Is a bilge pump possible for a 1985 Invader V170?

[fhhuber]

It all depends on what size leak you want the pump to be able to keep up with...

750 gph will probably keep up with most rain conditions where you'd be willing to stay out on the lake. Also it would probably keep up with random splashes into the boat from crossing wakes and it would get rid of water that came over the transom when you slowed down too fast. But its probably not going to keep up with a 3/4 inch dia hole in the hull (common drain plug)

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Found the formula for figuring the flow:


You can calculate the flooding rate of any size hole:

Q = 20 x d x square-root of h
Q = flooding rate in gpm
d = diameter of hole in inches
h = depth of hole underwater in feet

Common 3/4 inch drain plug comes out to just over 1000 gph at 1 ft depth.

 

[Watermann]

A 750 should suffice for any normal leaks, rain and such. I wouldn't worry too much about a 750 being too small for a 17' boat that doesn't have one at all and has yet to sink. :lol:

 

[GA_Boater]

I am also surprised a 1985 model boat wouldn't have a bilge pump from the factory. Are there any corrugated looking hoses about an inch or a little more, usually white but sometimes black? They would be under the splashwell and going to either upper side. Are there any ports on either side of the boat with an end that looks like this white thing just below the rubrail?

 

[fhhuber]

Sometimes above the rub rail... Always above the water line + a margin for keeping it above most waves with the boat floating at anchor.

 

[fostersds]

That would be a negative. I have not seen any port that resembles the above picture at all. I was curious why there wasn't a pump already but I wasn't aware when they became standard issue.
I did think of another issue or question last night as I was contemplating installing the pump. When I fasten the pump down to the hull, do I have to worry about going thru the hull? I was probably going to use 3/4" or 1' screws.

 

[GA_Boater]

No screws or you have a good chance of unintentional pump testing. :blue:

Once you find a spot for the pump, use a bed of 3M 5200 adhesive to mount the pump base. 5200 comes in 2 flavors - Fast or slow cure. Slow cure takes a week to cure, whereas the fast is 24 hours.

After allowing the curing time, put the pump cartridge (motor) in the base and secure it, usually a twist lock. Finish the wiring and plumbing and test it. No water needed, just flip the switch to hear the pump run.

Hint - Install the hose on the pump before putting pump in the base. You have less chance of breaking the pump base to hull bond if the 5200 is not fully cured.

 

[fostersds]

OK. That is good to know. Thank you for the advice and assistance.

 

[Old Ironmaker]

For what ever pump you do get make sure it is an automatic pump not only manual select. Most of the aftermarket pumps we have here in Canada show in litres per minute then I have to convert that to gallons so I know what it is!!!. The diameter of the discharge line will determine what the maximum gallons can be pumped out regardless of the capacity of the pump. I'll leave that for someone else to calculate. Mine is about 10 gallons per minute when I held a bucket under the discharge line. It wouldn't keep up though the one time I forgot the plug. OOps.

But make sure you get an automatic pump. It has a flapper that lifts when the water level reaches the height of the pump and automatically comes on. If you do take on water for any reason it will pump that water out when you aren't there, great peace of mind knowing that. Generally these bilge pumps do not get 100% of the water in the hull out, that's why a drain plug is still a must have. And be sure to keep the bilge pump and flapper clean. I just give mine a spray of Spray 9 and get my wife that has long arms to give it a wipe clean. If and when you do install one if you do make sure it's where you can reach it easily. Easier said than done. I swear some of these boat designers never owned or worked on a boat. Like many autos they engineer them so you are bound to take them into the dealer or Marina for service at many $$$ a pop.

 

[GA_Boater]

I have a flapper float switch on the 2nd pump wired directly to the battery, so totally auto. The main pump is on a dash switch. When I pull out the portable fuel tanks for filling, I reach back and flip the float to make sure it's working. Some boats aren't so accessible.

 

[fostersds]

Ok. Thanks. Is it possible to have the same pump hooked up to a switch and a flapper? The reason I ask is I have seen a toggle switch for Johnson that has a auto or manual setting.

 

[GA_Boater]

Ok. Thanks. Is it possible to have the same pump hooked up to a switch and a flapper? The reason I ask is I have seen a toggle switch for Johnson that has a auto or manual setting.

That's why the switch is labeled Auto/Manual. The pump needs to have a built in float switch or an external float switch like we've been talking about. The dash switch is wired in parallel with the float switch so either automatic or manual activation kicks it on. New pumps usually have wiring instructions and if your new one doesn't, pretty sure we can help.

 

[fostersds]

That is why I like this forum. I know that a novice like myself can always get help here.

 

[GA_Boater]

That is why I like this forum. I know that a novice like myself can always get help here.

Hey, hey - I said pretty sure we could help. Didn't say we would. :lol:

BTW - I like an external float over an integral switch. When the switch goes bad or the pump itself. you only need to replace a cheaper part. Otherwise it's buy a complete new set up.