Sump Pump

[Julian Swindell]

It is interesting to hear your use of fenders in the tank. I do the same on my Baycruiser but for a different reason.

The Baycruiser has two ballast tanks, one under the cockpit and one under the forward berth. This is to allow the cabin floor to go right down to the keel to give some internal headroom. The tanks are linked by a reinforced hose and both are filled by a reveresed self bailer in the cockpit tank. The initial problem was getting the forward tank to fill. With me in the cockpit and the rear tank filling first, the water had to flow uphill to get into the bow tank, and it didn't fill fully. Standing a 200kg gorilla on the bow would do the job, but I don't usually take one sailing with me. I now put four small fenders into the cockpit tank, which makes the back of the boat more bouyant and both tanks now fill and the boat floats level on her waterline.

The tanks are emptied using a manual bilge pump, which pumps out the forward tank first, which is not the best location, but there are reasons for the plumbing layout (The same bilge pump can be used for pumping out a flooded cabin, but happily I have never had to do that.) It takes 10-15 minutes of pumping to empty the tanks. I only ever empty them when I am hauling out. I leave them filled all the time. I have tried sailing, rowing and motoring with empty tanks and any gain in speed is too little for me to notice.

[Graham W]

   one panel of the fixed (closed cell) bouyancy that should be attached to the underside of the cockpit floor inside the ballast tank has detached itself and is now free to float around in the ballast tank.  Has anyone had a similar problem?

I think this must be a common problem.  Three of my four panels have detached.  See photo below.

Has anyone worked out how much water each panel displaces?

[Peter Cockerton]

My GRP Bayraider 22 also suufers from floating foam panels, this started in late August 2010. I raised the matter with Matt and he was kind enough to send me a letter on the matter to alleviate my concerns.

The letter makes the following statements

Swallowboats are confident that the foam in a GRP Bayraider is serving no usefull purpose.
It was originall placed under the floor of the epoxy Ply boats to fill the empty space that would be left above the flooded tank due to the boats being lighter. The tanks therefore will fill completely with no foam on the bottom..
Without the foam they will take on another 70kg of water which will help stability.
The boat has plenty of reserve buoyancy in multiple independent chambers, the foam is not needed for this.

As and when the foam breaks free i would advise pulling it out of the access hatch, breaking it up if necessary.

Peter Cockerton

[Llafurio]

... Swallowboats are confident that the foam in a GRP Bayraider is serving no usefull purpose. ... As and when the foam breaks free i would advise pulling it out of the access hatch, breaking it up if necessary.

I don't take that. IMHO the foam under the floor is needed to keep the cockpit floor dry and selfbailing when the boat is on a mooring with the tank full. Rather than taking any loose foampanels out, you should try to re-fasten them. You could generously smear Sikaflex 252 onto the top of the foam, slide the piece into position, and use an inflated aircushion like a Crewsaver underneath to press it upward onto the underside while the Sika bonds and sets. That is how I would try it. Maybe best to do it in winter storage when the tank is dry.

[Peter Cockerton]

... Swallowboats are confident that the foam in a GRP Bayraider is serving no usefull purpose. ... As and when the foam breaks free i would advise pulling it out of the access hatch, breaking it up if necessary.

I don't take that. IMHO the foam under the floor is needed to keep the cockpit floor dry and selfbailing when the boat is on a mooring with the tank full.

Hopefully Matt will pick this up and respond, i have had only one panel removed to date with another now floating which will stay that way for now. With one panel out, the tank filled and the access hatches to the tank closed the cockpit floor remains dry.

Peter

[Graham W]

An alternative would be to have a couple of Crewsaver 35 litre buoyancy bags permanently inflated in the tank to replace the blue foam.  They would have to be carefully placed (and jammed in to stop them shifting about) as there are several sharp screw ends protruding into the tank, from above and below, mostly along or near the centreline.  Anyone who has ever stuck an arm into the tank can vouch for this!

[Colin Morley]

Two threads now here.
1. yes i do have a bit of loose foam in the buoyancy tank floating around when it is full but it does not seem to cause any problem.

2. Yes my Garmin sometimes does not work when the battery is fully charged. This is due to slightly corroded terminals. One marine engineer sorted this out with Electrolube spray but last weekend I just pushed the socket and plug together several times to clean it and then it worked.

Someone said I could spray WD40 on it but I am not sure whether that would help.

[Graham W]

my Garmin sometimes does not work when the battery is fully charged. This is due to slightly corroded terminals. One marine engineer sorted this out with Electrolube spray but last weekend I just pushed the socket and plug together several times to clean it and then it worked.

Someone said I could spray WD40 on it but I am not sure whether that would help.

Dielectric silicone compound (made by Dow Corning) http://uk.farnell.com/jsp/displayProduct.jsp?sku=537019&CMP=e-2072-00001000&gross_price=true is quite good for sorting out poor connections due to damp/corrosion.

A Garmin GPSMAP replacement power cable costs about £20 on eBay and may help, depending on where the corrosion is.

[Simon Knight]

Dragging this thread back to the original topic ;-)

Originally my BR had no drain plugs but has had a small one fitted on the centre line of the tank with the intention of allowing the water to drain into the sump ready to be pumped away.  Unfortunately this does not drain fast enough and hardly a trickle comes out. 

I was going to connect my pump into the tank via a "tank fitting" but is the consensus that three drain plugs work well, allowing the water to flow into the sump at a rate matched by the pump chucking it over the side ?

Simon

[Simon Knight]

I have just located some pictures I took of Mark Edmondson's Bayraider Mini the Moocher.  He can separate the hose if he needs to pump out the sump directly.

Simon

[Llafurio]

What is the purpose of Marks installation? : To put selfbailers out of work? To suck air out of the tank once the waterlevel has dropped below the top of his drain fitting?

What I can see is that he does neither have the right drain bungs nor the right selfbailers, in the right places, and that his fine plumbing -and manual pumping- would be rendered unnecessary if he had.

[Simon Knight]

I think the idea is to be able to empty the tank while not moving through the water; lets imagine that one has just completed a hard days sail in fresh winds and are now tied up and living under a tent - and you want to empty the tank.

Reading this thread there seem to be three options: a) One or more  bungs mounted in the rear wall of the tank draining into the sump.  Water is then either pumped into the outboard well using a bulkhead mounted pump or drained out through the self bailer.  Provision has to be made to allow air into the tank to replace the water draining out. b) Mark's arrangement that pumps directly from the tank and may also allows the pick up pipe to be taken forward. c) pump water from the open hatch.

Reviewing each in turn.

a) I have tried this with a single 3/4 inch bung.  The aperture is to small as the hand pump removes water to quickly from the sump.  Also, as others have noted a certain amount of water remains in the tank when no more is draining through the hole.  Mathew P is using this system but with a 40mm diameter drain plug.  Llafurio advocates two additional drain plugs one on each side plus the centreline one.  I am not clear if these are all the same size or not.  I note that if I leave my boat draining while on her trailer with her bow high I am still left with quite a lot of water in the tank.  More than could be sponged out.

b) While I don't know the development of Mark's system I guess he has been seeking a system that works for him, I guess he fitted the second self bailer in an attempt to improve on the performance of the first.  I have a faint memory that the boat cam fitted with the centreline bailer but that it did not work at all well.  His system may be viewed as just a drain hole with a pump attachment point.  I don't know if he uses a pick up point further forward.

c) Pumping from the open hatch can be done.  I tried it using a plastimo hand pump and it was not much fun plus I know if there is an open hatch either I or something important will fall into it.

For the record my BR is No. 20, Carpe Diem, and she is fitted with two Super Max bailers inside the tank and a single Super Mini on the starboard side of the sump.  I am considering fitting a plastic 1 inch through bulkhead fitted purchased from a local farm supply shop.  This can function as either a normal drain hole or allow pump hose to be fitted on either side.  I enclose some pictures of the fitting, the white cap is my existing drain hole cap.

What tool is recommended to cut the holes in the tank?  I find it a little tight for a normal drill.

best wishes
Simon

[Colin Lawson]

Luckily Lidl's were selling rightangle attachments for electric drills when I was doing the same job on my BR20. I cannot remember the cost (no more than a tenner) but it was so cheap that I thought it worthwhile even if I never used it again.  Did the job and looks as if it will be up to any uses I have for it in the future.  I expect you can get them reasonably priced and you never know when they will be useful.

I have two central and two lateral drain plugs in the rear of the ballast tank (I would go for a larger central one in future - the water drains out quite slowly) and a whale pump as in Simon's photo.  Works well but still left with plenty of water in ballast tank so have installed a coiled length of hose to the whale pump arranged so that normally it sucks water out of the sump but when I want to drain the ballast tank completely I can pass it into the central hatch.

I have simply put a drain plug into the central hatch to let the air in or out when the hatch is closed.

I have installed one extra off centre surface mounted self bailers and will replace the original off centre internally mounted self bailer with a surface mounted one (will have to be next size up). 


Colin

[Llafurio]

...
I ... will replace the original off centre internally mounted self bailer with a surface mounted one (will have to be next size up). 

As a cheaper alternative you can recycle the present internally mounted bailer. You simply take it out and mount it under the hull, using the same holes. Looks a bit protruding then under the hull, but that is OK as it sits there in front of the protruding lamellae frame anyway. C.

[Matt Newland]

Dear All,
Thanks again for all your discussion on this subject. Apologies for not writing sooner - summer is our busiest time. I wanted to let you know what we now fit as standard to BR20s and Expeditions and what is still for further development.

We currently fit 3 small (20mm) bungs in the back face of the ballast tank, but have now hopefully found a supplier of a much larger 40mm diameter bung, imported from Australia. So we will do exactly as Claus recommends (on this occasion!) and fit a large one like this centrally, with the two smaller ones outboard on each side.
Regarding the bailers. A long time ago Claus impressed on me the performance advantages of the smaller bailers compared to the larger ones we used at the time. So we switched to the smaller sort but I unfortunately did not appreciate the considerable difference he also detected between mini's with external mounting flange, and those with internal flange.
I find it hard to believe that there is any material difference between the two, if they were both mounted identically. So if there is a big difference, it must come down, as I think Colin suggested, to the smoothness of the hull around the perimeter of the bailer - ie is it fitted perfectly flush with the outside of the hull.
I am about to do some more investigation in this area (fitting two different Bailers to my boat) but will probably end up agreeing with Claus that external flange is better, if only because it is easier to consistently fit.
Lastly, the foam under the BR20 floor. When we designed the GRP boats we did not know for certain, until the first one was finished, how much she would weigh. If she ended up lighter than planned, then the ballast tanks would not fill entirely under the weight of the boat. This would have been a disaster, as there would have been air in the tank and so the water would be able to slosh from side to side. To avoid this possibility we decided to install 40mm of foam under the floor, to fill 40mm worth of water head and give us much more margin in the event the boat was too light.
In the end all was fine, but we decided to leave the foam in place because as the boat is 100kg heaver than the wood epoxy version, she does not need quite as much waterballast. The volume of foam equates to 70kg of water so with or without the foam, there is very little difference.
So if yours is coming loose, you can either cut it up and pull it out the hatch, or just leave it as extra closed cell buoyancy.
The water level outside, with the ballast tank full is pretty much on the cockpit floor level.
This means that if you leave the boat with tank full on a mooring and it rains, you will likely end up with some water at floor level, a few mm at least. (The boat will not sink at her mooring as she has plenty of reserve buoyancy - what we are talking about here is the equilibrium water level when the bailers in the sump are left open to allow rain water to wash through -and seawater to back flood).
If you remove the foam and fill the tanks, the boat will take on an additional 70kg of weight, and due to her waterplane area of about 6.7 sqm will therefore sink approx 10mm more on the mooring, so taking in 10mm more rain/seawater on the floor.
So Claus is right in that if you remove the foam, you will end up with more water to bail or pump - 10mm spread over the whole floor is approx 20 litres, but I doubt anyone will notice the difference, and it could be resolved with 2x 35kg buoyancy bags if it became an issue. Alternatively pump/bail her out when leaving her on a mooring which has the added advantage of minimising any fouling issues and reducing the weight and therefore stress on the boat if the mooring is a drying one.
I hope this clears things up somewhat.
Matt