Small boat bilge pump

[RogerFoxTerrier]

Our FoxTerrier 22 is quite small, and has no bilge, just an epoxied sole. But I'd still like an electric pump and the Rule Mate with electronic sensors look the way to go.

Can I Tee the output into the sink drain hose? If not, would an output hose run of about 6 - 7 feet to a hull fitting in the transom be too long? or should I try to exit the hull sooner?

Ta

 

[LittleSister]

I would not T it into the sink drain. You could risk bilge water coming up into the sink, and a friend once had panic-inducing water ingress which took a long time to discover was the result of the sink drain being blocked and hence not performing as the anti-syphon it usually did .

Why do you need to run it to the transom for a drain (if the deepest part of your bilge is not there)? The long run will reduce the capacity of the pump. Why not put a thru-hull just above the waterline in the side of the hull, or even in the bottom of the hull, with a 'swan neck' in the hose taking it well above the heeled waterline on its way there? (Note that the heeled waterline is lower the nearer the centreline of the boat you get than it is at the sides. Though the layout of a small boat usually makes it difficult to achieve a unobtrusive high swan neck on the centreline, the further you can get it from the outer side edges, the more effective it is, or the less height needed for the same effectiveness.)

 

[RogerFoxTerrier]

I would not T it into the sink drain. You could risk bilge water coming up into the sink, and a friend once had panic-inducing water ingress which took a long time to discover was the result of the sink drain being blocked and hence not performing as the anti-syphon it usually did .

Why do you need to run it to the transom for a drain (if the deepest part of your bilge is not there)? The long run will reduce the capacity of the pump. Why not put a thru-hull just above the waterline in the side of the hull, or even in the bottom of the hull, with a 'swan neck' in the hose taking it well above the heeled waterline on its way there? (Note that the heeled waterline is lower the nearer the centreline of the boat you get than it is at the sides. Though the layout of a small boat usually makes it difficult to achieve a unobtrusive high swan neck on the centreline, the further you can get it from the outer side edges, the more effective it is, or the less height needed for the same effectiveness.)

Thanks. Good point about the sink, I'll forget that idea.

I just thought the transom would be easier to drill through, and the hose outlet would not be seen from inside. But if a longer hose diminishes flow rate, then perhaps through the side of the hull is preferable.

 

[Dellquay13]

The bigger Foxhound is similar, and I have pondered this problem. My current temporary solution (4 years and counting) is to have the pipe from the Seaflo auto bilge pump under the heads compartment sole stuffed down the galley sink plug hole when I am not onboard.

I have considered the pipe to the stern, and generally presumed it too long at about 4.5m but really it is mostly down to the vertical lift (about 80cm to the top of any swan neck needed), not the length, especially if the high point is a bit nearer to the pump with a gravity fall from there.

I might try an experiment with a hose just laid out from the pump out of the companionway and over the transom then pour a couple buckets of water into the bilge. If it largely copes then I can run the pipe in discretely to a skin fitting in the transom, near the outlet from my manual pump.

I have always rejected the idea of putting a skin fitting into the side because of getting the swan neck high enough in case I heeled down to the toe rail (not that hard with such low freeboard). I usually fit the galley sink plug when sailing in case of sudden excessive heel when seawater has sometimes backed up when the plug was forgotten, although it doesn’t syphon like a sealed hose down to the bilge might.

 

[Captain Crisp]

My seaflo seems to cope very well with approximately 6ft of length and around 3ft of climb to the transom...

 

[Fantasie 19]

Thanks. Good point about the sink, I'll forget that idea.

I just thought the transom would be easier to drill through, and the hose outlet would not be seen from inside. But if a longer hose diminishes flow rate, then perhaps through the side of the hull is preferable.

Just a thought - could you drain into the cockpit and let the cockpit drains take care of it??

 

[William_H]

Just a thought - could you drain into the cockpit and let the cockpit drains take care of it??

I think those racing rules where bilge pump is required specifically deny the use of cockpit to pump in to. I am not sure the logic however.
For my opinion assuming an outboard motor and no under water drains then a bilge pump would not be worth having. Water inside is only likely from rain and hopefully not much. Fit a hand pump if you have to meet racing requirements. As for actual sailing safety you are unlikely to get water in to cabin if you do a bucket will do. If you get holed (unlikely) then a bilge pump may not help much anyway.
However I have seen one neglected GRP boat where cockpit drains blocked up with seagull mess and cockpit filled with rain water till it overflowed the bridge deck in to the cabin. Did not actually sink but was on the way to that end. If however OP is not going to neglect his boat in the water for long period then no worries. ol'will

 

[thinwater]

I would not T it into the sink drain. You could risk bilge water coming up into the sink, and a friend once had panic-inducing water ingress which took a long time to discover was the result of the sink drain being blocked and hence not performing as the anti-syphon it usually did .

Why do you need to run it to the transom for a drain (if the deepest part of your bilge is not there)? The long run will reduce the capacity of the pump. Why not put a thru-hull just above the waterline in the side of the hull, or even in the bottom of the hull, with a 'swan neck' in the hose taking it well above the heeled waterline on its way there? (Note that the heeled waterline is lower the nearer the centreline of the boat you get than it is at the sides. Though the layout of a small boat usually makes it difficult to achieve a unobtrusive high swan neck on the centreline, the further you can get it from the outer side edges, the more effective it is, or the less height needed for the same effectiveness.)

Not a problem going through the sink if you arrange the Tee so that the bilge pump is flowing straight through, not in from the side. A common error. Shoots straight through.

No need to add a through hull. I did just as Roger suggested on my F-24. I would NOT add another potential leak spot for such a simple thing.

---

As for the effect of hose on the pump output, look up the pump performance curve (gpm vs. discharge head) and figure it out. Remember that TDH (total discharge head) = pressure head (zero if above the water line) +static head (lift) + friction head (hose plus fittings--you can look this up).

 

[Refueler]

My auto pump is T'd into the sink hose ..... BUT before the hose connects to the T piece - it loops up under the worktop to make sure its higher than the T piece and waterline.
When operating - the sink does start to fill with bilge pumps output - but only until equilibrium reached with that exiting the through hull ... one day I may fit a handi-valve on the sink to stop that.

My sink hose has a valve in it just inside the hull side to close when sailing as when heeled to stbd - the sink can backfill from being at or below waterlevel. This also prevents any water into bilge.

I tried a non-return valve - but because of the rise of hose from pump - the valve failed to open when pump operated.

 

[thinwater]

... I tried a non-return valve - but because of the rise of hose from pump - the valve failed to open when pump operated.

It's common for sailors to underestimate the effect of discharge height, friction losses in hose and through fittings, and non-return valves on output volume. For example, many check valves take ~ 1 foot of head to open. Also remember that "head" equals lift distance + friction in the hose and fittings + velocity in the hose (roughly how far the water would squirt if the hose were pointed straight up). Most bilge pumps are operating 2/3 of the way to the left of their max flow on this sort of chart, and adding something like a check valve can be the last straw. A high loop, on the other hand, costs head when the pump first cycles on, but as soon as the water fills the hose, the siphon effect recovers the head to the top of the loops, so there is no penalty for that (height is measured from the through hull to the switch water level in the bilge.

The Rule 500, for example, NEVER actually delivers 500 gph. The velocity head alone would lower it to 400 gph. The 500 gph is a theoretical number with no physical meaning ... unless the pump is pumping slightly down hill. Something the advertising department latched onto.

Don't believe me. Google pump performance curves + engineering. I'm a chemical engineer and pump performance re. design is meat and potatoes for us.

 

[Chiara’s slave]

We’ve tried a lot of bilge pumps on our XODs various. The electronic ones have proved the least reliable. Many’s the downwind leg I have spent grovelling about taking the pump apart. Float operated ones are simpler, cheaper and can be forced to start.

 

[Refueler]

We’ve tried a lot of bilge pumps on our XODs various. The electronic ones have proved the least reliable. Many’s the downwind leg I have spent grovelling about taking the pump apart. Float operated ones are simpler, cheaper and can be forced to start.

I have also given up on electronic ones ....

 

[RogerFoxTerrier]

For what it's worth - I don't race (have enough stress in the week thanks!)

 

[William_H]

For what it's worth - I don't race (have enough stress in the week thanks!)

I have seen a lot of negativity toward yacht racing on this forum. I just want to say that yacht racing with my local club has given me much pleasure over 41 seasons. It gives me an incentive to go sailing each Sunday afternoon with a specific course to follow with an escort boat on site if things go wrong. It has given me and my family friendship and community in the club. No there is very little stress beyond simply trying to make the boat go as well as possible with occasional fun with close in tactics. All good natured. I love my club. ol'will

 

[RogerFoxTerrier]

I have seen a lot of negativity toward yacht racing on this forum. I just want to say that yacht racing with my local club has given me much pleasure over 41 seasons. It gives me an incentive to go sailing each Sunday afternoon with a specific course to follow with an escort boat on site if things go wrong. It has given me and my family friendship and community in the club. No there is very little stress beyond simply trying to make the boat go as well as possible with occasional fun with close in tactics. All good natured. I love my club. ol'will

I'm not negative towards racing in the slightest. I also appreciate it's the best way to improve one's skills and I encourage my son to do it (I can't judge an efficient tack to save my life!)

It's just something that doesn't interest me. I ski, but have no desire to race; I cycle and have no desire to compete...

Although I do object to 'some' people shouting at me to get out of their way 'cos they're racing when I'm the stand-on vessel or navigating a defined channel.

 

[ChromeDome]

I fitted an automatic bilge pump, sensing by starting frequently.

Spoiled some 5 night's sleep until removed. Useless, if you want to sleep onboard.

 

[Refueler]

I have seen a lot of negativity toward yacht racing on this forum. I just want to say that yacht racing with my local club has given me much pleasure over 41 seasons. It gives me an incentive to go sailing each Sunday afternoon with a specific course to follow with an escort boat on site if things go wrong. It has given me and my family friendship and community in the club. No there is very little stress beyond simply trying to make the boat go as well as possible with occasional fun with close in tactics. All good natured. I love my club. ol'will

Some of my best times have been Club Racing .. or better termed "Round the buoys" .... nothing too serious - but a chance as Will says to try and do best with what you have .... and ENJOY !

 

[Chiara’s slave]

I fitted an automatic bilge pump, sensing by starting frequently.

Spoiled some 5 night's sleep until removed. Useless, if you want to sleep onboard.

Hence my heavy preference for float operated pumps. If they start up at night, it’ll be to save you from a soggy bed.

 

[Refueler]

I fitted an automatic bilge pump, sensing by starting frequently.

Spoiled some 5 night's sleep until removed. Useless, if you want to sleep onboard.

Depends the pump and how you mount it ...

Mounted badly - it can use the hull as a sound board ..
Sensors - yes they can detect and start pumps usually lower than the float switch type .. but then all you do is mount slight bit higher ...

They will all emit a very low volume buzz .. inherent with e-motors ... but I can live with that ..

 

[thinwater]

Depends the pump and how you mount it ...

Mounted badly - it can use the hull as a sound board ..
Sensors - yes they can detect and start pumps usually lower than the float switch type .. but then all you do is mount slight bit higher ...

They will all emit a very low volume buzz .. inherent with e-motors ... but I can live with that ..

Some of the early, simple ones would run for a few seconds, check the amps, and shut down if they were low. Newer ones will do that as default if the sensor fouls.

I have one pump that is manual (float) plus it comes on once per day for 30 seconds. This helps it clear out a very shallow bilge, and is not enough to damamge the seal, since there is nearly always some moisture around. It is not at all loud, but it still catches me by surprise a few times each year. Obviously, it is set to run when I'm awake!