Another non-owner but thinking. Can anyone here tell me whether the hull and deck layup of the CD22 incorporates solid glass in way of penetration points for fitting bolts and thruhulls? You'd hate to think these holes were drilled through the balsa core. (Beware: this is probably the first of many more questions!)
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Possibilities of core saturation?
- Thread starter Spike38
- Start date
starcrafttom
Active member
yes they are, drilled in to the core. All the screws in the deck are into the core. amount of sealing is dependent on the boat. Others can tell you more about how the core is built up and methods to stop the spread of water.
I cannot say how much of the boat deck has plywood vs balsa core. Many builders use plywood under the way of cleats etc. There should be few if any screws--for the most part items are thru bolted and backed.
I agree that cabin house elements in boats in dry environments will probably be "OK" with no solid glass/epoxy. But there is danger of crushing the core, if the bolt is tightened too much, and in my opinion, screws should not be used.
But in high load deck areas, or areas subject to water saturation or intrusion, it is best to drill out the core, undercut and fill with epoxy. In the hull/and transom, this is essential.
I agree that cabin house elements in boats in dry environments will probably be "OK" with no solid glass/epoxy. But there is danger of crushing the core, if the bolt is tightened too much, and in my opinion, screws should not be used.
But in high load deck areas, or areas subject to water saturation or intrusion, it is best to drill out the core, undercut and fill with epoxy. In the hull/and transom, this is essential.
Warren,
Yes, if the under cut is adequate. If you just coat the edge of the hole, then there is little protection. If out undercut by 1/4", and fill with epoxy, then this will prevent compression.
On the other hand, I have done "autopsies" on some 30 year old boats with plywood on the foredeck where the main cleat was, and there was no compression damage, and minimal water damage. In these cases there was excellent sealing of the hole with a bedding compound. So if there is plywood, it seems to be adequate. The question is does C Dory use plywood in the position where cleats are installed?
For my windlass, I backed the entire area under the windlass with an aluminum plate, and did minor undercutting of the holes. This seems to be satisfactory. This area was balsa cored in both the Tom Cat and CD 25.
Yes, if the under cut is adequate. If you just coat the edge of the hole, then there is little protection. If out undercut by 1/4", and fill with epoxy, then this will prevent compression.
On the other hand, I have done "autopsies" on some 30 year old boats with plywood on the foredeck where the main cleat was, and there was no compression damage, and minimal water damage. In these cases there was excellent sealing of the hole with a bedding compound. So if there is plywood, it seems to be adequate. The question is does C Dory use plywood in the position where cleats are installed?
For my windlass, I backed the entire area under the windlass with an aluminum plate, and did minor undercutting of the holes. This seems to be satisfactory. This area was balsa cored in both the Tom Cat and CD 25.
Thank you for the responses. Yes, in the absence of anything more solid than balsa I'd be concerned about compression as well as water migration, also. But I have no idea how substantial the fiberglass "bread" in this sandwich is, either. Anyhow, it appears C-Dory does it the way most builders do.