Jaager

As for steam bending, Holly is really good at this.  Unless you have or have a relative with Holly to harvest,  access to a kiln and can wait until Winter to cut down the trees,  you will have to use the snow white commercial stock.  For what you want to do, using store bought Holly would be a bit like making counterfeit pennies using Silver and spending it like a penny.

Ash is long lasting on land even if it is not very much protected. At least the shovel and mattock handles of tools I got from my contractor grandfather held up.  They had spent time in the rain and sun.  The summer wood was proud of the spring wood.  Bare wood, they were not pretty, but they were plenty strong.
For a display scale model, for any visible parts, Ash, Oak, Hickory have grain that is too stark and pores that are too large.  If painted, an extra step using a sealer to fill the pores is needed if a smooth surface is a target.  For structure hidden inside, these should work.
For your purpose,  I am thinking Ash should work just as you hope.  The epoxy will take care of any out of scale grain or open pore characteristics, especially if you finish with paint and not clear coat.

Andy,
When I get OCD, I prime end grain with 50:50 PVA:water.  I blot any excess.  It then is allowed at least 24 hrs to polymerize.  It is for instances of end grain to end grain bonds.  This is never a strong bond, but pre filling the open spaces with plastic could help.
For planking - no dilution is needed or wanted.  Use quality PVA.  Titebond II has worked well for me.  Use a damp rag or paper towel to remove any squeeze-out.  I cannot think of any wood to wood bonding situation where dilution of PVA would have any advantage.  I imagine only bad results from doing it.
For natural fiber rigging that comes off the ropewalk,  bookbinders neutral pH PVA diluted 50:50 is a treatment for the line while hanging under weights.

Hank,
Keep him seriously bribed.  Saw dust is messy but easy to clean up; and not critical if you miss some.  Steel kerf and shavings are something else.  They can play havoc with a machine.  When a job is finished, a mill or lathe needs serious and time consuming disassembly,  messy cleaning, and reassembly.  Steel shavings are really unpleasant to deal with.  And the oil...., I use laxative mineral oil for way oil, but it is still a chore to remove.

A shallow search indicates that Spain did not mine asphalt for another 200 years, so the pitch was probably "Pine" tar.  Dark, but not 000,000,000 black.   The proportions of dark brown and tallow are maybe lost forever or in the Spanish archives,  but see what 50:50  dark brown to tan nets you.

The tops of your moulds are sort of swinging in the breeze. Filling between them is a better idea than even with those models with a central spine that gets close to the deck beam level.
See if there is a local wood workers guild.  You can probably get more help with access to serious power tools than would be imagined.
The alternative - a pack of Midwest Basswood sheets 1/4"  and  a smaller supply of 1/16" sheets.
A fret saw should work.  A good base helps.
Here is examples of what I am discussing as stock:
https://www.dickblick.com/items/33300-9412/
https://www.dickblick.com/items/33300-9602/

It seems fairly expensive to me.   I get acceptable results from a EuroTool DRL 300.  I have only used wire gauge bits with it.  I added an XY table that cost more than the drill,  but now I see that I could have gotten the same thing from Ali Express for ~$40.  The price has jumped from $80 to $110.  Tariff result is my guess.   I would sooner use a $100 machine if I was going to break the rules and use it for lite milling on wood, than a $350 machine.  Neither has bearings for lateral force.   I also use a momentary foot switch with it.  For drilling wood, I do not see the benefit of a bells and whistle level speed control.  A sharp cutting edge is more important.  Isn't the speed control a metal being worked thing- Al vs Fe vs CU?
If you are going to use it to make tools and will be milling metals, a for real milling machine would be reasonable expenditure.  For wood, you do not even need accuracy. You do need precision though - i.e.  once you determine what and where, that it repeats doing that exactly the same every time.  My DRL-300 will do that.  My sin is that I use a bit until it bends or breaks.  Some burning in a #70 hole does not bother me.
 

Hank,
Sort of off the wall, 
1) I first thought that by Micro-Make, that MM had a drill press as part of their rebranded line of Kaleas DC tools.  The right angle sander I like -a lot.  The belt sander does jobs that are difficult otherwise, as long as it is held with a wood spacer to stop it throwing the belt, which takes about a minute otherwise.  I am not sure about the other tools.  No drill press though.
2) USS Pennsylvania - I first thought of the 1830 120 gun liner-  an absolute monster,  it has all of the beauty and grace of a Stalin Era high rise apartment building with spars and sails.
 

It seems fairly expensive to me.   I get acceptable results from a EuroTool DRL 300.  I have only used wire gauge bits with it.  I added an XY table that cost more than the drill,  but now I see that I could have gotten the same thing from Ali Express for ~$40.  The price has jumped from $80 to $110.  Tariff result is my guess.   I would sooner use a $100 machine if I was going to break the rules and use it for lite milling on wood, than a $350 machine.  Neither has bearings for lateral force.   I also use a momentary foot switch with it.  For drilling wood, I do not see the benefit of a bells and whistle level speed control.  A sharp cutting edge is more important.  Isn't the speed control a metal being worked thing- Al vs Fe vs CU?
If you are going to use it to make tools and will be milling metals, a for real milling machine would be reasonable expenditure.  For wood, you do not even need accuracy. You do need precision though - i.e.  once you determine what and where, that it repeats doing that exactly the same every time.  My DRL-300 will do that.  My sin is that I use a bit until it bends or breaks.  Some burning in a #70 hole does not bother me.
 

Allen,
What are the tools that you have access to?
Balsa seems to be the default favorite.  It is soft and readily available.  It is weak, really poor at holding planking pins, dowels, trunnels. It is no joy to work,  messy,  apparently something that your respiratory tract finds objectionable.
Basswood is available in sheets ranging from 1/32" to 1/4".  It is strong enough to hold fittings.  It carves well and is easy to hand cope.  You could also maybe add an addition to your house for what Midwest wants for enough to do the job you want it to do.
If you have access to a 10" table saw or a 14" bandsaw - to slice (resaw) pieces that will sum up to fill the gaps:
Yellow Poplar if you are determined to use a hardwood.
Pine from 2x4 or furring strip bins at your local builders supply.  Select, watch for checks, avoid species with sap runs,  Fir if you gotta, but Pine is more pleasant to work.
My choice would be Pine.  Balsa should be an eleven foot situation.
 
I looks like common way to ad the filler is to fit the pieces of filler between the moulds using a horizontal orientation.   The end grain against the moulds, cutting to fit is easier.  This also places the onus of bulk shaping the filler while it is in place on the hull.
 
Think vertical.  Think widths similar to actual frame widths,  or 1/4" each at most.
Think shaping the rough outside curve on each layer while it is 1/4".  The inside can be any shape, just make sure all of the layers between two moulds have some inside overlap.   Bamboo skewers can be used to connect the layers and make sure they line up. 
Use the mould pattern for the larger mould to get the rough outside shape for each layer.
Have the position for at least two skewer dowels on each layer.
Glue them all together.  Dry fit them between their moulds.  If there is a gap, poster board and paper can be used to make up a narrow space.
Draw the down bevel ( the bow or stern end)  and the actual up bevel (the mid ship end). The plan shape will be fat because of the bevel on the mould on the mid ship end, But it has still allowed most of the shaping to be done on thin pieces. 
Remove the filler and do the beveling on the loose section.  Now it can be glued in place between the moulds and only fine shaping is needed.
 
If you have ambition and ability to mill your own stock, now is your opportunity to be a ghoul and see if any neighbors have lost fruit trees or ornamental Pear,  Box,  Hawthorn,  Hornbeam,  Honey Locust.   Search our Wood forum for what to do with the logs.
 

You have already planked a POB hull?
The moulds are few in number and widely spaced?
This is a two layer planked hull and you are shaping the first layer?  The planking wood is thin and flexes under force?
 
As Wefalck writes,  the usual practice is to use filling material between the moulds, shaped to hull lines before any planking is applied.  Done correctly, only one layer of planking is then required.
It has been my impression that on a two layer hull, the first layer is relatively stiff and the display layer id often a thin decorative species veneer.  (To my eye, often a species with out of scale grain and open pores, but never mind that.)  Did you plank the first layer using the veneer?
 
Now, to your present situation:  epoxy sounds like a messy and much less than ideal solution.  I would obtain a supply of wood veneer that is thin enough to bend inside the 90 degree arc amidship. 
Use a sharp knife to cut popsicle stick wide or narrower strips and PVA glue a layer or two inside in a vertical orientation.  No compatibility problems.

Rather than bolt tools directly to my bench top,  I added a woodworkers vise under the front of the bench - a cheap HF vise that wants to rack when tightened, because the tolerances are from poverty.  But I do not do full size wood projects and it is not needed for that.
I use a 2x12 to make a tool base.  I use lag bolts to secure the tool and to mount a second piece of 2x12 to the front of the base and make it long enough to engage the vise.   
I can store the tools under the bench and have the whole bench open when I need it.   I can interchange a grinder,  machinist's vise,  9" band saw.  
There are open wrenches specific to the saw.  I fixed a spring clamp that is for dowels used for clothing hangers to the top of the base.  It holds the wrenches, but easily turns them loose.   Holes in the top hold tool specific Allen wrenches.
 
It looks like a 2x12 may be difficult to source, but the width is good to have.

Rather than bolt tools directly to my bench top,  I added a woodworkers vise under the front of the bench - a cheap HF vise that wants to rack when tightened, because the tolerances are from poverty.  But I do not do full size wood projects and it is not needed for that.
I use a 2x12 to make a tool base.  I use lag bolts to secure the tool and to mount a second piece of 2x12 to the front of the base and make it long enough to engage the vise.   
I can store the tools under the bench and have the whole bench open when I need it.   I can interchange a grinder,  machinist's vise,  9" band saw.  
There are open wrenches specific to the saw.  I fixed a spring clamp that is for dowels used for clothing hangers to the top of the base.  It holds the wrenches, but easily turns them loose.   Holes in the top hold tool specific Allen wrenches.
 
It looks like a 2x12 may be difficult to source, but the width is good to have.

You have already planked a POB hull?
The moulds are few in number and widely spaced?
This is a two layer planked hull and you are shaping the first layer?  The planking wood is thin and flexes under force?
 
As Wefalck writes,  the usual practice is to use filling material between the moulds, shaped to hull lines before any planking is applied.  Done correctly, only one layer of planking is then required.
It has been my impression that on a two layer hull, the first layer is relatively stiff and the display layer id often a thin decorative species veneer.  (To my eye, often a species with out of scale grain and open pores, but never mind that.)  Did you plank the first layer using the veneer?
 
Now, to your present situation:  epoxy sounds like a messy and much less than ideal solution.  I would obtain a supply of wood veneer that is thin enough to bend inside the 90 degree arc amidship. 
Use a sharp knife to cut popsicle stick wide or narrower strips and PVA glue a layer or two inside in a vertical orientation.  No compatibility problems.

I must be seeing this wrong in my mind, because I can imagine a struck harpoon, a whale managing to submerge, and a harpooner dragged  overboard and trailing behind under water like a tin can behind a newly weds' car.

You have already planked a POB hull?
The moulds are few in number and widely spaced?
This is a two layer planked hull and you are shaping the first layer?  The planking wood is thin and flexes under force?
 
As Wefalck writes,  the usual practice is to use filling material between the moulds, shaped to hull lines before any planking is applied.  Done correctly, only one layer of planking is then required.
It has been my impression that on a two layer hull, the first layer is relatively stiff and the display layer id often a thin decorative species veneer.  (To my eye, often a species with out of scale grain and open pores, but never mind that.)  Did you plank the first layer using the veneer?
 
Now, to your present situation:  epoxy sounds like a messy and much less than ideal solution.  I would obtain a supply of wood veneer that is thin enough to bend inside the 90 degree arc amidship. 
Use a sharp knife to cut popsicle stick wide or narrower strips and PVA glue a layer or two inside in a vertical orientation.  No compatibility problems.

You might try tissue paper - the stuff used to wrap pretentious gifts - or rag bond paper for thick - to simulate cloth.  PVA will bond it and shellac will fill the pores and take any paint.

Home Depot has free sample squares of Vinyl flooring.  As an intermediate between a tool base and a bench top, it may absorb some vibration even if it is under heavy clamping pressure.  I used this in-line for my Erector Set type mount for my 1/3 hp motor for the drum sander.  The cost was right - just a quarter turn on the nut.

I use a 9" bench top with the finest available blade (1/8") for scroll cutting.  I just need to get sort of close.  The blade has teeth with set.  There is significant kerf and the face of the cut is rough. As long as the blade is sharp and the blade run is not jammed with scrap, the cut goes quickly.  I added a Carter Stabilizer and with it I am not limited in radius. I can turn the work on a lot less than a dime.  It about doubles the cost of a low end 9" saw.   If you want to bull it out and finish with a disk or drum sander, a bench top band saw does the trick.  I would not attempt anything fine or delicate using it.  I would not use it for much of anything else though.  If you intend to get into the milling from planks or logs, a bench top band saw is a very poor choice.  That is a go big (14") or go home situation,  unless you enjoy frustration.

I use a 9" bench top with the finest available blade (1/8") for scroll cutting.  I just need to get sort of close.  The blade has teeth with set.  There is significant kerf and the face of the cut is rough. As long as the blade is sharp and the blade run is not jammed with scrap, the cut goes quickly.  I added a Carter Stabilizer and with it I am not limited in radius. I can turn the work on a lot less than a dime.  It about doubles the cost of a low end 9" saw.   If you want to bull it out and finish with a disk or drum sander, a bench top band saw does the trick.  I would not attempt anything fine or delicate using it.  I would not use it for much of anything else though.  If you intend to get into the milling from planks or logs, a bench top band saw is a very poor choice.  That is a go big (14") or go home situation,  unless you enjoy frustration.

I use a 9" bench top with the finest available blade (1/8") for scroll cutting.  I just need to get sort of close.  The blade has teeth with set.  There is significant kerf and the face of the cut is rough. As long as the blade is sharp and the blade run is not jammed with scrap, the cut goes quickly.  I added a Carter Stabilizer and with it I am not limited in radius. I can turn the work on a lot less than a dime.  It about doubles the cost of a low end 9" saw.   If you want to bull it out and finish with a disk or drum sander, a bench top band saw does the trick.  I would not attempt anything fine or delicate using it.  I would not use it for much of anything else though.  If you intend to get into the milling from planks or logs, a bench top band saw is a very poor choice.  That is a go big (14") or go home situation,  unless you enjoy frustration.

You might try tissue paper - the stuff used to wrap pretentious gifts - or rag bond paper for thick - to simulate cloth.  PVA will bond it and shellac will fill the pores and take any paint.

Lin,
I have an interest in the Leda class frigates.   To be specific, HMS Shannon.  I have lofted the timbers.  I also lofted USS Chesapeake.  I thought that the pair would be interesting together, as singleton stand alone POF.  I am not into diorama.  Because Leda is a copy of L' Hebe and La Venus is a sister of Hebe, I considered ANCRE Venus and what with the POF supplement I thought that I had my in.  But, for my method, they still whiffed on the plans.  I used the NMM plans for HMS Leda, as beat up as they are.
Which plans did you use to build the hull?
Did you build the hull - POF,  POB,  solid carved?
 

Let me first supply this caveat, I have never built a POB hull. In deed, I went to some effort to demonstrate an alternate method to POB to fabricate a hull that gets you the place where the real planking of the hull can begin.  I jumped in because when I looked at C. Poison's pix of POB components and saw no lines to site the moulds properly on the spine, that shocked me.  Your model does have them.
 
But I do not believe that the height of the central spine has anything to do with the deck.  It would be more or less useless to have one line of pseudo carlings at the center.  Indeed, has it exists, it is a problem for hatches and masts.  It is neigh on to impossible to have the mast below the main deck be long enough to easily get the correct rake.  It just does not extend to a mast step on the keelson.   You do want to test that height and camber of the moulds will support a sweet and proper run of deck planking.  Use a wooden batten to do this. ( I am guessing that your deck is a sheet of basswood, instead of actual planks.  But even this does not like misalignment and dips. ) 

If the line that is on the center spine and on each of the moulds is from the kit mfg, that is the reference/register line to assure that the moulds align properly.  Not only is the shape of the hull, and the run of the planking dependent on this being correct but the top is what replaces the deck beams.
The moulds look to be sparse enough in number and far enough apart that two layers of planking will be needed.  This means that the bottom of the moulds must be well above the rabbet for the actual planks.  Some ships had a garboard that was twice the thickness of the bottom planking and the outface was dubbed/adzed smooth and some had a step down.
 
If the outer planking comes in too high, a wedge shaped plank at the spine can fill the gap and allow the outer plank to seat in the rabbet.