PT 105 by mog - FINISHED - Dumas - 1:30 scale

[mog]

After the Rattlesnake I wanted to do something different.  I have always been interested in the WW2 PT (Patrol Torpedo) boat.   My build will be modelled on PT 105 commanded by Dick Keresey. Yes, believe it or not they made another PTs besides the 109.  The 105 was an 80-foot Elco Torpedo boat 1942, built of spruce, oak and mahogany and made watertight by marine plywood covering.

The Dumas kit 1233, 4 large sheet plans, decent 45-page instruction book, ok pictures, good material list.  Kit is supplied with Mahogany, birch, and poplar ply.   Dumas decided to replace the Mahogany sheet hull planking with 2mm PVC they say it makes for a smother finial finish. OK however if I wanted to build a PVC boat, I would have bought one. I will buy 2mm Mahogany sheets to do the hull planking properly

[GrandpaPhil]

I built this kit several years ago.

 

Replacing the pvc planking with mahogany is definitely a good call.

 

I did not and regretted it.

 

I’m looking forward to seeing progress.

[mog]

For framing and planking the PT boats were built upside down. The prefabricated bulkheads were lined up on a template on the floor of the building shed.  Following this original building style.  A building board (shed floor) is marked out following measurements from the plans to form a template for centring the keel, and lines for placing the bulkheads. The keel and frame 1-6 are placed on the board with the keel and frame 1 and 6 glued to the board. A  lower sheer is added to both sides &  the rest of the frames a dry fitted, checked for alinement, the feet of the frames are glued to the board. Then the chine is added to the upper frames once the lines look good the frames are glued to the keel.

Being a different way to build some trial and error came into play, however after working at getting the whole thing centred it was a simple process, the only error was frame 1 moved during drying and did not fit square to the keel. I used a holding block to help  get  the frame & sheer  as close as stress would allow.  

[mog]

Butterfly Keel and stringers, to keep the shape I had to use planking pins to hold the in place, then removed when set.

[mog]

Bow filler shaped, frame ready for hull planking

 2mm Mahogany sheets and strips for the planking have arrived.  

[mog]

Bottom planking with mahogany. The Dumas plans called for PVC planking using 3 pre-cut sections per side. I went with I full section preside to eliminate seams and get a better shape. Will still have to do some light filling, then plane & sand to shape.

[GrandpaPhil]

Looking good!

[popeye the sailor]

I'm eyeing this kit at the 'somewhat' local hobby store    really like what I see here.  look'in forward in seeing more.  did you trim off all the stringers at the stern and cap it over?

[mog]

I’m really enjoying the build, it’s fun and different. The PTs are great wooden crafts with a famous history. The men who servered on them have great stories, kind of the rouges  of the Navy, no dress whites here.  The stringers, chines and sheers all cut Aft flush with frame 13, a solid transom will be added after hull planking.  

[mog]

UGLY as it looks it’s effective.  I’m quickly learning sheet planking is very different than single strip planking.  You have  more surface to cover, since you are side planking on the frame upside-down, the top seams (bottom edge for the aft sheet is mainly straight, but the bottom edge curves as you go forward.  The screwed in blocks work well for holding the bottom edge firmly in place but given the width and shape of the hull tape lots of tape works best for holding to top edge in place. Before you ask, I did think of using pins to hold it during the drying, but the edges of frames are not made of solid material and will not hold the pins under pressure.  

[Jim Lad]

Just picked up on your build.  She certainly looks good so far.

 

John

[mog]

Planking the starboard side bow with 2mmX 5 mm mahogany strips.  The Bottom of the bow is at a 45-degree angle with the tops at 30.  The PT has sharp lines, the bow forms a fine knife edge First lesson learned here your sides and bottom sheet planking better be dead on straight at the termination point. The starboard side bottom was straight so the fairly even planking However   I was slightly off on the port side so will make corrections before planking the port bottom.  Given I’m working upside down its easy to misjudge the lines. Nothing a file and sandpaper can’t fix.   

[vulcanbomber]

She's an interesting build. Looking good so far.

[mog]

Roughed out the bow planking, now ready shape the lines

[mog]

The wood hulls of a PT had to be very smooth as the Bow would bounce and hydroplane over the water at high speed.  This build is a single layer hull. Will have to remove many more small flaws than I would normally  with a double hull.  The bow being the main area I have rough sanded for shape. Then applied a very light layer of wood filler by hand rubbing it into the bow then rubbing in sanding dust, the idea is not to over fill just rub the plank lines and dips in first.  Doing this with my hands I can fell the shape.   The light rub also brings up the flaws. I will repeat the procedure several times until I get the best surface I can get.  

[popeye the sailor]

what I've done to get a smooth hull is through the use of resin.   a couple coats and some sanding should get her to a smooth finish.  I didn't even use the cheese cloth.........I figured that the mesh would show though.  looks super  

[yvesvidal]

What you do to his hull is a good thing and an insurance to its integrity if you ever float it on a pond or lake.

 

When I was a kid (6 or 7 years old), I built a PT-109 from a wood kit (Can't remember the brand). The hull was made of planks like yours and I glued it with white glue for wood (there was not much choice at that time). The vessel was powered with a small electric motor and after painting it with a medium grey, I took it to the nearest lake. The boat did well for a few minutes, circling all by itself (no RC) and suddenly started to behave like a diving submarine. The motor quickly stopped when submerged and my father and I tried to recuperate the PT-109. When we could grab it, the planks on the bow, had opened like the petals of a flower, allowing plenty of water to rush in. White glue for wood was not really designed for water usage, even when dry. After that, I was always using two components slow curing epoxy glues and the problem never happened again.

 

Yves

Edited October 30, 2019 by yvesvidal

[mog]

Yes white wood glue is not the best stuff in the world, I only use it for mixing with water to treat rigging lines, and stiffen coils & shrouds.  This build for static display so water sealing the hull is not important.  Cabinet makes glue and CA will work.   I would not have thought too use  2 part epoxy or resin  However I do appreciate all the suggestions,  good ideas always come in handy sooner or  later 

[Jim Lad]

In such a short time, various odd bits of wood have become a small ship!

 

John

[mog]

Filled and shaped   The lines fit the templates I used about as close as I can get, the hull is smooth.

Working my next move. At this stage the plans call for cutting the hull off the board and shape the top for laying the deck, I plan to lay a sub deck then plank.  The question is WHAT is the next move?

I need to seal the hull so it will  be very smooth and take primer and paint   I have tossed it out around several sites and gotten some good ideas from excellent builders  Resin, bondo, straight primer , spay on a coat of lacquer then prime just to name a few. I think I will cut the hull from the board prep the top and lay the sub deck, then work out best way forward on the hull.  Any thoughts on this would be helpful

[mog]

Hull cut from building board,  up righted  and placed on  a stable stand to handle the deck prep

[mog]

Completed removing the centre hatch, with a static display I guess it’s not a must to remove, however I think it will be easier to work the superstructure off ship

There are 3 hatches 2 forward 1 aft, built the boxes in case I decide later to go open hatches. Will work the subdeck next, I have ordered the planking wood.  

[popeye the sailor]

is there any sort of well where the structure is located?  if so,  you could frame it out,  as well as these other wells.

[mog]

Thanks  to popeye I rechecked the drawings, and found 2 more hatches.  Then talked with two of best PT boat experts on the planet. My  Thanks to Jeff Davison from pt103.com who sent detailed drawings. 

[mog]

Sub deck in. Planking wood has arrived. Next 3 steps shape edges of subdeck., coat the hull with a sealer   filler mix to get the smooth surface needed for primer. Plank the subdeck.

[popeye the sailor]

was any additional planking supplied in the kit?  seems odd that you'd need to order some..........most do because they don't like what is supplied.  the hull is looking super  

[mog]

The Dumas kit is a single deck not calling for planking wood.  However early PTs 1941,42 had planked decks. I always like to plank over a solid subdeck, so I ordered strips in the size I wanted to use.  With all my builds I like ordering my own wood for specific tasks and look. a good part of the kit wood goes into the general supply for building.  So I give Cornwall boats allot of money.

[James H]

Your method of construction with the angled timbers looks just like how these were built!

[mog]

I have spent allot of time talking with experts on the PTs, they kindly have provided me with a vast amount of highly detailed plans and information. It’s important to me that I do the boats and there crews memories justice with this build. Only hope my skill level is up to it, I’m ok with the wood, but the real test will come when working with the weapons and metal, I never fabricated metal before, so the learning curve will be steep.

[mtdoramike]

If I were to build this kit and decided not to use the PVC sheets for the hull, I would opt for a cheaper wood and would probably use strip wood rather than sheets because the strip wood planking would be much easier to apply, it might take a bit longer, but to me it would be easier. This boat is really meant to be painted the military colors and it would be a shame if not a crime to paint mahogany. I would most likely opt for balsa, which would be covered with fiber glass cloth and resin.