Hooked bottom

[richnle]

The 19 ft Grady I am working on has a moderate gradually curved hook that peaks at about 3/8" about 2.5 feet in front of the transom. How important is it to have water in the hull during the time that force is applied to gradually work the hook out? Could keeping water in the hull for weeks or even months cause rot and other damage to the garboards, rib ends, keelson and stringers? Does Anyone have a success story and advice on working a hook similar to this description out? Thanks!

[Robert]

don't soak the wood! this will just cause rot, as you figured.
you could try steaming, but i don't think that you can get the ribs soft enough. i assume they are oak?

i have a similar situation. the bottom is hogged (hooked) but all of the wood is in very good condition, so i don't want to take the bottom apart. i am considering 2 options:
1, with the boat upside down, running a strong batten along the the outside and use bolts and pads on the inside to slowly, over time, draw the bottom as close to fair as will reasonably happen.

2, fair the bottom with fairing compound. then cover the bottom panels with 1/4 ply sheathing epoxed and screwed.

i am currently drawn to option 2, as option 1 would most likely require option 2 any ways to get the bottom fair. just less compound.

i plan to do the 1/4 sheathing in either case. i know this will increase weight and change the bottom by filling the first lap. but it will also strengthen the bottom. and if it overly affects the ride, i will add bilge keel strips.

actually, in thinking it through today, i am now thinking about removing the bottom panels, fairing the warped ribs and replacing new bottom panels.
i will have to see what i find when i get there.
i also plan to reinforce the bottom structure with bulkhead floors of ply wood.

[thegammas]

I have the same hook issue. It very much affects the handling of the boat.

My approach is similar to your option 2. Going to epoxy thin strips (say, 1/8th inch) of white oak into the hooked area so as not to have so much filler. Get it close that way, then screws into the frames (just a few for that mechanical fastening that will make me feel better. Likely not needed.)

Then fill the voids in and around the strips with Smith's filler and sand it all fair. Coat just the garboard panels with Smith's CPES. Then of course, paint!

[JoeCB]

The problem of the "hooked" bottom is all too common on our old wood boats. Expanding on Robert's plan #1 idea, I have wondered if the following would work.... Three strong timbers (6X6's) as strong backs under the hull (hull in the upright position) extending from aft of the transom to well forward and in line with the three structural longitudinal hull members, keel and the two stringers. With holes drilled thru the bottom planks, adjacent to the members, long clamp bolts (threaded rod) with plates drawing the hull members down. The strong back timbers would have to be spaced out from true plane position to allow for some over compensation to compensate for likely spring back. All the load being applied to the three structural hull members, no direct load on the plank, ribs or the plank to transom joint.
Perhaps a little TEMPORARY moisture inside the bilge and weight could help move things along. All done , only a few small holes in the garboard planks to be plugged.
What do you think ? might work ...

Joe B

[thegammas]

Wow. I like it Joe. When I get to that stage I'm going to have to pull out the "thinking stool" (a famous Andreas quote) and decide which way to go

[richnle]

Thank you for all the input. I'll throw out and an idea I'm considering to try and pull the hog down. After removing the outer keel and blocking the hull upright, including blocks on the keel line at the transom and just forward of the hog, I am considering anchoring a fixture to the concrete floor with a turnbuckle and threaded rod running up through the inner keelson. I would make a fixture to span the keelson and stringers to either side which the threaded rod would pass through. Over the winter, I would periodically adjust the turnbuckle to gradually encourage the wood to straighten out by pulling downward. The ribs are white oak, and appear to still be strong. Any comments on whether this could make an improvement? Thanks again.

[Robert]

i don't think that you would get the stringers and keelson to bend permanently back to original shape. too large dimensionally. maybe the ply and the ribs. maybe with a lot of steam. but i think that this would just weaken the old wood.

i have been thinking on this a lot for at least a year! i'm thinking that trying to get the ribs and ply to bend again would just weaken the fibers and not be strong long term. with or with out steam.
i am actually going back to the idea of scabbing wood into the divots with epoxy, as described by thegammas then adding reinforcing on the inside.
basically fixing it in the position it is in. fairing the bottom and strengthening the structure so there wont be anymore (i hope) distorting.

[W Guy]

Well, it took a long time for the hog to form from letting the boat sit on something that pushed it up due to the weight of the boat itself, so why not try reversing the process? Maybe setting a large weight on the inside of the boat (like an engine block) would perform the same thing in reverse? It would take time though.

Verne

[JoeCB]

Just a word of caution, I would strongly advise against simply adding weight to the inside of the hull. I expect that that will only succeed in destroying the joinery at the transom. Any force applied downward must be counteracted with an equal and opposite force acting (up) against the transom joint.

Joe B

[W Guy]

I understand that consideration. My suggestion would to be to support all the areas under the hull that are not hogged and only apply the inside weight over the hog.
Verne

[Bellbuoys]

I have been out looking at 16' and 17' Thompsons and Lyman's from the 1950's and am amazed how many have a pronounced hook in the bottom. One seller suggested I need only soak the boat and add weight for some period for this to correct itself. Certainly not, and the issue of mold and rot was already identified in this thread. In thinking about what I have seen, why not unfasten the bottom planks from the ribs, and/or the ribs from the keel in the affected portion of the bottom, and insert shims of the appropriate wood type (white oak?) and length, then reattaching everything? I, for one, don't believe a keel can be easily straightened, despite the imaginative approaches raised earlier in this thread (impressive imaginations, actually), and the idea of adding layers of epoxy has its own issues. Surely, I cannot be the first to think of shims - what's wrong with the idea?

[richnle]

I like the last idea. Sounds practical enough to make an array of measurements from straight at each fastener location and make custom shims based on each measurement. With the ribs being white oak, it seems logical to me to make the shims from white oak as well. I would need to shim between the inner keel and the bottom planks as well. If I decide to give this approach a try, I'll report back over the winter on how it works. Let me know if we are missing anything regarding this approach. Thanks!

[Robert]

I think that it is all relative to the given situation.
if one simply has warping to the bottom panels and ribs, and you can soak and press them back to shape, fine. though i think that over time, ie several soakings, this will cause damage, and or the wood will just become overly flexible.
on the other hand, if like me your situation is such that the whole structure, panels, ribs, stringers and keel are all hogged, then soaking won't be effective. for me, one of the stringers was even being pushed up off of the transom.
i also don't like the idea of shimming between the ribs and bottom because this will alter the structural relationship. the strength comes from ribs sitting firm and being fastened tight to the panels and planks. in addition, all the years of these parts being tight to each other, and then separating them doesn't seem like a good idea to me. i feel that correcting the hog in place is more structurally sound. that is filling and fairing the bottom. in addition, this will add strength to these areas. unless of course what is needed is more rebuilding of the bottom.
and if the depth of the hog is 1/4 inch or more, i would shape a piece of plywood to fit into the hollow, and then fair it to the bottom.

[HalcyonDays]

The correct fix would be to replace ribs, garboards, keelson, and keel. Short of doing this will be a compromise. Another compromise would be to add trim tabs, I have seen a lot on older wooden boats. .

[Portside]

Interesting and creative solutions to a nasty and tricky problem. If I were approaching this problem, I would reject the notion of moisture and pressure to reverse what has likely taken 30-50 years to create. The wood fibers have assumed a new and quite permanent direction creating the "hog". While you might be able to temporarily get all members to assume a straightened bottom, I would submit that the solution would be relatively short lived before the members return to their deformed shape.
I believe the oak shim suggestion from Brad on all ribs, keel and sisters are the best solution. As you acknowledged Rich, this plan has some merit. I think your time and efforts will be well utilized if you can identify the specific deformed members and insert tapered, fitted shims glued and fastened in place. I would error on being slightly more in thickness than less.
Best wishes