LCM-3 Conversion to Navy Dive Boat

I am looking at a kit bash based on the LCM-3; simply because LCM-6’s are not available. I realize that I could convert the 3-boat into an LCM-6 mod 0, and still am considering that.

Anyway, I’m curious if anyone out there has assembled the Trumpeter or Revell of Germany 1/35 kits, or the Hobby Boss 1/48 kit, and what was your opinion of it as far as fit, ease of assembly, etc.

The plan is to only use the modified hull and aft deck, for the most part. The well will be covered by a cabin, and most of the detail parts will not be used.

Thoughts please.

Looka here! Is it another brown water navy build? I’m dreamin’ about doing that in 1/72 - but that’s all for now - only dreaming. I’ve got Trumpeter’s LCM-3 in 1/72 and the way I see it I would need another one, then saw them both in two and joining - that way I wouln’t have to build the “lengthening plug” by myself, just to save time when building.

Can’t relly help you in the scales you mentioned, but I sure would love to see you building that!

Good luck and have a nice day

Paweł

Pawel, to convert the 1/72 LCM-3 to a LCM-6 Mod 0, for a Program 4 Tango, Monitor, Etc., you only need to lengthen by 1 inch.

The project I’m looking at is a semi-modern (my period of service) U.S. Navy Dive Boat. We had them converted from both old LCM-3’s and LCM-6’s. Until the “Standard Navy Dive Boat” came out, (around 1988), Dive units just built their own in accordance with their needs. That’s my plan.

I’d prefer to start with the LCM-6 Mod 1 or 2, but they just aren’t available.

If you are splicing hulls, I’d be happy to offer tips. I love doing it and there’s usually a few things to consider.

Bill

i’ve cut model ships in half to both shorten & lengthen them. doing that in my Arizona OBB kitbash thread for the Wyoming, New York & Nevada classes.

I’m sticking with the 3-boat this first time around, but Pawel might be interested. Lengthening the 3-boat probably wouldn’t be too hard, but I would not be surprised to find that there are some tricks to getting it right, and square. I will keep the offer in mind.

In 1/72, it’s likely down to how the kit hull is constructed.

Juggling a cut plug (two seams) might be easier at the smaller scale. Depending oun how a cut plug cam out of the donor, naturally.

The cut wants to be just forward of the aft end of the well, with appreciation of just wher a person will be comfortable with putty and sanding.

In larger scales, I’m pretty sure I’d do it as a single cut on two kits. Strike a line on both kits about four scale feet from the aft well bulkhead on both. This line ought be adjust ed to presecerve deck & other moulded details. Cut the after portion three feet forward of the line; cut the donor three feet aft. Then join the two.

The remaining halves could be made up as one of the many iterations of dive/work boat, or ramped lighter, seen about the maritime world. Such craft have the helm position removed to be replaced with a cabin (or a shanty house) structure.

Toughest part is with modeling how crudely such craft are built, what with obvious weld seams, rickety wood cabins and the like.

I’ve ordered the Trumpeter, 1/35 3-boat and am going to build her out from that, based on the configurations of the dive boats I’ve worked on.

The Standard Navy Dive Boat was based on a 50’ workboat hull, whereas most previous ‘homebuilts’ started with an 56’ LCM-6 Mod 1 or 2. The Mod 3 (slab sided) had potentially lots of deck space for diving, but is a giant brick for maneuvering in a tight harbor.

While I was in, there were still a few converted LCM-3’s around; I know USS Jason’s dive boat was one, because I designed the air control console they used.

I built the Trumpeter 1/35 kit when it first came out in 2006 or so. The Trumpeter kit and the Italeri kit appeared at nearly the same time, so I remember reading a lot about both of them. IIRC, the Italeri kit was more costly, but the Trumpeter kit had a hull that was too deep. I picked the Trumpeter kit because I was converting it to RC, and the bit of extra depth was needed, as it allowed me to fit a NiMh AAcell battery pack amidships under the deck.

LCM-3

Photo is from 2007, with a metal motorized Sherman as cargo. (I later gave up on the idea of trying to animate the ramp. ). A Sherman is not really an appropriate load for a -3. I still have the model, and it still runs well. Its current load is a Dodge 3/4 ton Weapons Carrier, but I am currently building one of the new Tamiya Stuarts to replace it…

RC, how much “too deep” do you figure the hull is? I haven’t found any drawings that give me the actual dimensions, but it does look deeper than my Program 4 Tango hull, and then should be the same.

If it’s close to a foot (hopefully just over), by scale, it could simplify my build considerably.

HooYah;

You should be able to get plans for a 6 boat from One of the wood Boat Model companies. other than that, It’s up in the air. My real boats were 6s but they were modified for oil spill duties. They had the tapered hulls and only one had the Square Screw Tunnels.The other two were Round Tunnel boats.

Plus the bows had been closed up and cut down to accomodate a foredeck. We also had a welded steel grate walkway over what had been the Well-Deck and Oil Recovery tank.

I’ve got 6-boat drawings (remember the 1/12 scale scratchbuild ‘Tango’), I can refer to those when the model kit arrives, but until then . . . (que up the elevator music).

In the mean time, I’m investigating sources of suitable 1/35 scale components that I will need for this build. Unfortunately, some of the things I was hoping for are not materializing. Most of the boat stuff out there in 1/35 is for WW2 PT boats; I’m needing things slightly more modern, i.e. battle lanterns, flush deck hatches, and ship / boat fittings.

Shapeways has some usable stuff, but going through their ‘pages’ is time consuming and frustrating due to the excessive duplication.

Okay; I pulled out the drawings and the transom on the LCM-6 Mod 0, which should be the same as the LCM-3, is 4 foot, 3 inches high. Converting that to 1/35 scale equals 1.457 inches. If the Trumpeter hull’s transom is taller than 1.457", all good; I can build her as converted from a shortened 6-boat or 50’ work boat.

Oh, and TB, the wood boat companies don’t really carry those drawings. Despite the multitudinous options of builds that can be done from the LCM-6, nobody carries a wood kit of one. I don’t understand why, and I’ve been pushing Dumas to try it out, but it’s a slow process.

The difference is 11mm, which is quite a lot. (About 15 scale inches, if my math is right.) It was easy to find the old review- I just googled “Trumpeter 1/35 LCM-3 review”, and it was the first hit. Here’s the link:

https://www.perthmilitarymodelling.com/reviews/vehicles/misc/lcm3/lcm3.htm

RC, "You da man!! Thank you so much, that info is awesome. With those dimensions, and since I’m not using the upper well walls or the bow ramp, the trumpeter could actually be built as a ‘short 6’. Very cool!

Anyway, this is a basic concept drawing of my intentions. It is based on the boat I ran in Hawaii. I have not decided how much interior detail I’ll do as far as the main cabin area goes, but the cox’n flat area should look pretty realistic when done.

After a bit more concept work . . . I will have to wait for the kit to decide on how the cox’n flat will get set up. It’s a deck height issue; ensuring thatthere is enough overhead for engine maintenance, et al.

Also in this drawing you will note the deck extension. This adds about two feet to the beam and much better footing moving around the dive deck and along the sides. The dive deck will be covered by an awning when we are done.

January 21st.

The LCM-3 kit arrived today, and with the scale rulers arriving yesterday, I can get right to work measuring and calculating the corrected scale for this build. I am comparing the kit hull dimensions to the body plan of an LCM-6 Mod 0. The ‘6 mod 0 is basically a ‘3 boat lengthened by 6 feet. The transom on the Trumpeter kit should be 4 feet, 3 inches, but it measures out as 5.5 scale feet. If I measure from the transom keel line to the top of the engine house on the LCM-6 Mod 0 drawing, it comes out to 5.5 feet which is exactly what the LCM-6 Mod 1 transom should be. Therefore, I can build this conversion out like it was from a 50’ workboat or short 6-boat, rather than an LCM-3. How fortuitous! Now I am really glad I ordered this kit vice the other 1/35’s available. For anyone out there contemplating an LCM-6 build, this is the kit to start with. Now if you want an LCM-3 in particular, go with one of the others

Since this is a kit bash, it is appropriate to start by chopping something off. In this case, since the raised engine compartment is not needed, I removed it.

Also, with the craft change and associated deck height change, the engine exhaust and bilge pump overboards are in the wrong places. I went to relocate them then realized not only did they need to move, but there were too many, so I closed up the holes and will place them as needed later. There’s OOPs #1, out of the way!

Continuing with the main deck, I changed out the little lazarette hatch for a larger, flush deck one. Trip hazard eliminated on the dive deck and now you can actually get in there (if it were real, but that’s the whole idea, right?). Then I put in some support for the forward end of the diving deck. Trying to locate some O scale diamond plate for there.

Forward of that I will start with the framing and support of the pilot house structure.

My next question, since I don’t do 1/35 much, is what to use for ‘non-skid’ grit for this scale?

How about some 400 to 600 grit wet/dry sandpaper, or maybe 320. Bonus, it’s black and ready to weather.

I was thinking about a ‘treatment’ I could put over the open deck sections; the dive deck, the side walkways, cabin top, and bow. The flat deck inside the pilot house will be covered by blue Lonmat.

If those areas are in styrene, the common treatment for cast texture, like tank turret, would be to wet the area with Tamiya thin glue, let soften, and stiple with a stiff brush. Might be a little coarse for your needs though.

Worth a sample run. Other than that…