balsa core or not?

[steveandreina]

I have a 2009 23" C-Dory Venture. I was taking off the swim step the other day and plan on mounting a Kicker motor there. I am trying to tell if this boat has a Balsa core or if its compressed fiberglass. I did not see any trace of wood on the screws that I took out. Does anyone know?

 

[thataway]

There is a 3rd possibility--that is a foam core. Foam is of varying density and composition. In any case, the hole should still be epoxy sealed with under cutting, then filling the periphery with thickened epoxy--re-drill the hole. The epoxy also forms a point which will avoid crushing the core.

 

[hardee]

I have a 2009 23" C-Dory Venture. I was taking off the swim step the other day and plan on mounting a Kicker motor there. I am trying to tell if this boat has a Balsa core or if its compressed fiberglass. I did not see any trace of wood on the screws that I took out. Does anyone know?

Would there be foam or balsa coring in the transom? I'm assuming you are taking the swim step off of the transom so the screws are coming out of that.

Just asking. I thought the transom would be solid fiberglass or maybe a wood core. (Definitely showing my ignorance here

Harvey
SleepyC :moon

 

[Foggy]

Wanna se some hull foam core and a transom balsa & marine plywood sandwich?

Go to my photos under WB Nod, second group.

Aye.

 

[hardee]

Corecell foam sandwiches left and center; Balsa and marine plywood sandwich right.
Center and right: Atlantic 42 catamaran
Right: Saber 28 Offshore transom plug, "Windigo"

Should read
"Center and left: Atlantic 42 catamaran

Hi Foggy. I have looked at those but had a hard time figuring which was which.

No C-Dory plug though.

Harvey
SleepyC:moon

 

[Foggy]

Hi, Harvey.

No, no C-Dory plug tho my 26 Venture was a core cell laminate (FG) something
like the center and left samples.

The powerboat transom plug was definitely all beef; a real big boy that ran with
the big dogs.

Aye.

 

[thataway]

SleepyC[/b] :moon

Yep, some of the C Dory line have foam core in the transom. My Tom Cat definitely did, and some have told me that some of the Ventures do.

 

[Foggy]

If memory serves me, the center plug was the cat hull.
The gray plug on the left was the cat bulkheads, deck, pilothouse.

Wondering the strength of these, one afternoon my bro and I took turns with
a wood splitting maul to each and could not break one; only a few nicks and
scratches in the outer layer. Tho not a true test for sudden impact, we agreed
the stuff was pretty tough.

Didn't come up with a method to test slow grinding thru the outer skin into the
core which would be NG. Some discussion of benefits of open vs closed cell foam
in case this were to occur. Concluded either was better than balsa if exposed to
water.

She slept real nice.

Aye.

 

[steveandreina]

Thanks for all of the replies folks. Just heard back from the Manufacturer in Bellingham and they confirmed it is a foam filling.

 

[colbysmith]

Resurrecting this short thread to find out if anyone definitively knows what the core is under the bilge sump? The area I'm speaking of, is on a 2007 CD-22 (Midnight Flyer), at the transom, between the fuel tanks, right in front of the bilge drain plug. This is a recessed area where the bilge pump is located. I ask, as one of the projects I just did is pulling out a bilge pump and float switch, and replacing with a new pump with an internal float switch. And as long as I was at it, pulling out my second pump to clean up and remount. Both pumps I drilled out the area where the screws would go to hold the pumps down, and then filled with epoxy to screw in to. Here's where it gets interesting. One of the screws was stripped and had pulled out some. When I drilled larger holes into the area, I got some moisture. Sort of like squeezing out a sponge. Not much, but still wet. However, the layers between the two thin fiberglass layers did not appear to be wood, but perhaps some more fiberglass, or something that appeared to be solid, yet not as hard as the fiberglass. My transom is dry. (Where I removed my two transducers and re-embedded the screws in epoxy.) I decided to drill out a larger, 1" plug in the center of my bilge sump, and again got some moisture. I only drilled thru the top layer of Fiberglass, and it almost seemed like another fiberglass layer under that. I did not go any farther, as I did not want to end up drilling thru the hull. Patched the hole and not much more I can do as we head into more freezing weather than decent workable weather. At this point in time, I don't think there is a serious water problem, but rather maybe just some wetness that has come in thru the earlier bilge pump mounting method. But it sure would be nice to know exactly what material is in between the top and bottom fiberglass layers, and if there is a recommended way to dry it out. Colby

 

[ssobol]

I have a 22. My guess is that the bilge sump is formed by not having any core material there. The drop off caused by leaving the core material out makes the sump.

FWIW, on my boat the bilge drain was kind of high up. This would leave water in the sump that was too low to drain out, but not high enough for the pump to get. I added a new drain that is as low as I can make it and gets a lot more water out of the sump.

 

[colbysmith]

This sort of makes sense to me. After reading earlier comments in this thread, I thought perhaps some kind of hard foam was between the layers of Fiberglass. It's really hard to tell from the 3/8" or 1" holes I drilled. I suspect the moisture is in between the layers from the original bilge pump screw holes. Colby

 

[thataway]

Sunbeam looked into this—Her boat was a little older, I believe, but she found a thin layer of core under the depression. My recollection is that she removed that core. In all of my boats there have been screws in the areas with the depression—and If they were in the true hull bottom, they would have protruded thru the bottom. I have over drilled and filled these holes. Put the base of the bilge pump in with epoxy or 5200.

 

[colbysmith]

Thanks Bob, I was hoping you would reply. :wink: And I wonder if we'll ever hear from Sunbeam again? For now, I just used some very small screws and reinstalled into the overdrilled and epoxied holes. I did put a small dab of adhesive silicone as well on the pump basket bottoms, just so if I ever want to pull them out for cleaning or whatever, they would come out easily. Still not sure what that inner core in that bilge sump area is. But hope the moisture I had in that area is nothing major. I really can't do much more with it right now with temps below freezing. Perhaps a late summer project next year. That or find and pay for a heated shop big enough to put the boat in. Colby

 

[Jack in Alaska]

FYI.............my CD has been repaired and is back outside, after 3 months in a heated shop. Now totally shrink wrapped. Just beat it to death with $$$$$.($520)
The water squirting out of an 1/8" hole in the transom came from the totally soaked 2 layers of 3/4" plywood bonded and fiber glassed in. The boat hull was wet also towards the back of the boat. It was vertical grain balsa wood totally water soaked.
All of the plywood and balsa wood was removed after stripping the inside of fiberglass. It then set, bow up, in the heated shop for almost a month while he worked on other items on my boat as well as other boats. He used treated plywood in the transom and a synthetic product (name???) in the hull.
He beat on my boat with $1000 bills until it was fixed and he used up 20 of those. He reassured me that he would feel safe with his family in my boat out in the rough Cook Inlet so I will do the same next spring.
My boat has an Armstrong bracket with 12, 1/2" stainless bolts sealed up poorly and poorly set with just washers inside which crushed the inner fiberglass. There are now 10 bolts with a strip of 3/8" by 2" aluminum drilled out to back all of the bolt heads. A much better method.
The repair man feels that the water entered in the old bolt holes which were all right at or well below the water line.
He also said that the drain plug was poorly seated/sealed and too high causing the water to set in the bilge even with the bow raised up very high when parked. He installed a new plug housing and set it as low as possible.
The walk around deck on the port side of the cabin came apart and had to be rebuilt and fiberglassed. Some of the gussets on the hull under the gunnel had fractured also.
I love my CD boat but I am very disappointed in the quality of construction overall. My 22' 1983 model had much better workmanship and is still in use and was in excellent shape until it was stolen this summer.
Seal up all holes drilled into the hull to save you money and heartache dealing with it.
Jack