Filler for deep bilges

[bigd14]

There has been an active discussion about filling in the deep keel sumps behind some models of Ericsons at the Ericson forum (this seems to be a fairly weak spot on the hull that can be damaged if one backs into submerged objects). Someone mentioned using sand mixed with epoxy. Apparently the sand absorbs the heat from the epoxy kicking off and forms a waterproof mix better than concrete or foam. Has anyone tried this, or used this technique? If so, how much epoxy did it take to wet out the sand?

Thanks,

Doug

[Rachel]

Maybe I shouldn't be replying, as don't have any experience with sand/epoxy. But I do sort of wonder about the filling-in-the-deep/weak-sump concept.

My mind starts to turn and I wonder... if it's weak and filled in with solid epoxy, would it make a nasty stress-riser just at the top of the fill line? What about strengthening it by adding fiberglass in a layer form (i.e. build up the structure). Then you would also have the benefit of a deep sump still. Of course I haven't even seen it, so I could be way off. Do you have a diagram or photo of the model in question? It would be interesting to see it.

So in what you are describing, are they "thickening" the epoxy with sand instead of another filler?

The closest thing to that I have seen was people running cool hose water over the outside of a rudder that was being rebuilt with "lightweight" thickened epoxy in the center core. Just enough to cool it down a bit as it kicked (checking temps with infrared thermometer). But that was thickened with something more traditional; microballoons, if I remember correctly

Rachel

[Tim]

Sometimes leaving well enough alone is the best approach. This sounds like a solution in search of a problem, as least with the given information.

[mitiempo]

If it is truly weak I would add epoxy and cloth layers to strengthen it, but Ericson built a solid boat so I have my doubts. I would keep it as a sump - good place to cool wine or beer.

[Paulus]

Would it be advisable to raise a portion of a deep bilge, as I have on Guillemot, in order to create a small well for the water to collect and get pumped out, rather than having the entire bilge (about 8 ft or so from stern to center of the boat) with 1 inch or so of water at all times...

It would certainly create a smaller area to treat and clean to prevent Smelly Bilge Syndrome.

[bigd14]

It indeed may be a solution in search of a problem for most situations, but it seems to have come up several times with Ericsons and has been the subject of several discussions. I don't think the area is inherently weak, per se, but it is hollow, and there are a couple instances where the very narrow aft section of the keel has impacted something and been damaged because there is no supporting ballast material behind it.

I have mixed feelings about it. On the one hand the river I am in doesn't have many rocks where I do most of my sailing. But, the river is pretty shallow in spots and there are plenty of logs and deadheads and the worrier in me says why not fix it. However... since I just learned that it would take several gallons of epoxy to use this technique, i probably will not worry about it. If anything I may put some two part foam in the bottom half. We'll see.

[Hirilondë]

............ (this seems to be a fairly weak spot on the hull that can be damaged if one backs into submerged objects).

First of all I would try to avoid backing into submerged objects. Actually, I don't see how one could back into them fast enough to damage a boat.

Second is the seems to be a weak spot comment. Who has determined that it is a weak spot? What criteria is this comment based on? The after approximately half of a Renegade keel is open all the way to the bottom and I certainly would not consider it weak.

I guess I just don't understand how this kind of concern can come up so many years after the boats were built. And I seriously question the validity of the comments made to this effect.

[Duncan]

...Second is the seems to be a weak spot comment. Who has determined that it is a weak spot? What criteria is this comment based on? The after approximately half of a Renegade keel is open all the way to the bottom and I certainly would not consider it weak.

I guess I just don't understand how this kind of concern can come up so many years after the boats were built. And I seriously question the validity of the comments made to this effect.

I have similar doubts, and I wonder if this is some sort of "urban legend" or something.

The reason I say this is that the surveyor I hired claimed that this "was a weak spot on Cape Dorys, because it can get 'punky'". The recommended fix was to grind and reglass the aft lower portion of the keel, and around the rudder gudgeon.

The previous owner dutifully cooperated and did the grinding, but found no evidence of anything wrong. He and I got the surveyor to inspect it and sign off that there was no problem after all.

I also heard a guy at a boatyard talk about hull delamination from water in the bilge on a similar hull. I don't think he knew what he was talking about either, and was just speculating.

It's funny how things, once repeated, can get exaggerated or speculated upon, and then become "common knowledge". I think this is perhaps one of these "legends", since I've never heard a credible report of weakness or failure in this area.

[Quetzalsailor]

I'd resist filling something like that with something I could never remove. And I would not go looking for trouble; watch for cracking or seepage.

LeComte NE38 Mk I and Mk II's were/are a little iffy in that place since the hulls were moulded in halves and glassed together along the centerline. Pretty hard to tab across the join down in the trailing edge of the deep keel. Mk III's like mine have a spade rudder and a separate moulded piece to finish the trailing edge of the keel.

Morgan 27's have no bilge. They're basically big dinghies and the little bit of deadrise they have was filled with a marble dust and polyester filler, rather like a cultured marble countertop. There was no removing that stuff, either. Dad's boat had collided with something big and heavy, a piece of dock, maybe; there was the impression of a bolt head punched into the leading edge of the keel(!). Anyway, the keel flexed the bottom enough to crack the filler and there was no repairing whatever might have been wrong beneath the filler.

[barrybrown]

This has long been a concern with fiberglass boats with internal ballast and deep sumps, not because of backing into something but for grounding on rocks or coral which can grind through those sections quickly letting in water. After hurricane Bob I went around to some of the local harbors to look at damage and saw numerous boats with with these sections damaged, one SC 31 had worn away and lost some of its lead pig ballast.
My last Triton had a deep sump, my current Triton (just a few numbers newer) has the the bilge partially filled, up about 9 or 10 inches, this appears to have been done by Pearson. While this may provide a little protection it takes away a large part of the cavity restricting the size of any additional water tank. I would hesitate to fill with anything heavy in a small boat without first considering the tradeoffs.

Barry

[bigd14]

Lots of interesting perspectives. I think, for my purposes, that I will leave well enough alone. That said, if my local sailing grounds were rocky and shallow enough to risk bumping the bottom once in a while I would be inclined to do something. I have tapped around down there and it does not feel very substantial. And I don't have enough clearance to use it for tankage. Thanks for a great discussion!

[Hirilondë]

I have tapped around down there and it does not feel very substantial.

It does not "feel" substantial? What does it feel like that would lead you to believe this? Does it flex when you tap? Or do you really mean that the hollow sound makes you believe it is not substantial? The hollow part of the Renegade keel sounds hollow yet is is a full 1/2" or more thick. Compared to modern construction practices this is absolutely massive. Considering that Ericson like Bristol were both 1960s spin offs from Pearson and the 27s were all built in the 70s, I can't imagine that construction is much if any less hefty. Do you know first hand just how thick the shell is in the false keel? What besides a forum discussion and that it does not feel substantial do you have to base your fears about construction on? Have you considered installing a drain plug and in the process seeing for yourself just how thick the fiberglass is?

I have to scratch my head and wonder when I see threads like this. Not at the fact that people would ask for advice or thoughts on this type of subject, but at some of the totally unfounded information that is out there disguised as fact. That this misinformation would also lead people to take action that not only does not resolve the supposed issue but also compounds things by adding other problems like the epoxy encapsulated sand would most likely do is even more scary. I won't even get into what I think of that idea here as it is a subject all of it's own.

I can't say how this whole Ericson false keel problem idea got started. But I will say that I have never seen any evidence presented in a competent substantiated manner that would lead me to believe it is even exists. I also think it is a shame that some Ericson owners are having fears about their boats that there is no real evidence to warrant. If someone has such evidence or documentation please show it.

[bigd14]

Here is the link that got me thinking about this issue (there are some other more recent discussions about this issue too, but this one is most relevant).

http://www.ericsonyachts.org/infoexchan ... t=e27+keel

And when I say that the keel sump area doesn't "feel" substantial I mean that it feels a bit flexible, like some other parts of the hull like the topsides. I can get the hull to slightly flex if I push on it. Its not more than 1/4 inch deep topsides, and the keel area "feels" like it is a similar thickness. If it were 1/2 inch thick, i would imagine that it would "feel" much more solid and I would not be able to flex it (the internal sump area is only about a foot long fore and aft). I believe the trailing edge has solid material in the last few inches. But the sides of the sump where the hollow portion are what feel "less" substantial than what i would have expected. Admittedly, without cutting into it, I am only speculating on the actual thickness.

Anyways, it wasn't my intent to create an uproar with this issue, but it seemed from the link above to be a legitimate concern for some folks. And after spending over 2.5 years and a goodly portion of my salary restoring this boat, I want to make sure that I am considering as many potential issues as I possibly can. Obviously above all I should consider avoiding potentially damaging circumstances. And you better believe I will with all this time and $$ invested!

Doug

[Rachel]

Well if it's flexy, I could see where you would be concerned. If it were me, and it were flexy and bothering me, I think I would built it up with fiberglass - maybe add a few layers. Keeping in mind stress risers and such.

[earlylight]

Doug,
I agree with Hirilondë. If I were in your shoes I believe I would install a bronze garboard drain and get a first hand answer as to the thickness of he substrate by measuring it once you had drilled for the drain fitting. At that point you would have much more definitive information for the basis as to how to proceed. Just my $.02.
Good luck!

[Chris Campbell]

One of the Lecomte Northeast 38's, Agave, was blown over a coral reef in the Bahamas a few years back, and had the hollow part of her keel dragged violently over the coral and badly scored. As the boats were laid up in two halves and tabbed together, the amount of glass along the centre joint is prolific, and the boat was towed off and sailed back to Florida without mishap (there was a small leak that the bilge pump took care of).
http://www.lecomteowners.com/index.php? ... &Itemid=41
http://www.lecomteowners.com/%20index.p ... view&id=69

Hal Roth's Spencer 35, Whisper, was blown ashore in deep southern latitudes prior to their rounding the horn - it had a huge gash torn out of the side of the hull - but all the damage was done to the hull, the keel (with a large hollow) survived relatively unscathed.

I guess my point is that there are lots of parts of our boats that would be negatively impacted by running into something solid, and trying to strengthen each of them in turn will result in a rather heavy boat that you probably won't enjoy!

[Pinching]

One other thing to be aware of is how your boat is blocked on the hard. Yards will sometimes block the keel fore and aft -- primarily to take the ballast (and hull) weight and stabilize against toppling with hull poppets. Advise your yard not to block under your sump, and only under the ballast. Else over time, at least on my boat, the plastic sump will deform a bit.

P