Hull to deck flange...what to do when it's broken and leaking water?

[rockhopper]

I seem to find all sorts of articles about how Pearson used an external hull to deck flange and how them banging into docks and the sort can break the flange, but no one has mentioned if or how this is fixable. So what can you do to fix this once it has happened?

My P30 has a couple of spots where the hull is now flush with the deck. Part of the fiberglass flange is broken off, there appears to be a piece of wood between the deck and the hull. My biggest issue is that when it rains, water comes in on the port side aft. I'm trying to seal all the leaks and keep the water out of the boat. Has anyone had any experience with this?

[azazzera]

I have a 73 p30. I took off the rubber rail and the plastic rail under that. I dremeled a wide notch between the hull and hull. Then filled with thickened west system. But the proper way would be to fiberglass the two together. It wasn't a demel it was a grinder.

[rockhopper]

I'm guessing it would almost be impossible to get the hull back to its original position but I'm trying to figure out my options before I do something that will cost me more time and work to get it like it should be. A previous owner looks like they attempted to put some 5200 on the inside of the joint in about a 4" spot but it still leaks.

[azazzera]

Nothing is impossible with enough time,money and skill. Lacking the skill I have patience. Come to think of it I don't have the money either. It sounds like you have to grind back some damaged fiberglass and reform the hull/deck flange. Find a good fiberglass guy or learn yourself.

[tac]

Preventing hull/deck flange damage: Use fenders!

Every type of hull/deck flange has its pros and cons, that's why there are some many different variations. One of the good points of the P30 external join is that it is totally accessible. I once worked on a 50' boat with inward turning hull/deck flanges, bolted together with 1/4" screws and nuts every 4-6". Removing 20' of these was a horror show. Most were inaccessible without removing joiner work, and others could be accessed only by feel since you couldn't see them.

I don't remember all the dimensions, and I don't have my notes and sketches here, so I'm working from memory. For the '78 P30, the flanges were put together with an elastic sealant, possibly a polysulfide like Life-Caulk. Then hard plastic insert sections, each a few feet long, were held over the joined flange, and drilled and countersunk every few inches through the insert, deck flange, and hull flange. Short (1/2"?) flathead stainless tapping screws (#8? #10?) were installed to hold it all together. The whole thing was covered by a PVC molded flexible rub rail, which snaps in place over the rigid inserts. The rub rail is a single piece, 70' or so, each end held in place at the transom by a hard plastic end fitting and tapping screws.

The inserts and rub rail are still available:

https://shop.hamiltonmarine.com/inet/storefront/store.php?mode=searchstore&search%5Bsearchfor%5D=233-r

Repairing leaks can be done fairly easily by 1) resealing the bad area, or 2) glassing over the mated flanges.

[tac]

RESEALING THE HULL/DECK JOIN

1. Find where the leak is. It's not that simple. Water tends to flow, so where you see the water in the boat is not necessarily where it is entering.
2. Remove the end fitting from the leak side.
3. Strip off the rub rail to the area beyond where the leak is.
4. Remove the tapping screws several feet either side of the leak.
5. Remove the insert(s) in that area.
6. Gently pry apart the deck from the hull, holding them apart with wedges. Straight blade screwdrivers work well as wedges. I started with a putty knife, and once I had a thin gap, used a cat's paw for more leverage. A 1/4" gap is wide enough.
7. Ream out the old sealer. A hacksaw blade works well. Clean with solvent.
8. Fill the gap with new sealer. I prefer polysulfide since it is more flexible than 5200, which is also difficult to remove later.
9. Remove the wedges.
10. Install the inserts and screws.
11. The best way to reinstall the old rub rail, because it needs to stretch around the tight curve to the transom, is to first attach the end of the rub rail at the transom with the end fitting. Then, using a crowbar, gently pry the rub rail in place, just like fitting a tire on a wheel.

[tac]

GLASSING THE HULL/DECK FLANGE

1. The assembled flange is covered with gel coat, and has sharp 90° corners. The rub rail covers the flange to a depth of about 1", and the mated flange is about 3/8" thick, so you'll need fiberglass tape of a maximum width of 2", or else some of the tape will show when the rub rail is reassembled. Because of the sharp corners (see para 4 below), and thinnish thickness, biaxial tape should be used. Otherwise you may have trouble getting the tape to conform around those tight curves (http://www.sollercomposites.com/NewSoller/Tapes.html).
2. Once the rub rail and inserts are removed, start by wiping down the hull and deck flanges with dewaxing solvent (https://shop.hamiltonmarine.com/prod...art-26130.html).
3. Sand the gel coat with 80 grit.
4. Round over each 90° edge to about a 1/4" radius. This helps the tape to conform to the curve.
5. Any good book on fiberglassing will give better details. There's Don Casey's book, Sailboat Hull & Deck Repair, https://www.amazon.com/Sailboat-Hull...ords=Don+casey, or, for free, download http://www.westsystem.com/the-gougeo...-construction/
6. If you need to hold the wetted tape in place until the epoxy cures, you can place the inserts over it. The insert plastic is slippy enough that epoxy won't stick well to it.
7. Once the first layer has kicked, fit a piece of the insert. If it looks like a second layer will fit, go to it.
8. When finished, fit the inserts, and redrill for the screws.

[azazzera]

That is excellent step by step instructions. Where were you when I did my thing. Unfortunately it sounded from his description that he may have a bit of core involvement. Complicates things a bit.

[rockhopper]

I'll get some pictures of the flange when I get back to my boat in an hour or two. I'm pretty sure I can see where the water is coming in, from inside the boat you can see day light.

[rockhopper]

Here are some pictures of the flange, you can see the wood between the flange and there is no lip that the plastic channel used to screw to in a spot or two.

Yeah I'll be using bumpers, rumor was that a hurricane had damaged the rail.

[tac]

Hull Flange Repair

The damage doesn't look too bad. It looks like the deck flange is still intact, but the hull flange is gone, while leaving the curve still in place. There's no core involved. A general procedure might be to use the deck flange as a mold against which to make a new hull flange. See a good reference for details. Experienced forum members, like Neil Dutton, may have better ideas.

1. Clean and dewax the area thoroughly
2. Use a grinder to bevel the underside of the hull flange broken edges to a slope of 10-15°. Call the bevel-to-bevel length of this the 'dressed length'. This provides a surface for new fiberglass/epoxy to bond to, similar to a plain scarf joint in wood. You may have to separate the deck/hull a bit to best do this.
3. Carefully wax the underside of the deck flange, making sure no wax gets on the newly dressed hull area.
4. If you separated the deck/hull flanges in step 2, reclose it
5. Cut strips of fiberglass cloth to cover the dressed area, about 1-1/2" wide by the dressed length. Do not use mat!
6. Since this is upside down work, cut a piece of wood about 1-1/2" wide by several inches longer than the dressed length. Round over one long edge to about a 1/4" radius. Sandpaper works fine.
7. Using fiberglass cloth and epoxy, start laying in strips, letting each strip get tacky before laying the next strip. Each successive strip should be slightly smaller to match the bevel angle
8. To hold the strips in place while each layer sets, wax the board, or wrap it in release cloth, and lay it over the bottom of the hull flange, rounded edge first, and clamp it in place to the deck flange.
9. After the repair has reached a satisfactory thickness (OEM was about 3/8" for the mated hull + deck flange), leave it till the epoxy kicks and finishes curing.
10. Remove the board.
11. Use a grinder to dress the repair to a final shape, feathering in the curve to the hull. It doesn't have to be pretty, the insert and rub rail will cover it. USE A MASK WHILE GRINDING! Green epoxy is nasty.
12. Any exposed epoxy should be covered with paint or gelcoat - epoxy deteriorates in UV (sunlight).

[rockhopper]

In the first picture you can see the hull flange broken, in the second picture if you can see it the deck flange is pretty much gone in spots. There is very little of it left, I can try to get some more pictures of it once this storm moves out

[tac]

Deck Flange Repair

This adds only a small complication. The process for reconstituting the hull flange remains the same. Start by first rebuilding the deck flange in a similar way:
1. Separate the deck and hull flanges.
2. On the outside of the boat, dewax and bevel the area of the damaged sides and top of the deck flange.
3. Clamp a thin piece of waxed metal, or stiff plastic like polyethylene, about 1-1/2" wide, under the damaged area of the deck flange. This will be the backer to ensure the underside of the new deck flange is flat.
4. Rebuild the deck flange with layers of fiberglass and epoxy. If needed, use a board of suitable length about 1-1/2" wide as a backer to press and mold the glass layers into shape as the top of the deck flange. If needed, roundover the inboard edge.
5. When cured, remove the top and bottom backers, and grind to shape.
6. Proceed to rebuild the hull flange.

[rockhopper]

Tac, when you say separate the hull and deck flange, you mean in just the section that needs to be repaired? What do I do with the wooden piece in between the hull and deck? Also is it possible to press the hull back in, because it appears the hull has moved out about a half inch or so. Thanks again for all of the helpful information. Can this repair be done on the water as I'd like to sail it some this season?

[tac]

1. Yes, you shouldn't need to separate any more than a couple of feet either side of the length to be repaired.

2. Get rid of the wooden piece - what use will it serve?

3. I looked at your first photo carefully, and can't see any sign of the hull bulging outward. Over a short distance like that (6 ft or so), fiberglass is too rigid to bow out a half inch. I think you're distracted by the missing sections of flange. Here are some measurements I took 15-20 years ago. Measure your flanges for comparison. When I get home Friday I'll gen up a sketch for you of the hull/deck join.
a. On the top of the deck flange there is a "bump", meant to be a sort of toe rail. From the outboard edge of the deck flange to the outboard edge of the toe rail is 1-1/16" (or so)
b. On the underside of the hull flange, the distance from the hull to the outboard edge of the hull flange is 1-1/8" (or so).
c. If you cut two pieces of wood 1-1/16" and 1-1/8" (or use two tapes) and hold one up to the outside of the toe rail and the other to the hull, their outside edges should align ('nuther "or so").
d. If they match up, there's no hull deformation.

4. Yes, the repair can be done in the water, either from the dock (easiest) or from a dinghy. Just keep it dry until the epoxy cures. Having power available will help.

5. Another (maybe the bestest) choice is to glass this whole hull/deck join section together as a single repair, rather than repairing the deck and then repairing the hull flange and then joining them with a sealing compound. When done it will not be easy to remove the deck from the hull, but I doubt on large boats that is ever done in more cases than about 1 in 100,000. If you want to do that it will save you about half the time. Description follows.