CD-25 Bilge Design

[cbadmin]

From: MichaelOnTheClaraMae (Original Message) Sent: 1/8/2003 12:58 AM
On the CD-25, I am concerned about the design of the below-deck compartments and the location of the bulge pump. Under the cockpit deck, there are six compartments as shown here. They are:

1) Starboard side stowage. The red trim tab pump is located here.
2) Port side stowage. The macerator pump for the holding tank is located here along with the raw water through-hull, valve, and pump.
3) Rear bilge area centered on the transom. The drain plug is located here.
4) Holding tank compartment in the center.
5) Bilge pump compartment which is the smallest shown in the center.
6) Fuel tank compartment which is the largest area forward.

As you can see, the bilge pump is isolated from the majority of the under-deck space in a small compartment of its own. Aside from a one inch space between the top of the dividing walls and the underside of the deck, water cannot get to the bilge pump from the other compartments. In other words, water will get to the bilge pump once the other compartments, which are large, completely fill and spill over the top.

I may be missing something, but, I don't see this as a good thing. Say for example, the hose to my raw water wash down in the port stowage compartment fails. That compartment will completely fill with water until I open the hatch and dip it out with a bucket. Or worse, suppose I take a major wave over the side or transom. The rear access panel will most certainly be displaced and the rear bilge area will fill with water. Both starboard and port stowage areas would likely fill as well through the hose and cable openings located in the aft corners. Regardless of how water gets in there, it's going to stay because it can't get to the bilge pump.

I am considering cutting 1" or 2" holes on both ends of the bilge pump compartment close to the hull and finishing the cuts off with some gel-coat. I may do the same to the aft bilge area if I can get to it. This would at least tie the open areas together and allow them to drain to the pump. The tank areas don't bother me since the tanks themselves already fill the void.

Comments and suggestions would be greatly appreciated.

Michael on the Clara Mae

From: Sawdust Sent: 1/8/2003 1:10 PM
Michael,

That is really strange. On the 25s at the factory with tanks and equipment not yet installed I noticed some half-moon limber holes between all of those compartments... I think!! I'll be at the factory in a day or two and will check again. Les has some photos too but I don't have them available. EQ has a 25 that will be in the Seattle boat show, and I'll look that one over and let you know.

Sawdust

From: MichaelOnTheClaraMae Sent: 1/8/2003 2:04 PM
Thanks Sawdust. Maybe that was the intent and the cuts were never made. I look forward to hearing back from you.

Thanks again,
Michael

From: stevej Sent: 1/9/2003 12:52 PM
Michael the bilge design on the new 25' is a little different than my 95 but it's close.
Shearwter does not have the holding tank located in the back deck (it's in the cabin) so that area serves as the bilge. There are no holes between it and the side lockers or the battery locker (in front of the gas tank) so I just hand bail any water that may get in but they stay very dry for the most part. Not sure I would want the bilge flowing in these areas because it would limit what you could store and be difficult to get dry if water did get in.
I went down the same road as you in thinking about the side lockers flooding, in my case there is a through hull for the deck drains/scupper inside. I minimize the possibility of failure by replacing the connection hose for the drains every year, check the hose clamps monthly and use bronze through hull fittings so the chance of a failue is very small.
After doing some serious thinking about taking a load of water over the transom the impact of the side lockers filling becomes a minor issue compaired to the amount of time required to drain even 6 inches of water from the rear deck (I guess that at least 10% would end up in the cabin if the door were shut). 6 inches of water would be over 100 gallons or 800 lbs.. An additional 800 lbs in the rear could push the transom mounted scuppers below the water line so unless your making headway to suck the water out the bilge pump would need to evacuate the entire pool.

To help minimize this problem some I'm going to install an additional bilge pump in the cabin and add a couple of 2" x 6" side scuppers about mid-point in the deck. This would drain water far faster than any bilge pump we could run.You still run the risk of these becomming submerged or the stoppers becomming jamed open but it's the only way to move a large volume of water in a short amount of time off of the rear deck.

Hope this is of some help.

steve

From: MichaelOnTheClaraMae Sent: 1/9/2003 10:41 PM
Steve,

In my case getting water into the other compartments from the bilge pump compartment is not the problem because of where it is located. Right now the only way water would get to the bilge pump compartment first is for me to unscrew the inspection plate and pour water in it. I'll be surprised if the cuts Dusty is talking about were not left out by mistake on my particular boat.

My boat came with a second bilge pump in the cabin which sits next to the through-hull for the head. The door on my 25 is pretty stout and there are no weeps into the cabin. As long as the door held up, I think I could just about fill the cockpit without much water getting into the cabin.

It sounds like your existing scuppers go through the deck and out below the water line. I have two 3" round scuppers in the transom just above the water line right now. Adding more is always an option but I still want to ensure the under deck spaces will pump out if they begin to fill with water whatever the reason.

Michael

From: MichaelOnTheClaraMae Sent: 1/10/2003 11:20 AM
I received a call today from Cam, the C-Dory production manager for the CD-25 shop. He confirmed the holes between the compartments on my boat should be there and were apparently omitted by mistake. He agreed with the idea of cutting a 2" hole close to the deck at either end of the bilge pump compartment and the aft bilge area. This would tie everything together with the exception of the fuel tank area. I don't really want to chance cutting into the tank itself. Besides, the tank takes up 98% of the volume in this area.

Michael on the Clara Mae

From: MichaelOnTheClaraMae Sent: 1/24/2003 6:34 AM
More developments:

I was hoping to have some pictures to help explain this but they will have to come later. As planned, I cut an opening in the stringer between the starboard stowage area and the bilge pump compartment and out came about a half cup of water! This had me scratching my head.

After completing the cut, I could see there is about a 3/4 inch space or void at the bottom of the stringer between the glass. In other words, the plywood that makes up the core of the stringer was held up 3/4 inch off the hull and then glassed in. In making the cut on the port side, it was similar.

Why this is I am not sure but the void at the bottom of this piece does not really bother me. "Stringer" is actually the wrong term to use because these vertical pieces that separate the compartments don't really support the deck. They appear to be there merely to hold the tanks in place. Void or no void, they are plenty adequate for that. But how did the water get in there?

After crawling in deep and with the help of a mirror, I saw that the factory did indeed drill a 1/4" hole at the bottom of the the dividing walls (and through this void) of the rear bilge area into the stowage areas on both the port and starboard sides. Because the natural slope of the boat is forward, water has been entering these voids and moving forward with no way out... until now .

This is actually a relief to me because I know the water is not coming in through the hull or some other vital part of the boat. So, my game plan has not changed. I am going to make those 1/4" holes in the rear bilge area 2" to match the ones I have already made forward. I want any water that gets below the cockpit deck to flow freely to the bilge pump. Then after getting the void and plywood core in these stringers good and dry, I will fit some small blocks in the void openings at the bottom of each side of my new 2" holes (four locations). Installing the blocks with some 5200 should seal them for good. Then I will sand and paint the cut edges with gel coat.

This may be a little much for a dividing wall installed there to hold the tank in place. In fact, the plywood core could probably rot out and the glass on both sides of it, which is plenty thick, would likely hold up fine. One real problem I see with this however, is with the water and saturated wood core freezing and maybe breaking the glass. Besides, it is a brand new boat. I don't even want water in the core of my beer coaster .

In fairness, I have not talked to Cam about this problem (I need to find his number). I do plan to call him as I know he would likely be concerned with it. And I could take it back to my dealer for repairs. But besides having a "if I do it myself it will get done right" complex, it is 500 miles to Crystal River, FL. I could have this fixed in the time it took me to get down there and back.

I am writing this off as part of the shake-out phase and an exercise in getting to know a life long companion.

Michael on the Clara Mae

From: MichaelOnTheClaraMae Sent: 1/24/2003 8:55 PM
Here is a picture or two.

From: Mike Sent: 1/24/2003 9:10 PM
Michael -

That had to be a mistake on those 25's, both yours and Swanny's, to not seal the balsa core with something. Maybe they figured it would dry out before the wood was soaked enough to start rotting. It sure would have been simple for them to glass it over.

Mike

From: Swanny Sent: 1/26/2003 10:16 PM
Michael,
Thanks for the pictures and insight on the bilge area drainage. Not sure if my "version" of CD25 is same. Mine was kicked out of the factory late Sept '02. When was yours? I see a channel running fore/aft under the gas tank that seems unrestricted back to one of the 2 bilge pumps behind the tank in front of the holding tank area (mine is empty, no holding tank). I heard they moved that pump to where mine is because they found the water collected better in the new area. Still have the one under the cabin step next to the demand fresh water pump. I haven't fully related on my boat where you drilled the 2" hole.

Say, is there a thread running on the CD25 and its performance information and all? I'd like to contribute what I've learned like I did on the C-DOG site.

Thanks,
Steve

From: Swanny Sent: 1/26/2003 10:21 PM
Another comment on the bare balsa core exposed for the 4 hatch cutouts. Really, those exposed areas should never get wet normally. Once the seal is correct on the hatch edges, the only way for water to reach the balsa is to fill the 14" of space from the bottom of the boat--and hopefully, the bilge pumps would have prevented that. Plus, how would water get in there in the first place--that area should be sealed from all external weather unless the drain plug was left out. Now humidity might be a concern, the balsa could absorb that. But here in the soutwest So. Cal., are humidity is quite low most of the year. I think I'm trying to rationalize why I didn't seal the balsa core BEFORE I sealed the hatches down so perfectly with Boatlife. Don't want to tear them apart again...

Steve

From: Mike Sent: 1/26/2003 10:28 PM
Steve -

Good idea on the performance info. It would be great to start a new discussion specifically for the CD 25's on the General message board. There is already some info about the CD 19 on there, and your contribution would fit real nicely in a thread right next to it. Don't let my wife see it, though. She really thinks we need one of those 25's.

Thanks for thinking of it.

Mike

From: Mike Sent: 1/26/2003 11:24 PM
Steve -

See this note in the Setup Talk section for some more info about the General message board.

Thanks

From: MichaelOnTheClaraMae Sent: 1/27/2003 5:44 AM
Steve,

My 25 was shipped late Novemeber 2002. It sounds like mine and your is set up the same as far as where the under-the-cockpit-deck is located. The difference is that I don't have the "channel" fore and aft you speak of.

If you look here, you can see the three smaller compartments down the center. Starting at the transom there is the Rear Bilge area where the transom plug is. You are right in that the bilge pump used to be located here on some of the earlier models. The factory drilled a 1/4" hole through both the starboard and port sides of this compartment. I have since made those 2" to allow the water to move and to seal them.

Next you see the Holding Tank. Forward of that is the small compartment where my bilge pump is located. I cut a 2" hole in both the starboard and port sides of this compartment as well.

Michael

From: MichaelOnTheClaraMae Sent: 1/27/2003 7:25 AM
Steve,

If I were you in your climate, I would not ruin a good sealant job on the hatch frames just to seal the balsa edges in the deck cuts. You are right that water should never touch them, especially now that you have the deck frames sealed.

Michael