Cabin hull screws

CDory23 · Posted: Tue Nov 11, 2014 7:19 pm Post subject: Cabin hull screws

Hi all, Last couple times I've been out I've gotten some water onto the floor of the cabin. Melted ice from the ice box leaked out of the fridge and settled to area underneath the stove/sink cabinet. It was only there for a few hours and I'm wondering if i need to worry about the screws that secure the cabinet to the hull floor and other screws in the area that are the holding potable water line secure etc.... They do not look like they were sealed and I don't want to have any hull rot. Do I need to go the whole undercut epoxy route and then put screws back in? Have others ever had water in this area and is it something to be concerned about?

Thanks

journey on · Posted: Tue Nov 11, 2014 7:39 pm Post subject:

My comment for what it's worth.

The cabin sole of Journey On filled with salt water when we first used it; a result of a factory screw up. Bilge pump emptied the cabin, factory resealed the anchor locker, etc, etc. There was several hours of wet floor for a couple of cycles.

So, I've pulled a number of the cabinetry hold down screws over the years and there is NO SiGN of water ingress, let alone rot.

I'd take a deep breath and enjoy your boat. Fresh water for a short period of time isn't even going to corrode the screw heads.

Boris

thataway · Posted: Tue Nov 11, 2014 10:30 pm Post subject:

I agree that there is no worry from a brief immersion. In the long run it is best to have the screws better sealed. The best is drill out, slightly undercut, and then drill new pilot hole, and put in the old screw. Several issues here. Most of the boats had cadmium pated "L" brackets and screws--which rust easily. You do have the vulnerability of screws.

The easiest thing to do, is to pull the screw, eliminate the "L" bracket and screws from the wood also. drill out the hole enough to fill with epoxy, and then over this area, put a tab of fiberglass cloth and epoxy. You have eliminated the screw in the hull, the hole in the hull, and the "L" bracket.

The down side of this, is it might be slightly more difficult to remove this tab if you want to rebuild the cabinets. I don't see this as an issue. The epoxy/cloth (I used some triaxial cloth I had in stock), takes a very short time--have to sand the area where you are putting the tab, and be sure it is clean. Do every other tab at first, or do some tabs between the "L" brackets, and then pull the screws, and tape over them--so there is no chance of the cabinet moving.

Sunbeam · Posted: Wed Nov 12, 2014 1:50 pm Post subject:

I agree that it's best not to have screws going straight into the structural hull core with no protection. Granted, it's not a place that is likely to "soak" in water, but I just find it to be something I don't want to worry about (so I changed mine).

One thought if you are going to tab: As Thataway said, it can make it a pain to remove any cabinetry. Not that you are going to do that every day, but why remove the option ('course you could always cut tabbing, but...). Also, I'd be a bit "meh" on the idea of bonding tabbing to the top (white) surface of the Decragard (you could cut away the top layer, but that's more work again). So if I were going to tab (and I may in some places), I think I would do it how I have seen it done on Albin boats (just for one example). Essentially, you lay up the tab and bond it properly to the hull (sole) as you would normally tab. But, you don't bond it to the "furniture." Instead you lay it up against the furniture, but keep it from bonding (tape, wax, etc.). So you end up with a "fin" of tabbing. Then you screw that to the furniture (which is not structural anyway). As such there is no worry about bonding to Decraguard, and things are removable/replaceable by undoing the screws (yet there is no penetration into the core).

I did something a little different (and less messy). It was a bit of an experiment, and if it doesn't work out, I can easily go to one of two "Plan B's" with no more work than I would have had originally. What I did was buy slightly larger, stainless steel angles (instead of the mild steel ones that were there). I removed the original angles, overdrilled and filled the holes into the core, and chiseled them off flat when in the green stage. Then I bonded the new angles to the sole with thickened epoxy. After that had cured I screwed their upper legs to the cabinetry.

The place I think that might conceivably fail is in the bond to the sole. If that does happen I will move to one of two "Plan B's." One would be to screw them to the sole into the epoxy plugs; or two would be to remove them and do tabbing as described above. Either of those would eclipse any "failure" of the way I did it already (and again, not structural). So far so good with Plan A, but it's early days yet.

thataway · Posted: Wed Nov 12, 2014 6:55 pm Post subject:

journey on · Posted: Wed Nov 12, 2014 7:30 pm Post subject:

Just out of curiosity and to keep from doing something useful, how are the one piece interior moldings now used fastened: brackets or tabbed?

Seems tabbing would be quicker and probably more secure.

Boris

ghone · Posted: Wed Nov 12, 2014 9:42 pm Post subject:

Hi Boris. My 2011. 22 has the molded interior. It is bonded full lenth to the hull, up the back bulkhead, where it meets the hull sides etc. ie. all the way around the galley part and dinette parts and floor.etc Not tabbed, but full length bonds. This makes for a very rigid cd 22! I was impressed on delivery, they could have done short tabs.
George

Sunbeam · Posted: Wed Nov 12, 2014 10:18 pm Post subject:

Lost Petrel · Posted: Wed Nov 12, 2014 11:15 pm Post subject:

I am going to go with Sunbeam on this one. I have done some refitting on boats and now try and create a solid tab that the cabinetry can be screwed to/through. The main reason is if I have to someday remove the cabinet to run wire or hoses, etc., it is a lot easier job requiring a lot less tools and time.

Sunbeam · Posted: Thu Nov 13, 2014 12:36 am Post subject:

I figured I'd post a photo of what Lost Petrel and I are referring to. This is an Albin Vega (sailboat, but they did this in powerboats they built as well), with the bulkheads out, but the tabbing "fins" still in place. (One happens to be white and one natural "glass" gold color). When the bulkheads go in, they are set flush to the "fins" and then screws go through the fins and into the bulkhead (or furniture).

This is arguably not as strong as full tabbing (fiberglassing to both surfaces), but it seems to have held up pretty well in these structural bulkheads, so in non-structural applications it should be completely fine, in my opinion. Just another way to do things.

In my case if I were going to make some of these "fins" of tabbing in my C-Dory (in place of the metal brackets), I would likely do something like put clear packing tape on the furniture (where the tab would land) and prep the hull for fiberglassing as per usual, then "tab" to the hull and up onto the clear tape. Once the glass had cured I'd loosen the furniture piece in question and pull the tape, then screw the remaining "fin" of tabbing to the furniture (as the angle brackets are) once it had fully cured. It's one way to tab the furniture in place but also keep it reasonably easily removable, if one so desires. Just one way of course, and simply a choice.

Sunbeam

Sunbeam · Posted: Thu Nov 13, 2014 6:54 am Post subject:

Too late to edit, but I should have mentioned I wouldn't make such comprehensive (long) tab "fins" as in the photo to fasten non-structural cabinetry/furniture in a C-Dory. Just short tab sections would be plenty, in my opinion. Those in the photo are for structural bulkheads, whereas the C-Dory furniture is basically "being held in place."

Sunbeam · Posted: Thu Nov 13, 2014 6:59 am Post subject:

thataway · Posted: Thu Nov 13, 2014 3:09 pm Post subject:

rogerbum · Posted: Thu Nov 13, 2014 3:27 pm Post subject:

When I was getting ready to sell my 22, I took the time to remove all the screws that held down the cabinetry. I had water in the cabin a few times and as a fisherman I often track water in on rainy days. I found the screws to be mostly dry after 8 years of use but there were some areas immediately adjacent to the screws that were moist. I got to dry wood in all cases with just a little bit of undercutting. All of the brackets on the floor were pretty rusted after 8 years. I took Bob's advice at the time and just tabbed in the cabinetry. I think very few people will ever actually remove the cabinets and if they do, it's usually for some fairly major modification. So IMHO, tabbing them in on both top and side makes the most sense. It's fast, it's easy and it's strong. With a dremel and cutting wheel, the tabs can be easily cut in seconds. If you repaint the cabin sole, the tabs look pretty decent too. Here's one I did inside of the galley cabinet. This view is looking down, the bracket you see if off the floor by a couple of inches.

CDory23 · Posted: Fri Nov 14, 2014 1:40 am Post subject:

Thanks for all the replies. The tabbing looks like a good option. I am very limited with knowledge of fiberglass fabrication/repair at this point. How well does the decreguard and cabinetry need to be sanded before applying cloth and resin? Luckily I have a tap plastics near me with access to all materials.

Also this only eliminates the cabinetry L brackets and screws. What about all the screws holding the potable water line is place?

I understand the process of overdrilling/undercutting, but on other posts I have seen the use of two epoxies to fill holes, is that necessary?

Thanks again