Hi,
i am replacing my inline engine raw water filter with a new "basket" style unit.
The in line unit was below the water line, which was a bit of a hastle. Even if I shut the through hull before cleaning water goes everywhere when the pipes drain. Forget to shut the through hull and water goes everywhere until my rather slow brain kicks into gear and works out what has happened.
So, at what height should the filter be located? I am thinking of locating with the lid about 20 mm above the water line. Logic being that I want to minimise the water released when opening, but do not want it high enough to mean that the pipes drain and fill with air when opened for cleaning.
Does this make sense?
thanks
I would mount it with the top of the strainer about 5 or 10 mm below the waterline.
Select to expand quoteLMY said..
Hi,
i am replacing my inline engine raw water filter with a new "basket" style unit.
The in line unit was below the water line, which was a bit of a hastle. Even if I shut the through hull before cleaning water goes everywhere when the pipes drain. Forget to shut the through hull and water goes everywhere until my rather slow brain kicks into gear and works out what has happened.
So, at what height should the filter be located? I am thinking of locating with the lid about 20 mm above the water line. Logic being that I want to minimise the water released when opening, but do not want it high enough to mean that the pipes drain and fill with air when opened for cleaning.
Does this make sense?
thanks
Usually the lid height is about the same as the top of the engine. Quick check in a Volvo installation manual [all engines]and they state 3 metres above the water line as the maximum height due to the limitations of the pump. I would instal it where its easy to access.
Not to contradict anyone, but to my knowledge the experts recommend the strainer to be a b o v e the water line with a non return valve.
My first hand experience is that, insurance requires the use of approved marine grade hoses and double clamps under the water line.
Ps: The hoses on the picture are the ones the insurance people did not like. Since replaced.
The rhs. hose has the non return valve stopping the pump and impeller chamber to drain dry - because this strainer is above the water line, it might drain dry - and possibly get damaged when you press the starter. It might not pick up the raw water at once.
If the strainer is under the water line, the non return valve is not needed but you risk flooding they say.
One thing to think about also is your hose size meaning find a strainer with the correct hose barb size the is the same as the seacock
My original inlet hose had a reducer fitted hidden under the engine sump
Clamped but rusted through could have sank
As long as your impeller is below the water line a non return valve is not needed.
All, thanks for your ideas.
Sirgallivant,
thanks for for the information re your insurance companies requirements. I will read my policy and see what it says.
i can understand the logic of placing the filter above the water line as this eliminates one potential failure below the water line. However, if you then add a non return valve, and presumably below the water line, you are kind of back where you started. You have also added a potential failure to the water cooling if the non return valve failed or blocked. I do not think I have space to locate above the water line, but will have a look.
Interesting comment re the alowable hose though, I have been gradually changing out 25 year hoses that are fibre reinforced clear poly. They have all hardened, but have no sign of failure. I have been using similar hose to that in your picture. Do you know what they mean by "approved grade marine hose" is this to an Australian Standard? I suppose that I can only really check that the hose is to a standard, with a sensible pressure rating.
I have show this before but it was part of the raw water cooling sea cock to sea strainer it is a reducer from inch to 3/4 that was hidden under the engine sump motors 6 hours or more like this . Show just goes to show even after a survey and when first buying your boat check as much as you can yourself.
I can see every inch of the raw water inlet now
My water line would be 3/4 up the water pump housing. I still think I would need to turn the sea cock off before lifting the boat out on the hard and turn it back on before starting the motor.
No need to turn off the seacock. The positive seawater pump will draw up the water. About 3 metres is the limit. The impeller will have enough moisture and if you have just had it apart a little grease is all that's needed.
Select to expand quoteLMY said..
All, thanks for your ideas.
Sirgallivant,
thanks for for the information re your insurance companies requirements. I will read my policy and see what it says.
i can understand the logic of placing the filter above the water line as this eliminates one potential failure below the water line. However, if you then add a non return valve, and presumably below the water line, you are kind of back where you started. You have also added a potential failure to the water cooling if the non return valve failed or blocked. I do not think I have space to locate above the water line, but will have a look.
Interesting comment re the alowable hose though, I have been gradually changing out 25 year hoses that are fibre reinforced clear poly. They have all hardened, but have no sign of failure. I have been using similar hose to that in your picture. Do you know what they mean by "approved grade marine hose" is this to an Australian Standard? I suppose that I can only really check that the hose is to a standard, with a sensible pressure rating.
Clear plastic reinforced hoses are banned for vessels in NSW survey in engine rooms. Use rubber from a decent supply shop. It's no dearer than the plastic crap.
The plastic hardens and eventually the clips can not be tightened further. When the clips break and there is only a single clip instead of the mandatory two, you have a leak.
When the insurance-surveyor saw those hoses on the pic. he straight away said, those must come off!
That happened in the land of the Queen, though.
Club Marine got the same rules in Oz, l presume.
Those plastic hoses are crappy, for sure. Good for galley or toilet water but that is all.
My deck water-filler had a connector hose to the tank and it was so much hardened, it took serious effort to get it off. It had no flex left in it at all, when l bent it, it snapped no unlike glass.
Got a rule, when leaving the boat for more than a minute, l turn all sea cocks off, anyway !
I'm not sure if it was a good idea not
I used and bought some silicone hose from work for my inlet side cooling system
As long as I don't get any oil on that hose I think it will be fine
I found the same thing LMY when researching the hose, I had the crappy clear plastic reinforced hose on my boat so I removed it and ended up replacing it with the crappy clear plastic reinforced hose because I felt it was a better hose than allot of rubber hoses. I would be happy just to replace them every year when checking out the fittings anyway.
Used to deal with this company my self in Business
www.totalrubber.com.au/default/technical_information
For my engine cooling water lines from sea cock to wet exhaust elbow discharge I am using SAE half inch heater hose. It, like any other hose, works fine as long as you do not put too tight a bend in it.
Insurance companies insure cars and trucks using SAE rated hoses so I can't see what the problem is. You replace the heater and radiator hoses on your car on a regular planned maintenance basis. Why would you not do it on your boat??
The suction pulled by a yacht engine cooling water pump will never be enough to collapse SAE rated hose.
What is the obsession with clear reinforced hose?? Are we going to sit there and watch it to see what goes through it????
I am not a fan of clear reinforced plastic hose or any plastic hose but it does have some use aboard a yacht such as water tank filler lines but certainly not around the engine or bilge.
Select to expand quoteHG02 said..
Used to deal with this company my self in Business
www.totalrubber.com.au/default/technical_information
Good link. I live in a country town and fortunately we have a business here that stocks all that stuff.
I cannot see the point of clear reinforced hose at all. Not sure I would want to drink water that has passed through a plastic pipe that allows sunlight through. Food safe plastic pipe does not allow sunlight through it for a reason.
Select to expand quoteRamona said..
Good link. I live in a country town and fortunately we have a business here that stocks all that stuff.
If you are thinking of that place out at Flinders you may want to go and have a look at it now. Paul recently retired and sold the business to a Yank conglomerate who decided that they didn't need most of what Paul had as they said it didn't represent their "core line of business".
Why buy a business if you don't want to sell the products that made that business what it is? ...weird ... but that's Yanks for ya.
I've seen Dunlop do that to a retailer just so they controlled the market price
LC
I've seen Dunlop do that just to control the market price bough a business and sold everything off
Select to expand quoteLooseChange said..Ramona said..
Good link. I live in a country town and fortunately we have a business here that stocks all that stuff.
If you are thinking of that place out at Flinders you may want to go and have a look at it now. Paul recently retired and sold the business to a Yank conglomerate who decided that they didn't need most of what Paul had as they said it didn't represent their "core line of business".
Why buy a business if you don't want to sell the products that made that business what it is? ...weird ... but that's Yanks for ya.
Yes I was there during the week. I was shocked at the changes too. They seem to want to compete with Bunnings!
My only warning word to this otherwise meaningful conversation, please, do yourself a favor, check out your insurance policy, make sure your hoses below the water line correspond to insurance requirements!
It would be foolish to have a claim rejected over twenty or fifty bucks worth of hose.
You could do nothing when at the salvage of your boat they find an inappropriate hose or sea cock or whatever else, for that matter. They are going to reject your claim over a trifle.
I heard claims rejected over the re-use of a cotter pin.
The rigging came down because of a lost clevis pin which came undone because the loss of a cotter pin.(if you use cotter rings though, the can go to hell!)
When they checked the rest of the rigging, they realised the frequent re-use of cotter pins on the rigging. It is really a twenty cent item which was the weakest link in the chain. Tragic.
I found Vetus - Maxwell in Ingleburn can supply such hoses as well as other marine products.
The representative is:
Fenquins 2/27 Williamson rd Ingleburn NSW 2565
02-96055522
Ok,
I have had a look at my (NRMA) policy. I can find no specific reference to hosing. There are however, two clauses that may be relevant. Claims can be rejected if the damage arrises from "faulty design or workmanship" OR "ÿou have modified the boat from manufacturers specifications".
When I was planning the filter installation I changed out "crappy plastic hose"and without a lot of thought used plastic hose. Note that the plastic hose was probably original, and over 25 years old. It seemed reasonable to me to replace something that had lasted that long with the same material. If I use rubber hose and that fails I have modified the boat so if it sinks the the insurance company could possibly argue that I have modified the boat and deny cover. On the other hand there seems to be a body of opinion that the plastic hose is faulty workmanship so this argument could be used to deny cover. As always with insurance they have plenty of options to deny cover if they want to.
It is probably best if the boat does not sink, avoiding the need to claim. To be certain that I am doing the best for the boat I have looked at the specs for plastic and rubber hose. From the specifications I conclude that plastic hose matches or betters many rubber hoses on the basis of pressure rating, temperature rating and bend radius. Bend radius being important in my particular installation which is tight for space with difficult access. I cannot find specifications that relate to resistance to oil, fuel, abrasion, life expectency.
However, there seem to be many with more experience than me who are using the rubber hose so I will take that advice and change out the plastic. Got to say I will not panic though and see little risk in the short term so will spend some time to find a rubber hose that matches the specifications of the plastic hose.
Select to expand quoteHG02 said..
I have show this before but it was part of the raw water cooling sea cock to sea strainer it is a reducer from inch to 3/4 that was hidden under the engine sump motors 6 hours or more like this . Show just goes to show even after a survey and when first buying your boat check as much as you can yourself.
I can see every inch of the raw water inlet now
My water line would be 3/4 up the water pump housing. I still think I would need to turn the sea cock off before lifting the boat out on the hard and turn it back on before starting the motor.
After thinking about what I said about the silicon hose I now realize this hose has a outer cover silicon on the inside so in reality oil will never effect it.
To me it was a good choice its used on most trucks cooling systems these days as it out last anything else
