Wooden Boat People
By McKenzieDriftBoat.com
bottom removal question
I am working on a Don Hill that has been sitting in a chicken house for 5 yrs or so. It is in fair shape. However, the inside chine is rotten in some places and the side panel at midway is showing some rot which will need to be patched. Before I patch those areas the inside chine will need to be removed (which has been) and then the bottom, correct? The bottom has a crack (visible from inside) which probably caused a the leak which was retained by the inside chine and caused rot over time. My question is how to remove the bottom once chine log is removed.
There is no outside chine, just the fiber glass mat which stops just under the rub rail. I am going to replace the bottom so preserving it is not of concern at this point. Although, I would prefer an expert opinion in order to maintain the integrity of the areas which could be damaged accidentally. So how should I go about this?
I hope this is enough info to get a solid answer. Pics to come if needed. Thanks
Views: 496
Replies to This Discussion
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Permalink Reply by Randy Dersham on
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This method has worked well for Sanderson and me.
Drill a hole in the bottom in between each frame. Do the rest of the cutting with a flush cut bit on a router. Use a bit that has the flush cut bearing on the end of the bit to prevent burn on the frames. Insert the flush cut bit into the drilled hole then cut the bottom flush to the frame and the side panel. Usually this runs along the chine log on the inside of the boat. If there is no chine log then be careful to not cut the side panel.
Do this between each frame. This will leave you with small strips of bottom that is still attached to the frames and the chine log. Carefully use a chisel to separate the plywood. The goal is to leave the last layer of plywood glued to the frame.
Then we use a 4x24 belt sander with 40 grit to cut that last layer of plywood and remove the glue. It will take a few belts if the bottom was put on with 5200. 5200 gums up belts pretty fast.
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Permalink Reply by Chase Pritchett on
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Sounds progressive and very well explained. I suspect this needs to be done from the bottom.
So I need to let the bearing ride against the frame and then remove the remaining plywood. I'm thinking that I should take care to not sand too much on the frame in order to make some purchase when attaching the new bottom.
I've already removed the chine logs so would it be better to do the side panel sections by hand just to be careful not to damage it?
Can you reccommend a hand router that would be better suited for this type of cut and future use on the boat when needed?
Thanks
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Permalink Reply by Don Hanson on
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Porter Cable T-2 is my favorite all around router. Lots of accessories are made to fit this particular popular router. I have a 'socket' in the top of my workbench for mine. I cut a hole to fit the router base so it fits flush with the table surface. Did the fine fitting by bedding the router in Bondo or Epoxy putty so it fits in there very snugly.
You can then just drop the router into the table and do lots of operations. To change a bit, you just lift the router out, or to cut something on the boat or some other project, again, the router just lifts out without any tools or screws to dissmount.
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Permalink Reply by Dave Z on
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Randy, I'm gonna store that method in my memory bank. I like it. Hopefully I don't need to use it!
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Randy, I tried this method and it seemed to work. However it was very slow and I had to stop frequently to let the bit cool. The frame sections are floating so I didn't need to worry about damaging them as previously planned. The frame makes a curve upward abour 2.5" from the chine log and keeps a good 1" off the bottom to the next curve. (not sure what this method of cut is refered to as) But I will definitely use the router for cutting around the frame joints.
Also, as I made my initial cut I noticed the bottom to be solid fiberglass (guessing 5/8").
1) Is a solid FG bottom uncommon for thesde boats?
2) Is there another method better suited to cut solid FG? (3" circular saw perhaps?)
Don, the Porter Cable Idea is a 'goodie'. picked one up today and will find to be useful I'm sure. Thanks for the advice.
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Hmmm, I don't understand. Are you working on a fiberglass Don Hill boat? Are the sides fiberglass? Photos would help if you can post some.
Yes, you can use a circular saw but you have to be very careful to not over cut. Then finish your cut with a hand saw. We have done this but it is more nerve wracking than using the flush cut bit.
We use a 3 1/2 HP Porter Cable with a 1/2 flush cut bit. You want the router bit to blow chips not fine sawdust. If it is blowing sawdust instead of chips then slow down the router speed. This can help with overheating and the bit will ware a little longer. We've never had trouble on a wood boat bottom. I haven't cut off a solid fiberglass bottom. Would a different bit do a better job. That's new for me, so I don't know.
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It's definitely a 3/4 " FG bottom. And the sides are wooden. Best I can tell is the previous owner replaced the bottom with FG and did a crummy job at that. (hence the leaks that destroyed the chine log and part of the left side at midship. Yet the area of floor and chines around the transom is in good shape)
I'm using the same router setup you mentioned but it is throwing dust. It made a good cut for about a ft and 1/2 then got sluggish. I'll slow it down and see if that makes a difference. I'll give it a whirl with the C saw stnding from sides of the boat and let it drop out in sections. But I will make sure to use the router for the areas around the frame and close to the sides. Probably leave 3" to work with. (does this sound okay?)
Randy, I will post some pics tonight if I can. I am working out of my dad's shop which is a hop, skip, and a jump from my house.
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A 3/4" fiberglass bottom....that is not likely or that bottom is massively overbuilt. We cut into the bottom of a 60' Krogen trawler yacht from Taiwan and it's bottom was not that thick. Making the full cut with a router on a glass lay-up that thick? That will certainly be difficult and dull up any router bit. You may want to cut another way, close to where your finished cut wants to be and then clean it up with the router.. Did you perhaps mean 3/4" plywood with fiberglass over that?
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I did't see any when I made the cut (shavings were solid white, no wood dust) and it's almost transparent in some places from rock wear (which both led me to thinking it is solid FG). That was my first question to a friend of mine who built his own and he looked at me as if lobsters were crawling outta my ears. So I gather, solid FG bottoms are uncommon?
Here's some pictures I took when I first picked it up for now. I'll take some more and post this evening. Hope these draw a somewhat clear picture for now though.
Again, thanks for all the replies and opinions. you guys have been truly helpful. Later
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Very interesting. Well you have a unique boat.
It sounds like the bottom is going to dull a router bit too quickly to do the job for you. A circular saw will work, you just don't have any protection where you can't see the blade. Be careful and us the same method of cutting out the sections between the frames and then use a big chisel to pull the bottom off of the frames.
Best of luck
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The circlular saw works great for the larger areas (with diamond blade).
Slow work with the router around the sides and frames.
All in all not too shabby a job. Just nerve racking and drawn out.Thanks for all the advice. I will keep posting progress on my page and ask questions for some of you guys.
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