Thoughts on bilge pump though-hulls

[ChuckieTodd]

As I contemplate the appropriate location for a bilge pump through-hull, I've come to realize something about the 26M's design. If one considers the design of the rudder tubes and their location in relation to the waterline, it's apparent that they are basically one inch diameter pipes open from the sea into the hull. From this realization, I conclude that placing a through-hull any higher on the transom than the top of these tubes would be largely pointless. Does anyone else see it this way?

[Matt19020]

I placed my thru hole for the bilge pump about 2" above waterline on port side behind sink....
DO NOT DO THIS!...
Everytime it heeled it "pushed" water into bilge...
Put a valve on it and it is there for emergency only or long spans of time at dock when away from boat.... Never had to use it.... bilge remains relatively dry...
I am too lazy to reroute hose to a higher stern level...
I put a water alarm in the bilge under the battery area if there is a problem it will sound I will inspect and address problem as it is happening

[seahouse]

I was wondering what the heel angle has to be for these to leak. Maybe never? When I'm in the water I plan on checking this out. Could it be that this is what limits the heel angle that the factory recommends?

The leaking, although with much less volume, would actually start happening several inches below the top of the rudder tubes where the tubes penetrate the hull. I haven't dissassemled this to confirm it, but it looks like there has been no attempt by the factory at sealing this joint. I'm thinking a large sponge wrapped around each one might help by absorbing some water before it makes its way into the bilge. I prefer my bilges to be bone dry, semper. Might not be realistic with this boat.

Just finished making a seal/wiper/bushing/guide for the steering shaft where it penetrates above the well. Will post that, (maybe when the snow flies).Then I noticed the area you're asking about.

I'm presently trying to seal the leaks such as this throughout the boat. Beaching with your bow high and transom deeper in the water could be problematic in these areas, as someone on this forum has recently experienced.

So to answer your question, (or try) I would expect that it would depend on whether you were positioning outboard or inboard of this from the centreline of the hull. If you are outboard of the point in question, (be it the tube end, or the unsealed joint) you would need to locate your hole higher up on the hull, to allow for heel. If you were more toward the centreline, then you could be at the same level. I'd go a bit higher, of course.

- Brian.

[u12fly]

Well first off, your thinking is correct... Basically once the boat fills with water and sinks to the point where the rudder torque tubes (on the inside of the boat) are below the water line, water will start entering the boat via the torque tubes (as they are hollow) and around the fiberglass towers supporting the tubes. At this point you will need a rather large, if not multiple bilge pumps to expel the water leaking into the boat.
I have several modifications in this area. I plan to post these in the next month or so after I get caught up and get my boat back in the water. I have made modifications to the inside fiberglass tops of the torque tube supports, mainly because the rudders from the factory have way to much slop in them. Mine now go through tight machine fit delrin bushings that are bonded to the top of the fiberglass towers.
As for the bilge pump, I’ve rerouted my sink drain which left the factory 3/4" through hull only draining the transom. I left the “T” installed (which was originally from the sink) and hooked my 500 GPH bilge pump there. The trick is the hose from the bilge pump is actually routed about 1 foot above my rudder torque tubes, bonded to the aft interior wall. This effectively means the boat would have to be sunk well beyond the rudders before water will back feed through my bilge pump and I do not need a check valve, nor do I need to keep the bilge drain above the water line.
I did add an additional 1” through hull drain, it is dedicated to my sink. I installed that immediately to the left of the original factory through hull (i.e. outboard) on the same level. I felt I needed a larger drain to support my sink which now has running hot and cold water sourced by an electric pump. Since the inside of the hull starts to curve there (as material is built up for the rudder towers) I had to grind the area flat to get the nut of the through hull to be perfectly flat. Don’t worry the fiber glass is over an inch thick there!

[seahouse]

Hey U12!

Sounds perfect! The Delrin will reduce friction and will address the slop to the degree that the tube is round. How much out of round did you find they were? The clamp and bolt near it exacerbates the problem. Did you do anything specifically to address the leakage at this location? Your close tolerance will certainly minimize it.

Delrin is best for the application, but I had no pieces sitting around large enough so I used UHMW (next best) for the bearing surface, and recessed a urethane seal inside that for the sealing/wiping function. That's for the 1" steering shaft near the tansom well which is a thrust, not a rotational bearing, but I plan on using that same construction on the rudder tubes, if this works.

I'm curious to know if leakage in this area is something I dreamt up, or does it happen? My Mac has yet to see water (even outside the hull) so I can see first hand, but I haven't heard many complaints about it on this forum (except for the excessive lash), so maybe it is non-existent or doesn't get noticed.(?)

Looking forward to your posts.

-Brian.

[FinallySailing]

One way to reduce water flowing back whilst heeling is to have a riser loop This will extend the discharge tube well up above the waterline to reduce the chance of water ingress. Some people do not advocate the use of check valves, they can clog up and will malfunction. I found this article really helpful when I did the refit on our Mac26S earlier this year:

http://www.yachtsurvey.com/bilge_pumps.htm

After I managed to get her flooded on land I've now got a rule mate 2000 in the bilge, the old rule mate 500 is in the aft lockeer and I've got a long enough hose with a strainer on the manual pump that can easily reach any point inside from its position in the aft locker.

[Catigale]

Riser loops good. Check valves bad.

Best is a shutoff at hull of course.

[Divecoz]

Humm ? Maybe.....But as I see it and live it, our boats are small and every inch is used .. an air lock for me was , Unsightly and an irritant / in the way..
I have been using check valves for 5 years now and have had zero problems so far I and many here it seems, are able to find faults ( doomsday
scenario ) with anything or any system anyone designs or develops..Should we have a shut off valve? Sure. Why not? As long as you have it located , so you can quickly and easily get to it .. hummm theres two huge issues.. I have 3 pumps.. center aft under rear berth 500 gph..PRIMARY one each S.B. an Port at or about the companionway 2000 gph BACK UP's...I have 3 large batteries as well and I am going to replace those with 3 new and bigger batteries.. basically the same locations..What if all 3 went bad ?? Hahahaha I GUESS.... I should now add independent sensors too, and the list goes on and on and on.. I do need to re- plumb mine as I am no-longer happy with what I have for discharge locations.. I do have a Full Throat 1" bronze shut off and thru hull for my sink and 1 bilge pump. A lot of good that one does me..... if I cannot get to it or forget I need to open it.. Its always closed when sailing..

Riser loops good. Check valves bad.

Best is a shutoff at hull of course.

[Crikey]

This post covers three good areas for me!

First: bilge pumps are very good to have in place in the boat ..... even three of them like Divecoz has. It's not just taking water from an unlikely location like the rudder support structures in the stern, but striking a dead-head, another boat or somesuch where the influx of water starts getting serious. Three pumps beats one for volume and redundancy in this case.
To properly cover something like this a larger diameter line sidesteps plumbing into the sink drain and I think the stern location, along with a checkvalve and riser loop should cover most bases. The existing opening could be enlarged to accomodate both together. I've had a plastic checkvalve in my basement sump pump for years without any hassles.

Second: I've been tearing my hair out for several months over a major rudder/steering mod and agree with the need to eliminate both the shaft slop as well as the source of potential leakage, though I will say angled beaching due to the tide going out is not much of an issue on lake Ontario. Good eyeopener though! The boat should be stern to the shoreline particularly if the tide leaves you at an angle, and the ballast should be gone in case bad weather with the incoming water pitches the stern below the leak threshold.
The rudder pintle (post) is actually 1.25" in diameter and when I examined mine after only one years season of use found it had ovaled noticibly in the top hole (there are three each in the transom mounting) where the post exerts the most pressure on the fibreglass, due to the sideways steering force applied by the pitman(?).
I will eagerly await any of your rudder mod posts dealing with a slop and leakage reducing bushing in this area! Here's a link to a supplier of PTFE bushings that I'm considering (not sure if this is like Delron).

http://www.polygoncomposites.com/divisi ... KgodoyewUA

The beauty of this material seems to be it's availability in 1.25" ID and 1/16" wall thickness with a flange at the top, as well as customer specified lengths. It will also bond well to resin.
I haven't jumped on this fix just yet but pending further input concerning this irritating area, from other experimenters/and their discoveries, will most likely end my mad mods with this product, if I ever finish them! I've got a couple of weeks coming soon to check out my delusions, and will post a separate entry - if I make it back.
Essentially:
Baystar hydraulic steering
Rudders dropped two inches & reinforced against flexing
Pitmans raised two inches
Heim joints in linkages
Skegs linked to rudders for power handling
Bungee hold down tension
Pully uphaul
Whew!

Lastly, coming back to the onboard water thing - it would be nice to have some sort of visible a/o audible indicators located on the pedestal, connected to one or more level sensors. What works here, and is capable of dealing with corrosion and neglect?

Ross

[Russ]

I've never really signed onto the idea of any bilge pump keeping up with a hull puncture. If you hit something hard enough to hole your boat, you better be calling for help and get ready to get wet. Although I've heard of a case of an X with a leak from the centerboard post where a pump came in handy after the leak was plugged. The M has no real place for water to enter except rain.
I guess a single pump is not a bad idea in case you get some water come in as it's easier than bailing. But for a life saving device, I wouldn't count on it.

[Catigale]

You need a serious bilge pump to deal with a hole in the hull. the electric ones are good for rain only.

[Divecoz]

I agree to some extent Cat..Except ...
How big a hole will you make? How big of a pump / pumps do you have? Is it better to just fill the down stairs uncontrolled than fight the flow..??
Can I ? Might I ? Be able to get back with my 4500GPH / Best case 75 gallons a minute pumping like mad and me heading in as best I can or even heading for shore?? If its a major hole? Yes your screwed and you better have left ALL the Styro in place 2nd call is your insurance man.. 1st is Sea Tow..
I've been in Real Bad Weather Twice. Worst one I was ( auditioning for the part of Lt. Dan ) and was under sail and I was taking on quite a bit of water for well over 1 hour . My 3 pumps took pretty good care of me. Well good enough that my concern about water down below was minimum as long as I could keep her up right and as long as I didn't de-mast her.. when I finally could I started the motor. Yes both my aux bats had taken hard hits.. but I was safe dry and the dedicated bat started my Merc 50 EFI BF .." Sq Area of the hole has to be smaller than the total sq area of your pumps..with that I do agree

You need a serious bilge pump to deal with a hole in the hull. the electric ones are good for rain only.

[seahouse]

Yabutt this pump could handle a pretty big hole...

http://www.youtube.com/watch?v=7-KczCp0 ... re=related

(Sorry - I stole this link from Crikey) And I'm so ashamed.

[u12fly]

Hey U12!

... How much out of round did you find they were? The clamp and bolt near it exacerbates the problem. Did you do anything specifically to address the leakage at this location? ...

I'm curious to know if leakage in this area is something I dreamt up, or does it happen? ...

Looking forward to your posts.

-Brian.

Hi Brian, just wanted to get you some answers... I don't know how out of round they were, but I had a good quarter inch slop which made the rudders bang and be noisy if left in the water, also it added to the slop in the basic steering of the boat. I realy never had much water issue, my boat is pretty dry.

Chris.

[Crikey]

Just to cover all bases, I thought I'd cover things with one of these pump systems:

http://www.youtube.com/watch?v=hhs47KP0 ... re=related