Boat Smell and the Hidden Bilge on an Intrepid 9 Meter

[keneasley]

I bought my 1979 Intrepid 9 Meter about 2 years ago.
Overall she's been a fine boat except for a persistent bad smell. Sort of like old mildewed rotten wood.
After much cleaning and sealing of leaks the smell persisted.

Reading a different sailboat forum I came across a write-up concerning a hidden bilge.
My Intrepid has a pan type, shallow bilge that runs from the head area back to a few feet forward of the engine area.

This Spring a leaking seacock for the galley sink drain (aft of the pan bilge) caused a fair amount of really bad smelling water to find it's way into the pan bilge. How it got into that bilge was a mystery to me.
After having the boat hauled and the seacock replaced I cut a hole in the cabin sole and found that there was a bilge that was aft and below the pan bilge and that had been inaccessible until I cut the access hole.

This picture shows the newly cut access hole fitted with a white access panel. The new hole is aft-most in the cabin sole and right-most in this picture.

Bilge_Project_b16.JPG

This picture shows the new access hole and the bilge hoses that route through the hidden bilge.

Bilge_Project_b14.JPG

This picture shows the view from within the hidden bilge looking forward at the pan bilge.
The bad smelling water got into the pan bilge from the hidden bilge through one of the holes cut for the bilge hoses.

Bilge_Project_5.JPG

I then performed several cleanings and scrubbings and got into the hidden bilge, which runs underneath the pan bilge as much as possible. This included cleaning using regular bilge cleaners, vinegar and water, baking soda and water, lots of filling with water and pumping out. Whatever I could do to get cleansers and fresh water in and around that hidden bilge area. Then a final cleaning with lavender scented Fabulosa floor cleaner and a final rinsing.

I'm glad to say that 90% of that bad smell is gone.

I'm posting this for any other Intrepid 9 Meter owners out there.

The boat undoubtedly had that foul smelling water stuck in the lower / hidden bilge since she was first launched. A poor design for a bilge in my opinion but one that I have mostly remedied. Some parts still cannot be accessed directly but at least I can now get cleansers and fresh water in and out of the entire bilge area.

Please let me know your comments or ideas for improvement.

[gonesail]

good work. I'm not at all fond of shallow bilges. my CD30 has an almost 24" deep bilge .. all accessible from a single teak inspection port.

[Jim Walsh]

I bought my 1979 Intrepid 9 Meter about 2 years ago.
Overall she's been a fine boat except for a persistent bad smell. Sort of like old mildewed rotten wood.
After much cleaning and sealing of leaks the smell persisted.

Reading a different sailboat forum I came across a write-up concerning a hidden bilge.
My Intrepid has a pan type, shallow bilge that runs from the head area back to a few feet forward of the engine area.

This Spring a leaking seacock for the galley sink drain (aft of the pan bilge) caused a fair amount of really bad smelling water to find it's way into the pan bilge. How it got into that bilge was a mystery to me.
After having the boat hauled and the seacock replaced I cut a hole in the cabin sole and found that there was a bilge that was aft and below the pan bilge and that had been inaccessible until I cut the access hole.

This picture shows the newly cut access hole fitted with a white access panel. The new hole is aft-most in the cabin sole and right-most in this picture.


This picture shows the new access hole and the bilge hoses that route through the hidden bilge.


This picture shows the view from within the hidden bilge looking forward at the pan bilge.
The bad smelling water got into the pan bilge from the hidden bilge through one of the holes cut for the bilge hoses.


I then performed several cleanings and scrubbings and got into the hidden bilge, which runs underneath the pan bilge as much as possible. This included cleaning using regular bilge cleaners, vinegar and water, baking soda and water, lots of filling with water and pumping out. Whatever I could do to get cleansers and fresh water in and around that hidden bilge area. Then a final cleaning with lavender scented Fabulosa floor cleaner and a final rinsing.

I'm glad to say that 90% of that bad smell is gone.

I'm posting this for any other Intrepid 9 Meter owners out there.

The boat undoubtedly had that foul smelling water stuck in the lower / hidden bilge since she was first launched. A poor design for a bilge in my opinion but one that I have mostly remedied. Some parts still cannot be accessed directly but at least I can now get cleansers and fresh water in and out of the entire bilge area.

Please let me know your comments or ideas for improvement.

Great bit of detective work. Well worth the effort. I’m sure this info could prove invaluable to another Intrepid owner with the same issue.
On a side note I remember seeing one of the first Grampian 28’s in 1975. She was quickly readied for a racing campaign in the Off Soundings events.

[Paul D.]

Preventing boat smells from bilge, head and mildew odors is a high priority for me as I have worked on a lot of smelly boats and want my family And guests aboard to enjoy the experience. I look at it through several strategies: ventilation, cleaning regimens and winterizing procedures. Then, also some toasting to the gods that she stays fresh and clean under my watch.

Don Casey books have good advice on this and your finding of the bilge without access will be a real help to other similar boat owners. Thanks!

[keneasley]

Jim,
Thanks for that info RE the Grampian 28. That boat does looks similar to mine.
Ken

[keneasley]

Paul,
Thank you for that info. I'll get one of the Don Casey "This Old Boat" books.
It took me about 4 years to get my former boat (Sea Sprite 23 weekender) odor free.
That was a simpler boat with a lot less woodwork.
Ken

[Keith O]

Hi Ken... pleasure to meet you. We've had our Intrepid 9M for four seasons. I replaced bilge hose this spring and didn't encounter an obvious second chamber, so will need to look again next time I'm aboard. Nice job with your mod and write-up. Our original bilge covers are weakening so will need replacement soon, so I'll be in there myself in the near future.

Ask any questions.you like and I'll answer as best I can. I've done some things but have many, many still to...uhh... experience for myself.

Best,

-Keith
S/V Silver Lining

[keneasley]

Hello Keith,

I'm in Fairfield. Maybe sometime after COVID we can meet up.

The bilge covers in the cabin sole on my Intrepid 9M were delaminating and in rough shape.
Rather than using wood I went with "King Starboard". I bought them in white with a nonskid surface and ordered them precut and beveled and had only to drill a 1" diameter hole in the center of each one to facilitate removal. For the one in the head area (which is diamond shaped) I bought the King Starboard precut as a rectangle and then used a woodworking hand saw to cut each end diagonal. I used the original as a template. I filed and sanded that one smooth after making the cuts. Very easy to do.

Vendor was: boatoutfitters dot com

Dimensions for the two main salon boards (about $70 for the two) were:
White/White King Starboard Anti Skid Plastic Sheet
Qty: 2 Thickness: 1/2" Length: 15 1/4" Width: 7 9/16"
Roundover Edges: 1/16" (One Side) Radius Corners: None (Square)

Dimensions for the head area one (about $55 for the one) was:
White/White King Starboard Anti Skid Plastic Sheet
Qty: 1 Thickness: 3/4" Length: 20 1/2" Width: 10"
Roundover Edges: 1/8" (Both Sides) Radius Corners: None (Square)

They fit perfectly. You may have the same size. They offer different colors.

Ken

[Keith O]

Great to 'meet' you Ken and thanks so much for the additional cover details and write-up. Would definitely enjoy getting together to see your Intrepid (and vice versa) when we can be within a bilge length of each other without concern.

We definitely have the second chamber. Next task is to see how much nasty water lies within. Maybe that's a springtime job

[Dave H]

I have been sailing my I 9M "Sandpiper" since 2015, in northern Wisconsin, on Lake Superior. She has always been a freshwater boat, and very sweet smelling. I have always wondered what is under the pan. Thanks for investigating and posting. If there was any water there, I would expect winter damage, but none to this point. Very happy with this boat. Very well suited to my area, and situation. Dave H.

[keneasley]

Hello Dave H

Thanks for the reply and good to know there is an Intrepid 9 Meter out there that smells sweet.
Maybe the freshwater life has something to do with it.

The water here in Long Island Sound can smell bad even when it's not inside the boat.
Sometimes getting it on your clothes means that they'll smell terrible as they dry.

A bit more info on the 9M bilge set up -

On my boat the diesel engine is on a large pan. (The engine is relatively new 2006 Vetus 16 HP that the previous owner had professionally installed - the receipt said "...modify engine bed...").
This engine pan is above the bilge area.
The bilge area is below the "pan bilge" described earlier.

So any water, oil, etc. from the engine will flow into the bilge and be trapped under the "pan bilge".

Also any water from a stuffing box type shaft seal or any water that gets in aft of the engine will flow into the bilge below the "pan bilge"

The only way on my boat that water can get up and into the "pan bilge" is through the holes for the bilge pump hose shown in the earlier pictures. And that will only happen when there is enough water in the bilge to reach that height. That water would then be visible and could be pumped out with the bilge pump. So, I guess that this would not create an odor problem if the water was clean and there was some turnover of the water. I think my problem was that the water was dirty and stagnant for many months/years.

I took a picture of the area just forward of the engine which shows the bilge where any water from the engine would enter. Those two hoses are the bilge pump hoses. The green area in the gap is the bilge where the water flows into.

I'm curious if you and other Intrepid 9M owners have a similar set up.

Engine_Pan_Gap.JPG

[Dave H]

Ken, Thanks for the photos. Looks the same as "Sandpiper." I have found that everything flows to the bilge pan. While decommissioning this fall, I first pumped, then wiped, the "bilge pan" dry. Then applied anti freeze at the engine shaft thru hull, and next at the motor pan. With both of these locations, the anti freeze flowed to the "bilge pan." I want a higher capacity auto electric bilge pump, so I need to be sure to have my fastener holes to the old bilge pump properly sealed. Really hope I can accomplish that in a foolproof manner. Are there any old fastener holes in your "bilge pan" that could be leaking pan water to the bilge below? (Just a thought.)
Dave

[Steve Laume]

On Raven, CD-30, I do have a shower pan above the bilge. That shallow pan collects water from the head/shower area to keep it out of the bilge. There is a drain plug in the aft end that when removed will allow the water in the pan to enter the bilge. You need far more capacity and depth than that little pan to make a proper bilge. Raven has two access hatches in the cabin sole. One is at the aft end of the shower pan, which also allows you to get to the bilge. The other is right in front of the engine which gives access to the top of the holding tank.

I really can't imagine that Cape Dory didn't provide access to the bilge. How would you install a pump or clean it out? Maybe the 9M without the hatch was built on a Friday and someone just didn't get to it, Steve.

[Dave H]

Thanks for your insight Steve, but I don't think your Friday Theory holds water. But my bilge pan does. The main source of water to my bilge is melt water from the cooler. The auto electric bilge pump is installed to the pan bottom. As I tried to describe above, other possible sources such as the motor shaft drip bearing and motor have been tested with anti freeze into a dry pan. All anti freeze going to the pan. This boat has never been south of Minneapolis, so I think any water below the pan would have made itself evident over winters...
I have found the I9M to be an exceptionally satisfactory sailboat. Lots of little design features that show a lot of thought went into this design, to quote the owners manual.

[keneasley]

Updates to my original post.

The "built on a Friday" comment may have something there. Continue reading if you're interested.
I'd appreciate any comments as to solutions.

Digging deeper into the hidden bilge problem I found an article about a home-made "Dry-Bilge" system and decided to give it a go over the winter. Read this for the source: https://panbo.com/a-dry-bilge-for-50/

Now many might say that the bilge should not collect water in any event but until I get everything 100% sealed it will.

The bilge pan on my boat has limber holes at both the fore and aft ends.
I suspect these are there to allow water into the pan from the inaccessible areas of the bilge.
The problem on my boat is that the bilge extends below these limber holes.
Perhaps the boat was built on a Friday and the lower part of the bilge should have been filled in with fiberglass or in some other way sealed and raised so that the water would not settle below the bilge pan limber holes.

I built the Dry Bilge system using a readily available small pump, timer, tubing, etc. I hard wired it straight to the House battery with a fuse. And a couple of sponges and fittings very similar to the article referenced above. Parts list below.

See here the limber hole and the bilge below it. The limber hole is the lowest hole and the black area is the former "water line" of the hidden bilge.
This is the aft end of the bilge pan before I added the Dry Bilge.

Bilge_Project_4.JPG

See here the aft end with the Dry Bilge pick up.

Dry_Bilge_5_pick_up.JPG

For the forward end of the bilge pan I had to cut an access hole into the cabin sole.

Dry_Bilge_7_access.JPG

Continued ...