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 May 5 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 May 5 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 May 5 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 May 7 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 May 8 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 May 8 by Dr PR

[Coyote_6]

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

 

 

[Dr PR]

I have been working on the hull sheathing while finishing the topsail schooner build.

 

 

The rounded edges on the planks created by the draw plate do a good job making the gap between planks. The biggest problem so far has been glue (Sig-Bond Cement) squeezing up between the planks. If it hardens it hides the gaps, so I must wipe off as much as possible immediately after placing the plank. Then I drag a sharpened wooden toothpick point along the groove to gouge out any remaining glue. This also tends to spread the planks a bit, enhancing the gap. The planks are so thin (0.015 inch or 0.4 mm) that they conform to the curves of the hull without any special bending, and are held in place by the wet glue. Nevertheless, I use blue painter's masking tape to hold down the planks until the glue sets.

 

 

 

 

The planks at the stem will be covered by the brass stem band. First I will carve them to zero thickness at the "rabbet" where the hull planks meet the stem so the stem band will conform to the shape of the planking.

 

After the glue sets, if any of the planking gaps are obscured, I pull an old #11 knife blade with a broken tip along the gap, dull side first, to scrape out any dried glue. I can see painting the hull will be interesting because I don't want the paint to obscure the gaps!

[vaddoc]

I don't think you should worry about the paint filling the gaps Phil, if anything it should make these stand out more.

[FreekS]

8 hours ago, vaddoc said:

, if anything it should make these stand out more.

Especially if you use an airbrush!

[FriedClams]

Just catching up, Phil and you're doing some very nice work on this model.

 

On 5/5/2025 at 5:22 PM, Dr PR said:

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!

 

On 5/7/2025 at 6:45 PM, Dr PR said:

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.

 

I have never seen anyone install this type of sheathing on a boat before - except that this is exactly what I'm currently doing on my F/V Pelican.  How coincidental.

 

So, I can offer what I know as it pertains to mid-century wooden F/V in New England.

 

The sheathing was installed below the gallows frames and extended down well below the waterline.  The sheathing was ¾” oak and protected the hull from the heavy steel edged “doors” (otter boards) when the trawl gear was deployed and retrieved.  This sheathing is sacrificial and was replaced/repaired as needed.  They are not tapered and there are no gaps between boards.  The Roann (built in 1947) is a small eastern-rig dragger and part of the Mystic Seaport Museum collection.  In the image below, one can see that the starboard sheathing not only covers the hull below the gallows but also extends in a narrow band at the waterline forward to the stem.  On port side, there is only the narrow band which extends to midships because there are no port side gallows frames on this boat.  My understanding is that because this class of offshore F/V fished year-round, the forward waterline sheathing is there to protect the hull from floating slabs of ice in a time when harbor freeze-overs were not uncommon.

 

 

Here’s is the sheathing that I've applied to the Pelican as per the plans and images of other vessels by the same designer.  This is complete minus the trim to protect the end grain, and the waterline band still needs to be extended onto the stem.  Because this boat had four gallows and could drag off either side, I will be sheathing the port side identically. 

 

 

If not helpful, I hope this is at least interesting.

 

Gary

Edited May 17 by FriedClams
Spelling

[Dr PR]

Gary,

 

Thank you very much! This is not only interesting information about fishing boats, it does help me understand the origins of this practice. Interestingly, the Cape's planking was 3/4 inch red oak, even though the ship was built in Washington State where Douglas fir was abundant and cheap.

 

You mentioned trim to protect the end grain. A vertical angled strake behind the bow sheathing is shown on the MSI blueprints, and in the photos of the bow of the current Cape. The blueprints don't say anything about how the sheathing was applied between the bow and stern! My photos of the ship in the 1960s don't show this end grain protection for the sheathing farther back along the sides. But the pictures are pretty grainy and hard to interpret. Do you think it should have vertical pieces to protect the end grain?

 

Not tapering or spiling the planks really goes against the grain (pun intended) of everything I have learned about wooden hull construction. I am now carefully cutting the planks to sharp points where they fit around the bilge keels. And soon they will be tapering to fit the garboard strakes. And somehow the planks will have to flow off the after curved hull surfaces onto the flat deadwood and stern frame around the prop and rudder. The blueprints show them running parallel to the bottom of the keel on the deadwood at the stern.

 

I don't know how this will turn out!

 

****

 

I have been following and admiring your Pelican build. You are doing a beautiful job.

Edited May 15 by Dr PR

[Dr PR]

Here are a couple of photos to show the "lay" of the sheathing. On the real ship this sheathing was made of 3/4 inch thick red oak planks.

 

 

The blueprints say nothing about how to place the planks around the bilge keels - but they do say to cover the bilge keels with the sheathing. Tricky! But you can see how I am trimming the planks to fit up to the bilge keel.

 

The blueprints say to trim the sheathing around hull openings, rudder plates, seachests and the stern frame. I will have to relocate the sacrificial anode adjacent to the starboard sea chest.

 

 

Here you can see how the sheathing planks meet the garboard strakes at an angle, rather than being spiled to run along beside the garboard. The blueprints say to cover the garboard strake and the keel with sheathing, but to not cover the worm shoe (it is also made of red oak).

 

The thin red line shows where the brass stem band will fit over the sheathing. The sheathing planks will be tapered gradually to zero thickness where they meet the stem so the stem band will fit smoothly over them. It's "deja vu all over again."

[FriedClams]

 

On 5/15/2025 at 4:23 PM, Dr PR said:

My photos of the ship in the 1960s don't show this end grain protection for the sheathing farther back along the sides. But the pictures are pretty grainy and hard to interpret. Do you think it should have vertical pieces to protect the end grain?

 

Phil, on my boat I would say yes.  To keep the end grain from absorbing water and quickly rotting away they must have done something to impede that process.  Being a low-tech fishing boat of the 1940s, I have this image in my head of a guy slathering the board ends with pitch/tar and then pushing the vertical strip into the mess and nailing it down.  But that’s just a thought based on zero evidence of what they actually did.

 

But considering the USS Cape, wasn’t the military using epoxy decades before it was widely used commercially?  If so, I wonder what purpose these vertical boards would have served except for added mechanical protection against crushing/splintering the plank ends.

 

On 5/15/2025 at 4:23 PM, Dr PR said:

Not tapering or spiling the planks really goes against the grain (pun intended) of everything I have learned about wooden hull construction.

 

Yes, sometimes I feel like I'm building a bulbous shed.

 

Your sheathing is more extensive and complicated than mine and your plank widths are wider which further complicates the process, so I don’t envy your task.  But you’re making a great job of it and the added interest it gives to the hull will make the effort worthwhile.

 

Gary

 

 

[Dr PR]

Gary,

 

About the epoxy and the Navy. I don't know how far back that goes. But we did use epoxy paint in the missile house and warhead magazines because we couldn't paint in those spaces while ammunition was loaded. So it was a big project to offload everything at a Weapons Depot and repaint the magazines. However, the grey paint that was used topsides seemed to me to be water soluble and had to be repainted continuously. When I asked our Weapons Officer why epoxy paint wasn't used topsides he replied that there wouldn't anything for the crew to do to keep them busy. "Idle hands are the tools of the devil ..." So they chipped paint.

 

I don't like how this planking is turning out. I have finished the sheathing down to the bilge keel. The planks from the bow are at a sharp angle to the planks from the stern. I have no way to know how they should come together. It looks like a mess to me!

[Dr PR]

I have almost completed the sheathing on the starboard side. I am waiting to see if this works out before continuing on the port side.

 

 

CAUTION! This planking pattern is speculative. The blueprints say the entire hull below the boot topping had an extra planking of 3/4 inch red oak planks that were spaced 1/4 inch apart, with nothing in the gap between them. Other than that there are no instructions how this sheathing was to be installed. As noted above these planks were not tapered at the ends. So this is my best guess (and only a guess) as to how to apply these planks!

 

In the photo above you can see that when the planking parallel to the top of the boot topping is extended below the bilge keels it comes together at an angle. And there is planking parallel to the keel and garboard strake that also intersects the upper planking at an angle.

 

You can see in this photo the sheathing does angle downward at the bow, just like in the photos of the modern day Cape. The lower planking has a bit of an upward curve as it comes to the bow. It was apparent that something had to give, and some of the planks must be cut at an angle to join with the others.

 

But how? After thinking about this for a while I came up with the idea of joining them in a herringbone pattern, alternating between the upper an lower planking.

 

 

Here you can see the junctions between the planking (left) with red lines to outline the herringbone pattern (right).

 

 

 

If you look closely in the photos above you can also see I have planked the garboard strake and the keel with sheathing. But as instructed in the blueprints I didn't sheath the worm shoe at the bottom of the keel.

 

This section of a blueprint shows how the sheathing fit around the garboard strake and keel. The more or less horizontal planks were installed first, and the vertical side trim was applied next.  Cutting and fitting these pieces was tedious and tricky!

 

 

 

 

The real problem is shaping up at the stern along the skeg/deadwood and stern frame (propeller and rudder frame).

 

The blueprints show clearly that the sheathing planks on the skeg were parallel to the bottom of the keel. It was easy to fair the sheathing on the garboard strake into the sheathing above and below it, carrying the planks straight out to the stern frame. But as these planks come out onto the body of the hull they develop a significant curve (requiring wet heat for bending).

 

The planks laid parallel to the boot topping are bending inward toward the center line near the stern. But the curvature is not as great as the planking meeting the skeg. The gap at the narrowest point (arrows) is three planks wide, so the upper and lower planking will come together nicely, except for a triangular space that will require a filler/stealer.

 

The upper and lower planks come together at an angle, so they will have to be trimmed in a herringbone pattern like I have done at the bow. But it is a very narrow angle, requiring the planks to be cut to a sharp point. And as we all know, this is supposed to be a no-no! But I really don't know what else to do given the constraints on the sheathing planks.

 

Is this a perfect solution? How can it be when I don't even know what it was supposed to be!? Is it a good solution? Maybe, maybe not. But it does allow me to move on past this part of the build and get on with all the complex deck houses and minesweeping gear. I have already started on the CAD drawings!

Edited Sunday at 07:39 PM by Dr PR

[tmj]

18 minutes ago, Dr PR said:

CAUTION! This planking pattern is speculative. The blueprints say the entire hull below the boot topping had an extra planking of 3/4 inch red oak planks that were spaced 1/4 inch apart, with nothing in the gap between them. Other than that there are no instructions how this sheathing was to be installed.

Perhaps this 'clause' is 'someones' way of leaving the options for planking and caulking open, in the contract, without holding things up at the shipyard? 

[Dr PR]

tmj,

 

That is likely true. Shipyards/boatyards have their own "right way" to do things that doesn't have to be explained.

 

When researching the Cleveland class cruisers (27 built) I discovered I sometimes could tell from photos which of the four shipyards each ship was built in. Although they were all built from the same blueprints each yard had a "better idea" and created their own unique designs and builds, often significantly different from the Navy blueprints. Some of these changes were adopted by the Navy and sent out to all the yards as revisions. I suspect no two ships were built the same, not even when laid down side by side in the same yard.

 

Wooden ships, old and modern, were built the way the shipwrights thought they should be built. Since the MSIs were designed and constructed in yards that made fishing boats, I am sure a lot of the things the yards normally applied to fishing boats also went into the MSIs. So the blueprints left many things open for the boat builder to do as they had always done. And of course, everyone who built fishing boats knew how to apply the protective sheathing, so why bother to spell it out? However, the 300+ pages of MSI blueprints do specify a LOT of nit-picking details, like how long the threads on bolts should be, how different timbers should be joined, and how many coats of a specific type sealant should be applied.

 

I found this same approach to design and building applied to topsail schooners (Baltimore clippers) when I researched my schooner build. Every builder and shipyard had their own way of doing things. And there were no blueprints, just a specification saying "this is what I want." And it was up to the yards to build it.

Edited Sunday at 08:33 PM by Dr PR

[Dr PR]

The sheathing layer is finished!

 

 

The port side has three places where the sheathing extended above the boot topping. At the bow the sheathing protected the hull planking from the anchor. The stern sheathing protected from damage caused by lowering and raising one of the minesweeping "pigs" (floats). The sheathing just aft of midships protected from damage when handling the ship's boat and when deploying buoys.

 

 

The bottom sheathing protected from damage due to grounding. The odd herringbone pattern is not visible when the model is resting upright. It was an interesting exercise in parquetry.

 

 

The brass stem bands are back in place at the bow. Now I am back to where I was in January, before the fuss over the sheathing came up!

 

I used a two part 15 minute epoxy from Bob Smith Industries to glue the metal to wood. It was messy, sticky, and required some clean-up on the model and the tools (and my fingers) but epoxy is the best way to bond metal to wood (or metal, glass, and any non-porous surface).

 

This was some epoxy I bought at my local hobby store - back when it was still in business. I have had it for many years now and it is still good.

 

 

 

The planking at the stern faired very nicely onto the skeg/dead wood. I was concerned about covering the swelling around the propeller shaft, but the thin planks formed around it smoothly.

 

The sheathing on the garboard strake blended smoothly with the other planks. I think this outer layer of planking may even be better in this region than the original hull planking that was painstakingly carved, filed and sanded to get a smoothly curved hull!

 

The new sheathing has been filed, scraped and sanded to get a smooth surface. I will go over the gaps between the sheathing planks once more and then paint the new wood with a thin coating of sealer. Then I can get on with installing the deck house framing and the deck planks.

Edited 15 hours ago by Dr PR

[Coyote_6]

Well worth the effort Phil!  Very nice work and a very unique feature.  Nice.

[Dr PR]

Steve,

 

It was a learning experience! I was unaware that a sacrificial layer of sheathing was added to wooden boats to protect the hull planking.

 

I am really glad that Gary (FriedClams) posted the photos and information about the sacrificial sheathing on fishing boats!

Edited 15 hours ago by Dr PR

[vaddoc]

This was very interesting Phill (and very well done!). I also had never heard of sacrificial sheathing before.

Somehow though, I kind of think that, even though the expertise existed to properly spill and bend planks, it would be unlikely to spend time and effort in a military vessel, especially for a sacrificial layer that would not contribute to hull strength or water tightness. I think they just screwed the timber in, any way it seemed more time and material efficient, not far of what you ve done.

 

Vaddoc

[SaltyScot]

You really did make a grand job of that sheathing, Phil. The end result here looks quite elegant. I enjoyed reading your comments on what the different areas of sheathing are actually for, a nice insight into a "working boat" design.