Now on to skinning this thing.
This has been a subject of much thought. There is not an infinite amount of information around the web or books
that I've seen that really go in to too much detail about it, other than some ardent "dont's". I have the book "Steel
boatbuilding" by Thomas Colvin. There is a lot of good info there if one is planning on building a huge steel boat,
I'm not. And many of the methodologies explained therein really don't seem to apply to a hull this size. My main
concern is weight and strength. Half inch hull plating, and 1/2" bracing is out of course. From what I've read, we
only need to attach the skin at it's edges. It does not get welded to the ribs anywhere. Some of the best info came
from Weston Farmers' "From the old boat shop". I took away a few basic guidelines, don't weld to the ribs, only to
the keel, chines and gunwale. A flat plate of steel when it is bent in one arc and then twisted it creates a belly or
radius in the plate. Apparently some of the old shipwrights knew how to manipulate this when laying out a hull, and
could make the flat plate look like it was actually a three dimensionally formed piece. Making the hull perfectly fair
gunwale to keel. Sort of a lost art. I don't have that much time :) I'm at, whatever happens on it's own, happens,
and I'll deal with it at that point. I'll just follow the rules and hope for the best.
The stringers are left loose during the skinning, Once the outside of the hull is welded up and fair, the hull is
flipped, of course and then the stringers are pushed out of the slots tight against the skin and alternate stitch
welded their full length. THEN, the stringers are welded up in the ribs in the slots. This closes the slot and
restores the full strength to the rib once again. It also allows bilge drainage as the skin is standing off the ribs.
I was going to use 14 ga which is .075" thick on the whole hull. I've reconsidered. The plan is to trailer this, so at
least on the bottom, I'll use 12 gauge which is .105". Loading a boat this heavy on and off of a trailer with a bottom
that is not as strong as it should be is just inviting problems. In a perfect world, we would make the trailer fit the
hull perfectly and float it on to the correct position and drive away. Unfortunately, it doesn't often work out that
way. Many ramps are washed out from erosion, often times the wind is blowing from one side, strong current from
one side etc. Making loading up a trailer a real ballet. So we better go a little heavier just in case. It only adds a
hundred pounds. And too, I need to weld up a cluster of thru hull bosses for water pick ups and blow downs, I may
even have an optional underwater exhaust, in case I have a bunch of passengers and they don't feel like being
speckled on the after deck :)
For the patterns we are going to use tempered hardboard. The luan plywood just goes crazy unless it's nailed
down. The hardboard doesn't seem to be affected by humidity etc. And it's cheaper, about half the cost.
So here we are testing the first pattern:
This has been a subject of much thought. There is not an infinite amount of information around the web or books
that I've seen that really go in to too much detail about it, other than some ardent "dont's". I have the book "Steel
boatbuilding" by Thomas Colvin. There is a lot of good info there if one is planning on building a huge steel boat,
I'm not. And many of the methodologies explained therein really don't seem to apply to a hull this size. My main
concern is weight and strength. Half inch hull plating, and 1/2" bracing is out of course. From what I've read, we
only need to attach the skin at it's edges. It does not get welded to the ribs anywhere. Some of the best info came
from Weston Farmers' "From the old boat shop". I took away a few basic guidelines, don't weld to the ribs, only to
the keel, chines and gunwale. A flat plate of steel when it is bent in one arc and then twisted it creates a belly or
radius in the plate. Apparently some of the old shipwrights knew how to manipulate this when laying out a hull, and
could make the flat plate look like it was actually a three dimensionally formed piece. Making the hull perfectly fair
gunwale to keel. Sort of a lost art. I don't have that much time :) I'm at, whatever happens on it's own, happens,
and I'll deal with it at that point. I'll just follow the rules and hope for the best.
The stringers are left loose during the skinning, Once the outside of the hull is welded up and fair, the hull is
flipped, of course and then the stringers are pushed out of the slots tight against the skin and alternate stitch
welded their full length. THEN, the stringers are welded up in the ribs in the slots. This closes the slot and
restores the full strength to the rib once again. It also allows bilge drainage as the skin is standing off the ribs.
I was going to use 14 ga which is .075" thick on the whole hull. I've reconsidered. The plan is to trailer this, so at
least on the bottom, I'll use 12 gauge which is .105". Loading a boat this heavy on and off of a trailer with a bottom
that is not as strong as it should be is just inviting problems. In a perfect world, we would make the trailer fit the
hull perfectly and float it on to the correct position and drive away. Unfortunately, it doesn't often work out that
way. Many ramps are washed out from erosion, often times the wind is blowing from one side, strong current from
one side etc. Making loading up a trailer a real ballet. So we better go a little heavier just in case. It only adds a
hundred pounds. And too, I need to weld up a cluster of thru hull bosses for water pick ups and blow downs, I may
even have an optional underwater exhaust, in case I have a bunch of passengers and they don't feel like being
speckled on the after deck :)
For the patterns we are going to use tempered hardboard. The luan plywood just goes crazy unless it's nailed
down. The hardboard doesn't seem to be affected by humidity etc. And it's cheaper, about half the cost.
So here we are testing the first pattern:
My Steamboat Project Link to steamboat show
The Steam tug "Salty" built from Reliable Steams' plans Page 11
The Steam tug "Salty" built from Reliable Steams' plans Page 11
Seems to lay pretty flat.
The first step of this going to be the building of a long skinny table to handle these large sheets on. It will serve a
number of purposes. One is to lay the patterns on and cut, they are going to be 23 feet long and oddly shaped. I'm
no fan of working on the floor. I just do better work if I'm more comfortable. Another purpose is to lay the sheet
steel on and cut out, we are going to do each panel in one full sheet, to keep the hull fair. Another purpose is to
be able to move it around with the forklift, so we'll add forktubes, this will help us lift the whole panel near where it
goes and simply slide it off. Another purpose (yes I'm getting my money's worth out of it), is to use it as a long
scaffold, it will have short legs on it, so we can run it along side when welding the exterior and painting.
So on to that little build. We'll construct it to where it will store under the gunwale presently. We'll also turn the
angle flanges up so we can use it to burn the plasma upon. Unlike an acetylene torch where one piece of steel can
be cut out atop another and the one below is not damaged, plasma does not work that way. Any metal the plasma
blaze can find that shares a common ground will be cut as well, as deep as the plasma is capable. I found that out
the hard way..
Here are a few pics of this being built.
The first step of this going to be the building of a long skinny table to handle these large sheets on. It will serve a
number of purposes. One is to lay the patterns on and cut, they are going to be 23 feet long and oddly shaped. I'm
no fan of working on the floor. I just do better work if I'm more comfortable. Another purpose is to lay the sheet
steel on and cut out, we are going to do each panel in one full sheet, to keep the hull fair. Another purpose is to
be able to move it around with the forklift, so we'll add forktubes, this will help us lift the whole panel near where it
goes and simply slide it off. Another purpose (yes I'm getting my money's worth out of it), is to use it as a long
scaffold, it will have short legs on it, so we can run it along side when welding the exterior and painting.
So on to that little build. We'll construct it to where it will store under the gunwale presently. We'll also turn the
angle flanges up so we can use it to burn the plasma upon. Unlike an acetylene torch where one piece of steel can
be cut out atop another and the one below is not damaged, plasma does not work that way. Any metal the plasma
blaze can find that shares a common ground will be cut as well, as deep as the plasma is capable. I found that out
the hard way..
Here are a few pics of this being built.
Here it is doing it's thing:
After sliding it off, used ratchet straps to hold it up to the keel. I roughly trimmed off the excess to make it easier
to handle. As can be seen we have to fit it up to the keel:
to handle. As can be seen we have to fit it up to the keel:
To fit it up and transfer the contour of the keel, I made up this little tool. An impromptu margin scribe. I took the
largest dimension of the gap in between the tip and the hole where the Sharpie will go, and made the scribe for
this distance, it was 5.1"
largest dimension of the gap in between the tip and the hole where the Sharpie will go, and made the scribe for
this distance, it was 5.1"
Just kept it at a right angle to the keel and laying flat on the pattern which was down flush with the ribs. Inserted a
Sharpie in the hole, and drew the contour. Right on down past the shaft log and rudder tube. We only did this from
the tail stem to the base of the front stem. Beyond the base of the front stem, too much going on there, it will have
to be fitted, by guess and by golly.
Sharpie in the hole, and drew the contour. Right on down past the shaft log and rudder tube. We only did this from
the tail stem to the base of the front stem. Beyond the base of the front stem, too much going on there, it will have
to be fitted, by guess and by golly.
Then slid the pattern off back on the table/scaffold and let it down where we can cut it.
And cut it out with the Dewalt saber saw. Now it's ready to go back up and be laid out to the first chine.
Here we see it is fitting the keel well, around the shaft log and rudder. (why the margin scriber had a sharp point,
to get in around everything). Went right up first shot and fit perfectly. (Thankfully)
to get in around everything). Went right up first shot and fit perfectly. (Thankfully)
This is how I fitted the pattern around the base of the stem ahead of station 2. Just trim and check and try to mark it
out as close as possible. This aircraft saw came in pretty handy. It has it's place, and the majority of the time that
place is, in the toolbox, 3rd drawer up:) It's hard as heck to cut a straight line with, and it reciprocates too fast for
sheet metal, just burns the blades up, but it worked pretty well for this. It's definitely not one of my "go to" tools. It's
a last resort when cutting is needed in a tight spot.
out as close as possible. This aircraft saw came in pretty handy. It has it's place, and the majority of the time that
place is, in the toolbox, 3rd drawer up:) It's hard as heck to cut a straight line with, and it reciprocates too fast for
sheet metal, just burns the blades up, but it worked pretty well for this. It's definitely not one of my "go to" tools. It's
a last resort when cutting is needed in a tight spot.
Here we have it fitting the base of the stem. I have one little gap that I'll fix in it. Will need a smooth edge to guide
the plasma torch.
the plasma torch.
So I traced the chine on the other side, removed it back down and cut it out and replaced. It went right up and fit
well. The edge needs to be cleaned up and trued with a long sanding block.
well. The edge needs to be cleaned up and trued with a long sanding block.
Now on to the next pattern. Again, just laying the material up and getting some rough markings..
And the rest just went the same. Lay the pattern stock over, making sure it is contacting everywhere, mark it out and
cut it.
Skinning is covered on the next page 12
cut it.
Skinning is covered on the next page 12
