idea about the temperature monitor.

[fourlyons]

Originally Posted by nuku34

Re water flow alarms in the raw water intake line:
They tend to be quite expensive and involve moving parts (usually a pivoted vane) which can stick open.
A much cheaper and viable option is this:
Assuming you have a wet exhaust elbow bolted to your exhaust manifold, you will have sea water being injected into that elbow to cool the exhaust gases before they go into your rubber exhaust hose. If the sea water intake is blocked or the sea water pump isn't working (bad impeller), sea water will stop being injected into the elbow, and the elbow will get HOT VERY quickly.
If you attach a simple on-off temperature sensitive switch (normally open) to the outside of the elbow just after the water injection point, and that sensor has its own very loud alarm and bright red LED on the engine panel, you will know within a few seconds that your raw water flow is interrupted.
My switch closes at 70 degrees C and is held on with a modified hose clamp and heat transfer grease that helps the heat to transfer to the sensor. The sensor costs about NZ$7.00, alarm buzzer and led light about NZ$10.

This^^^
I did this and it saved my butt when the shaft seal on my raw water pump went bad and lost it's prime. The hose heated up and the alarm went off so fast no damage was done. The temp sensors are so cheap I wired up two of them, just for redundancy.

[David Mathis]

The 9kw generator has the hose you described in use between the strainer and raw water pump for over ten years with no issues. It has stayed clear and flexible.

[Scrimshaw4]

I replaced the raw water inlet hose for my refrigerator circulation pump with DAVCO clear wire renforced hose that I purchased on Amazon. It works great and is worth checking out. JMHO

[pcmm]

Originally Posted by fourlyons

This^^^
I did this and it saved my butt when the shaft seal on my raw water pump went bad and lost it's prime. The hose heated up and the alarm went off so fast no damage was done. The temp sensors are so cheap I wired up two of them, just for redundancy.

Even simpler solution for me for this is to get the Vetus anti siphon loop. It has no valve in it, just a hose to a small thruhull (included) I have mine plumbed to the outside of the cockpit coaming. When everything is good and I'm at cruising RPM there is a constant stream of water (pee'ing) as soon as you loose 1 vane on the raw water impeller it doesn't have enough pressure to continue a constant pee'ing, becomes more like an old man with prostate issues!!. Save'd me a few times before the engine even got to the point of over heating!

[kayakerChuck]

Last week, I winterized a boat for a friend. This is the raw water intake hose that I took off of the thru hull. I did not cut it- this is how I found it. I'm replacing it with proper wire reinforced hose suitable for use below the waterline. If we look closely, it was cracked on the important side of the hose clamp. (Or, possibly cut by whoever was there before me- the "premier" diesel shop in the area.)

[IMG][/IMG]

[fourlyons]

Originally Posted by pcmm

Even simpler solution for me for this is to get the Vetus anti siphon loop. It has no valve in it, just a hose to a small thruhull (included) I have mine plumbed to the outside of the cockpit coaming. When everything is good and I'm at cruising RPM there is a constant stream of water (pee'ing) as soon as you loose 1 vane on the raw water impeller it doesn't have enough pressure to continue a constant pee'ing, becomes more like an old man with prostate issues!!. Save'd me a few times before the engine even got to the point of over heating!

Yes, the pee stream works too, but not as well.

You have to be checking it regularly. The alarm works whether you watch it or not, and at times there can be a lot of other things happening. Also, the alarm goes off long before the engine overheats, if you lose the water injection that exhaust hose heats up fast.

[unbusted67]

Originally Posted by nuku34

Re water flow alarms in the raw water intake line:
They tend to be quite expensive and involve moving parts (usually a pivoted vane) which can stick open.
A much cheaper and viable option is this:
Assuming you have a wet exhaust elbow bolted to your exhaust manifold, you will have sea water being injected into that elbow to cool the exhaust gases before they go into your rubber exhaust hose. If the sea water intake is blocked or the sea water pump isn't working (bad impeller), sea water will stop being injected into the elbow, and the elbow will get HOT VERY quickly.
If you attach a simple on-off temperature sensitive switch (normally open) to the outside of the elbow just after the water injection point, and that sensor has its own very loud alarm and bright red LED on the engine panel, you will know within a few seconds that your raw water flow is interrupted.
My switch closes at 70 degrees C and is held on with a modified hose clamp and heat transfer grease that helps the heat to transfer to the sensor. The sensor costs about NZ$7.00, alarm buzzer and led light about NZ$10.

Yup, we've got that too.

[sinnerman]

On my boat, I use the trident white/clear reinforced PVC hose on the sink drains and toilet flush water inlet.

I use the black with green stripe wire reinforced hose (MPI or Trident) on the engine raw water intake and the air con water pump intake.

I can see no problem using the Trident clear/ white reinforced hose for sink drains, or the toilet inlet below the water line, if you close the thru-hull valves (which you should) whenever leaving the boat unattended.

I would not use it on suction lines, especially the cooling water">engine cooling water inlet as it is a critical piece of hose whose failure could wipe out the engine.

my two cents

cheers