Poor bailer performance on GRP BR20

[MarkDarley]

I am experiencing a huge difference in the efficiency of the bilge tank bailers between my two BR 20s (wood in the UK and now GRP in California).

The wood BR20 has two very large bailers below the main hatch for the tank; one facing forward and one facing aft. The forward one fills the tank very fast, and the aft facing one drains the tank very efficiently especially when off the wind.

In contrast the 2012 GRP boat has a tiny bung hole below the main hatch which fills the tank slowly, and the drain bailers which are medium size and either side of the forward end of the centerboard case, do a lousy job of emptying water, even at speed downwind.

I now have two bung holes in the back of the tank and two super mini bailers in the well in front of the engine well. These bung holes only partially drain about 50% of the ballast down wind (when I don't need it), and a bit more when on the wind (when I do need it!). So they help but are not a complete solution either.

Has anyone else successfully improved the efficiency of the in tank bailers in the heavier (500kg) GRP boat?  I wonder if part of the difference is the fact that the wood boat is only 320kg and therefore floats higher and faster, or is it the difference in the hull shape and flow beneath it?

Has anyone achieved proper drainage of a GRP ballast tank underway without a bilge pump?  If so, how?

Thanks
Mark

[Graham W]

Mark,

My configuration of bungs and bailers on my GRP boat works well on filling and quite well on emptying as long as I'm going fast enough.

I agree that the forward bailers are completely useless and in a difficult position to access.  I had mine removed and blanked off.  I also had a bailer placed alongside the tank bung and reversed (facing forward) to at least double the tank's filling rate, as you have in your wooden BR.

In the sump at the back I have three quite large bungs on the aft face of the tank - one each side as far outboard as possible and one in the middle.  These drain the tank, where the water is removed (as long as I'm going fast enough) by two externally mounted Andersen bailers.  Over five knots, the bailers make a satisfying slurping noise as they empty the sump. For historical reasons, one of the bailers is an effective New Large and the other a slightly less effective Mini.  In an ideal world, they would both be New Larges.  I also have a non-return air vent in the tank roof to ensure that plenty of air is available to replace the tank's water as it is removed.

The external mounting of the bailers is important - for reasons that I don't understand, internally mounted versions like the Super Mini, which is what you say you have in your GRP boat, are barely effective.   Apparently it may be possible to improve them by mounting them externally but I'm not quite sure how.

Despite all of this and unless I'm racing, I mostly empty the tank back at the dock with a strong 12V electric pump inserted through the big tank hatch aft of the centreboard, attached to a wide diameter hose over the outboard transom.  Or I use gravity when winching back on the trailer.

[MarkDarley]

Yup, I now carry a small 12v rechargeable battery to empty the tank at the dock. It is not so easy to operate single handed when underway as it involves dropping

I may fit two large bailers as fitted in Pippin and described earlier.

Boats evolve!

[MarkDarley]

Has anyone tried removing the black plastic grill on their bailers to increase flow?
Would it work?
I don't see any real reason for it inside the ballast tank as there are no lines in the tank to get trapped in them.....
Mark

[Graham W]

The black plastic grill is a Super Mini thing.  The externally mounted New Large and Mini ballers don't have them and I'm not at all sure what purpose they serve.

CORRECTION: the New Large seems to be sold with a plastic grill too, or at least it is these days.  I'm less sure about the Mini. As Mark says, the grill's purpose is to stop the snaring of control lines.  I'm reasonably sure that when I bought my New Large about ten years ago, it didn't have one.  Despite my bailers being in the sump and being theoreticaily vulnerable to control line tangles, it's never happened to me.

[Sea Simon]

My boat has the three drain plugs on the aft end of the ballast tank, in the sump, from new. I used to "crack off" or slacken the black/red tank cover, so as to let air in. This helped tank drainage, however I noticed that at some time someone must have landed heavily on the loose hatch, and in so doing cracked the male thread on the tank rim. Luckily spares are readily available, if a little time consuming to fit (lots of small fiddly bolts); renewed.

To help the tank drain more easily, I too fitted a one-way air vent (using a "jiggle siphon" fitting) at the front of the tank top. Access to the underside of the connection nipple via the inspection port. I think this was originally a Claus/Llafurio mod? Cheap, but fiddly.

The two original externally mounted "Mini" Anderson bailers (no grilles) are, shall we say, "temperamental". Occasionally good, often less so. I haven't figured out why.
Maybe Speed/draught/fouling/heel...and resulting hydrodynamics? Much less effective than those I've used in dinghies.

[Llafurio]

To help the tank drain more easily, I too fitted a one-way air vent at the front of the tank top. Access to the underside of the connection nipple via the inspection port. I think this was originally a Claus/Llafurio mod?

That is correct. Amongst a good few other mods and features of the Raiders.
C.

[Andy Stobbart]

FWIW I too have just experienced poor ballast loading and draining for myself this weekend.

I have recently acquired a new to me wood epoxy Denman Marine BR20 from Tasmania. Beautifully constructed. One small sea cock/through hull in the bottom of the ballast tank accessible via the inspection hatch; another one between the aft end of the tank and the outboard well rather inaccessible with the bung being below the outboard inside the well; and two drain bung holes in the two Venturi sumps either side of the well with a small self bailer in each.

I went out in strong winds and immediately got flattened under just jib and mizzen so thought I'd better try the water ballast for the first time. Filling was very slow through just the bottom hole. When it came time to try to drain the tank I sailed backwards and forwards for hours and only really managed to get it half empty.

I am definitely going to try a manual or electric bilge pump to be dropped into the tank via the access hatch as & when  needed, with a discharge tube into the outboard well.

[Graham W]

Andy,

If you already have a 12V battery on board for GPS etc, I strongly recommend the 1100 gph electric pump made by Rule.  It's small and robust and in the UK only costs about £40.  When dropped through the ballast tank hatch,  it takes less than five minutes to drain the tank over the outboard transom and into the outboard well.  This is an upgrade from the 500 gph version that I had previously that costs around £20.

If, like many of us, you have a manual Whale pump fixed to the forward side of the outboard transom, this can also be pressed into service if you have a suitable set up.  For example, Matthew P has this https://www.swallowyachtsassociation.org/smf/index.php/topic,935.msg5960.html#msg5960.

[Llafurio]

To begin with, this thread is about poor bailer performance on GRP Brs.
The plywood BRs are significantly different re their cockpit design and draining system.

Though I have no in-depth expertise with the plywood BRs myself, I had commissioned and sailed the first plywood SeaRaider, after which the plywood BRs were fashioned, and had been involved in improving the ballast system on that, and on the following plastic BRs.

Ideally, you can find other plywood owners here on this forum who can advise in more detail. There would be Mark Darley, and Jeff Curtis whoch you may contact.

...
I am definitely going to try a manual or electric bilge pump to be dropped into the tank via the access hatch as & when  needed, with a discharge tube into the outboard well.

You may want to check first if your current setup is "state of the art". On the early SeaRaider and BRs the original tank filling and draining setup was real crap. Important improvements have been achieved since for the plastic BRs. I do not know what of that has filtered down to Downunder.

The principles for a best possible ballastwater management system (intake and outsuck) are as follows:

All bungs must have max possible opening diameter, 1 - 1 1/2"  (The early boats had 1/2". Then, there were plastic bungs used which looked big but had a small open diametre. Best were chromed brass bungs by Osculati.

Ideally, the tank is filled through force-feeding, in SR Craic that was done through a reverse.mounted Elvstrom  self-bailer.

For best and quickest draining, there must be multiple drain bungs in the rear wall of the ballast tank, one central, and one on either side.

Then, the self bailers. Two pcs. minimum, outside mounted. Best work the Andersen/ elvstrom Minis.
As you mention "Venturi" in this context, Craic originally had two true Venturi bailers "Super Suck". They had no non return flaps, and did not work well. They were replaced with Elvstoms, and that helped.

And finally, the whole system can not work well without the ballast tank being vented during intake and discharge.

Finally, most boats today have retrofitted manual bilge pumps to empty the tank via the sump, when the boat is not moving, or is not moving fast enough.

I hope this helps.

[MarkDarley]

When at speed down wind, I am now finding that the ballast tank on my grp Bayraider 20 works well with the two drain holes at the rear of the tank, and the bailers either side of the centerboard deployed. However is is not easy when single handing to go forward to open those bailers.  I am living with it!
Mark

[Llafurio]

Your GRP-BR20 appears not to be set up well with regards to ballast tank self-draining.

It has long been established that the original two fore selfbailers work particularly inefficient, by comparison, and are out of helmsman's reach anyway. They are so inefficient, because selfbailers have to counter the "head" of water pressure where they are mounted. With boats at speed, a bow wave builds up and increases the head for the fore bailers.
Because the fore bailers also usually cause leakage into the empty tank it has long been recommended to seal the fore bailers shut for good, and leave them out altogether on newer boats. I think this advice has been followed by the yard since.

The most efficient ballast tank self-draining is through the sump at the rear of the cockpit. IF that is set up as follows: THREE drain bungs in the rear wall of the tank, a big one in the centre, and two on either side, as far out and as deep down as ever possible, and with the biggest possible openings for optimum flow rate. The Osculati brass bungs have the best size to opening ratio there. However, the yard still fits plastic ones which are not so good.

For selfbailers in the sump, again, two outside mounted Elvstrom Minis (NOT Super Minis!) are good, but three are better. Again, one central, and two on either side, as far out as possible.

All a bit tricky to retrofit, but worth the effort.

C.

P.S.
Also the original water intake bung inside the tank should be widened, if you still have the old narrow plastic bung. C.