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 18 hours ago by Dr PR

[Dr PR]

So how am I supposed to create this sheathing with the scale 0.005 inch (0.13 mm) gaps between the planks? I quickly abandoned the idea of using 0.005 inch thick brass shims to space the planks. Instead I decided to bevel the edges of the planks and jam them together, leaving a visible gap at the top surface.

 

A couple of years ago I was looking through build logs on the forum and was envious of some of the models that had elaborate moldings instead of plain rectangular trim. I knew that this effect was achieved with draw plates with a variety of cutouts, so I bought four Artesania Latina draw plates for future use. Well, the future is here, and I used the 1x4 mm cutout to round the edges of the 3.9 mm wide sheathing planks.

 

 

This worked petty good. The "corduroy" effect is very subtle, but with the proper lighting angle it is noticeable. I have finished the port bow and the port aft sections above the water line. The very thin basswood planks bend and twist to shape without the need to use heat, and the glue is good enough to hold them in place without clamps. But I did use blue masking tape to hold the planks in place until the glue (Sig-Bond Cement) set. 

 

 

I need to be sure to remove excess cement between the planks after they are positioned. It fills in the gaps and is hard to remove after it has hardened. I use the tip of an old #11 blade drawn backward (top or flat edge first) through the gap to scrape out any glue that flows there.

 

Austin Cox (the current Cape owner) has confirmed that the sheathing planks that remain at the bow of the ship today were not tapered. They are the original 7 1/4 inch wide planks, and he has replaced at least one of the original parts. So I will complete the sheathing planking below the water line without tapering the planks. Fitting and trimming the pieces to the bilge keels, garboard strakes and keel should be interesting! It definitely will be contrary to the traditional modelling dogma of tapering the planks precisely to meet that preconceived "ideal."

Edited 12 hours ago by Dr PR

[Dr PR]

I suspect I have given the impression that everything we did on the Cape was a failure. Much of it was, because the ship was poorly designed for the things it was asked to do.

 

We did have several successful training sessions for everything from streaming mine sweep gear to shipboard firefighting. And for me it was something of an extension of Officer Candidate School where I got some valuable ship handling experience.

 

But one of the more unusual missions called for the Cape to carry Marine commandos close to shore the night before a training assault landing at the Marine Corps Base at Camp Pendleton north of San Diego, California.

 

We rendezvoused with a LST (Landing Ship Tank) in the late afternoon and took aboard the Marines and their boats and gear. Notice how much larger the LST was compared to the Cape (on the right in the photo) – and LSTs weren't considered large ships, only about 300 feet long, or three times as long as the MSIs and 13.5 times a MSI's displacement.

 

That night we proceeded in close to shore where the commandos launched their boats and disappeared into the darkness. Then we motored back out to sea to wait for the morning's assault to begin. Mission accomplished!

 

I guess the MSIs were perfect for this type operation. They were shallow draft and could pass for a fishing boat at night. And if the enemy did spot them and open fire the ships certainly were expendable.

 

We didn't have to wait long before several ships began shore bombardment at first light. It was my first exposure to (relatively) large caliber gun fire. A destroyer was about half a mile from us, and when it fired the 5"/38 guns we saw the flash, followed a few seconds later by the BOOM! The sound hit me like a punch in the gut. That was a surprise!

 

It was just an introduction to Naval Gunfire Support (NGFS). When I was on the Oklahoma City in Vietnam we conducted NGFS for six to eight weeks at a time. I lost my high frequency hearing while standing watch for hours with the 5"/38s and 6"/47s firing only a few yards away. When I see films of Marines landing on Pacific islands in WWII with battleships blasting away nearby I wonder if those guys were totally deaf by the time they hit the beaches?

 

We were ordered to patrol the boundary of the assault area to keep civilian craft out of the restricted zone. We motored back and forth along the south end of the landing area for the rest of the day with few boats coming near. But after a while a huge yacht came up over the horizon headed north at about five knots. It was almost as big as the Cape, and possibly even larger.

 

We had signal flags flying to warn vessels to stay away, but only naval craft would understand the code. As the yacht came closer we used the 12 inch signal lights to catch their attention, but it kept on heading directly into the invasion force. When it was a few hundred yards away we started sounding the ship's whistle, but we could see no one on the bridge. It was running on "iron mike" – a term for auto pilot. We pulled close alongside, sounding the horn and flashing the signal light. Finally someone appeared on deck from a cabin near the stern and raced toward the bridge.

 

We tried to communicate by radio but they weren't listening to the marine frequency. Our Captain shouted at them through a megaphone, but the person on the yacht's bridge didn't seem to understand.

 

Then, shouting as loud as he could to be heard over the Yacht's engines, he said "You are heading into a mine field!" There actually was a practice minefield in the landing area, and the big boy oceangoing minesweepers (MSOs) had started the invasion by sweeping the area.

 

That message finally came across, and with a roar of engines the yacht turned west. As the hull rose to planing the boat raced off into the sunset at two or three times the Cape's maximum speed.

 

Mission accomplished again! Twice in one day!! So the ship wasn't totally worthless.
 

Edited 12 hours ago by Dr PR

[Coyote_6]

I love these Cape stories Phil.   Really brings her to life.  Good deal.