USS Cape (MSI-2) by Dr PR - 1:48 - Inshore Minesweeper

[Dr PR]

I'm back!

 

I have been thinking about the third layer of sheathing on the MSI hull - and scratching my head to figure out how it was applied. I need some help here!

 

The blueprints say the sheathing was applied from the 11 foot waterline down to the bottom of the keel, bow to stern. Coincidentally, the top of the boot topping is also at the 11 foot waterline. To make things more interesting, the 7 1/4" x 3/4" red oak planks were attached with a 1/4 inch gap between them, and the blueprints are clear that this gap must not be filled with anything. Nothing is said about tapering the planks. So how were the sheathing planks applied to the hull?????

 

The current day Cape offers few clues. From the photos the owner Austin Cox sent it looks as if that outer layer of sheathing was removed at some time in the past. Only a small amount remains at the bow. Here are some photos he sent of the ship out of water.

 

 

The red lines show the lay of the outer layer of the hull planking. These planks appear to be tapered, and about 2/3 as wide at the stern as amidships.

 

The green lines show the lay of the remaining sheathing at the bow. You can still see the 1/4 inch gaps between planks, but they have been filled in a bit over the years.

 

It is obvious that the sheathing planks run parallel to the top of the boot topping, as the original blueprints show. But look at the bottom of the sheathing - the planks appear to intersect the garboard strake and keel at an angle, and do not run parallel to them.

 

So the question is whether or not the sheathing planks were tapered? From these photos it appears they were not, and were trimmed at the ends to fit where they met the garboard strake and keel. All opinions are welcome!

 

One other thing you can see in the photos, and is shown in the blueprints. The metal stem band rides over the sheathing. Great! Now I need to rip it off the model, apply the sheathing, and put it back again over the sheathing!

Edited Monday at 09:29 PM by Dr PR

[Coyote_6]

Curious construction Phil.  Based on the images of the remnant simply scribing them would render the effect, but who would want to scribe 40 something parallel lines onto the hull?  Am I right those "gaps" would be 0.005" at 1/48 scale?

 

Yikes.

Edited Monday at 09:31 PM by Coyote_6

[Jim Lad]

Phil, I appreciate your quest for absolute accuracy in the model, but at 1/10 of a millimeter at scale, would those gaps even be seen?

 

John

[Dr PR]

Steve,

 

The gaps will be 0.005" (0.127 mm)! I think I will just apply the planks pushed together carvel style and then run a scribe along the joint to create an apparent gap between the planks. I do have some 0.005 inch brass that I could use as shims, but I think that would just be asking for trouble.

 

For what it is worth, the basswood scale planks I have are about 0.154 x 0.0155 inch (3.9 x 0.04 mm). That comes out to 7.39 x 0.744 inches at 1:1 scale. The original red oak sheathing planks were 7.25 x 0.75 inch. The scale planks are a little wide, but almost perfect thickness. And no, I do not intend to try to shave 0.0029 inches from each plank to get perfect scale! I do not have the tools to do that.

 

Jim,

 

The gaps are very apparent in the photos I took of the Cape back in the 1960s, so they should be seen on the model, at least if you look closely. Those parts of the hull appeared to be "corduroy" planking.

Edited Monday at 09:49 PM by Dr PR

[vaddoc]

Very enjoyable journey Phil, just caught up with your build.

3/4 inch planks are very thin - what purpose did they serve?

 

Vaddoc

[Dr PR]

Vaddoc,

 

That is a very good question! The blueprints don't say anything about the function of these "sheathing" planks.

 

However, I can make an educated guess. The sheathing extends above the waterline in places where heavy objects (anchor, minesweeping floats, acoustic minesweeping device, etc.) are hoisted over the side. So it seems to be there for protection of the hull planking.

 

Minesweepers often operated in shallow waters (especially an "inshore minesweeper" or MSI) where they might run aground. The entire hull surface below the waterline is covered by the sheathing. I guess the sheathing below the waterline is there to protect the hull planking.

 

The sheathing itself provides no water tight integrity given that the planks were placed with 1/4 inch (5 mm) gaps between the planks. The blueprints specifically say that nothing is to be placed in the gap. But the sheathing was installed over a waterproofed cloth covering on the hull planking. That would provide some protection for the hull planks. Maybe the sheathing was there to hold the water tight cloth covering in place?

 

I know the larger ocean going minesweepers (MSO) had similar sheathing along the sides where heavy objects were handled - I have a photo showing this. So this seems to be a common feature of wooden minesweepers after WWII. But on the MSOs the sheathing planks were placed vertically - with gaps between them - instead of horizontally like the MSIs.

 

The MSIs were built in shipyards that specialized in wooden fishing boats. I wonder if they had the same type of sheathing? So far I have found no answer to that question.

 

****

 

Scale (1:48) planks are VERY thin - 0.015 inch (0.4 mm). They curve and twist to fit the hull curvature with little effort. Just the glue holds them in place without any clamps. But I have been taping them down with blue painter's masking tape to give the glue a chance to set.

Edited 3 hours ago by Dr PR