Jaager

Unlike plastic, it is neigh on to impossible to totally ruin a wooden ship kit.  Worse comes to worst, all of the material can be replaced with the natural material from outside sources, and started over as scratch.  It is better schooling too.
 
One of the tricks with carving is to use tools that work well. 
For more than light removal, StewMac has a pair of small razor files that are peachy keen.
For the sort of sanding that the hull needs, it is probably better to always have a wood backing on the sandpaper. 
Rubber cement - both surfaces coated, allowed to dry, and joined, fixes the paper to the backing and makes for easy renewal.
No matter how badly the hull looks,  it will still look better than any POB hull - unless the POB hull is totally filled between the molds.   And if that is done, it is essentially the same as a carved hull.
It is difficult to irreversibly damage a solid wood hull.  If too much is removed, the loss can be replaced.
If it is just a little, wood flour mixed with PVA makes a very strong layer, but it will be tougher to remove than the original wood after it sets up.   For a deeper patch, scab a layer of wood veneer - Pine works.
When you get the shape to match your templates, even if it is ugly, that is easy to hide.
The kit may offer this suggestion, but a solid carved hull makes an excellent support for a layer of actual planking.
The planking wood should be thin and of a scale appropriate species of hardwood.  Being thin, the planks can be properly spilled by using a steel straight edge and a sharp knife.  Since the hull is being gridled beyond its dimension, thin is best.
Using an appropriate species of wood can turn a chore into a joy. 
The model will look better.
 
 

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 
The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.

Before there was synthetic organic chemistry , begun in Germany in the latter part of the 19th century,  paint pigments were naturally occurring minerals.  The minerals are the same color today,  so there is not much guess work about the colors and the pallet is somewhat limited. 
 
In their early monographs, ANCRE included a page with patches of colors.
 
 

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 
The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 
The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 
The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 
The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.

I appreciate the intended humor. 
I will use this as a gate though.
I very much resist using aerosol anything.  The process turns materials that would not otherwise be available to breathe into particles that gain easy access to our alveoli.  It increases the concentration of volatiles  that are able to get there.
I use lacquer -  the brushing version - to coat my patterns.  It sort of simulates Mylar.  
There are two flavors of lacquer thinner. There is the original and there is "Green".  Both contain a rogues gallery of organics that are better not allowed to float around in our bodies.  From just brushing it, both solvents are fierce to breathe and to the eyes.  Only using it outside works for me. 
The spray version would not only increase the concentration of the solvents in the air, it would allow the actual particles of lacquer itself to be small enough to breathe.   I know - spray booth - and/ or space suit - can remediate most of the effects.  I prefer to not create situations where remediation is necessary if I can avoid it.  
The brushing lacquer is "designed" or "by its nature must"  leave a thick layer - that is the whole point in what I use it for.
 
I know spray lacquer can leave a thin protective barrier - I played a trombone thru age 19.  Lacquer is used to keep the brass shiny and in the hands of teens in travel and outside conditions,  the finish often needs renewal.  But, professionals applied it in "supposedly" ( it was the 60's ) safe conditions.  At home, it fails my cost vs benefit evaluation.

It does take on a white color in patches, so it may well be water and not oxygen. 
To speculate, if it is water, then it is a physical mixture instead of chemical reaction.  If so, then if the flakes could be dehydrated, then the flakes would be restored.  I wonder if a low heat oven would drive off the water without degrading the shellac?

In my hands, the flake form of super blonde shellac has a shelf life.  When it is too old, it does not easily dissolve.  The flakes fuse together and the lot that almost instantly dissolves when new. It will still be a gel at the bottom of the alcohol container after a week,  if you have had the flakes for a few years.  The flakes are sold in plastic bags, which does not exclude oxygen very well.  
 

There are several chemical bonding agents under the Elmer's umbrella.   If it is white PVA that you used, then if the surfaces were close enough together, then the PVA polymers would be more than strong enough.  PVA is stronger than cellulose to lignin in any species of wood.  In Balsa the wood itself just barely holds itself together.  If your joint tolerances were close enough, it is probable that the wood itself was the site of failure.
 
I suspect that kits that do come with sails do so for marketing reasons.  What is provided is not appropriate to the scale of the model.  Unless you are at a scale above 1:48, I doubt that any woven fabric has thread that is fine enough or a weave that is tight enough to meet scale requirements.
 
Speculation:  Kit manufacturers who are serious about historical accuracy do not provide sails -  those that do probably are providing a subject that has as much fiction and fantasy as historical accuracy.
 
Wooden ship model kits are from an evolutionary development track that expected anyone who is serious about the subject would add or replace with scratch built components.  The earliest kits were little more than a crudely carved hull, plans, and a push into scratch.  
 
Beyond a true beginner's kit - the focus of a wooden ship model kit instructions should be on accurate plans, with options for possible scratch augments,  as much information on the individual "What" as practical,  with the expectation that the builder will already know the "How" or will have the ability to dig it out.  The instructions should have a bib. and Net links to make a good start on the search for the "How".
 
One of the advantages of a wooden ship model kit is that the raw material is easy to obtain from multiple sources.  In most instances, with mass market kits, the material obtained from secondary sources is superior to what is provided with the kit.  Doing this should be a source of pride, additional skills, and confidence.

I appreciate the intended humor. 
I will use this as a gate though.
I very much resist using aerosol anything.  The process turns materials that would not otherwise be available to breathe into particles that gain easy access to our alveoli.  It increases the concentration of volatiles  that are able to get there.
I use lacquer -  the brushing version - to coat my patterns.  It sort of simulates Mylar.  
There are two flavors of lacquer thinner. There is the original and there is "Green".  Both contain a rogues gallery of organics that are better not allowed to float around in our bodies.  From just brushing it, both solvents are fierce to breathe and to the eyes.  Only using it outside works for me. 
The spray version would not only increase the concentration of the solvents in the air, it would allow the actual particles of lacquer itself to be small enough to breathe.   I know - spray booth - and/ or space suit - can remediate most of the effects.  I prefer to not create situations where remediation is necessary if I can avoid it.  
The brushing lacquer is "designed" or "by its nature must"  leave a thick layer - that is the whole point in what I use it for.
 
I know spray lacquer can leave a thin protective barrier - I played a trombone thru age 19.  Lacquer is used to keep the brass shiny and in the hands of teens in travel and outside conditions,  the finish often needs renewal.  But, professionals applied it in "supposedly" ( it was the 60's ) safe conditions.  At home, it fails my cost vs benefit evaluation.

I appreciate the intended humor. 
I will use this as a gate though.
I very much resist using aerosol anything.  The process turns materials that would not otherwise be available to breathe into particles that gain easy access to our alveoli.  It increases the concentration of volatiles  that are able to get there.
I use lacquer -  the brushing version - to coat my patterns.  It sort of simulates Mylar.  
There are two flavors of lacquer thinner. There is the original and there is "Green".  Both contain a rogues gallery of organics that are better not allowed to float around in our bodies.  From just brushing it, both solvents are fierce to breathe and to the eyes.  Only using it outside works for me. 
The spray version would not only increase the concentration of the solvents in the air, it would allow the actual particles of lacquer itself to be small enough to breathe.   I know - spray booth - and/ or space suit - can remediate most of the effects.  I prefer to not create situations where remediation is necessary if I can avoid it.  
The brushing lacquer is "designed" or "by its nature must"  leave a thick layer - that is the whole point in what I use it for.
 
I know spray lacquer can leave a thin protective barrier - I played a trombone thru age 19.  Lacquer is used to keep the brass shiny and in the hands of teens in travel and outside conditions,  the finish often needs renewal.  But, professionals applied it in "supposedly" ( it was the 60's ) safe conditions.  At home, it fails my cost vs benefit evaluation.

It does take on a white color in patches, so it may well be water and not oxygen. 
To speculate, if it is water, then it is a physical mixture instead of chemical reaction.  If so, then if the flakes could be dehydrated, then the flakes would be restored.  I wonder if a low heat oven would drive off the water without degrading the shellac?

In my hands, the flake form of super blonde shellac has a shelf life.  When it is too old, it does not easily dissolve.  The flakes fuse together and the lot that almost instantly dissolves when new. It will still be a gel at the bottom of the alcohol container after a week,  if you have had the flakes for a few years.  The flakes are sold in plastic bags, which does not exclude oxygen very well.  
 

I have nothing to suggest about why your polyurethane will not polymerize. 
 
I do not think lacquer is an appropriate clear finish for any ship model that is not a toy.  It is out of scale in thickness and is used to build up a thick layer and is usually glossy.  Glossy is not scale appropriate for 1:60.
 
Polyurethane has more who favor it than eschew it here.   I am firmly in the eschew camp.
It is a modern synthetic plastic.  It is great for bar tops and wooden floors. 
I see anything plastic (except for PVA) as being against the spirit of a wooden vessel built before 1860.
A traditional clear finish that is easy to use, allows extensive control, and is compatible with almost everything is shellac.
I can be applied using cloth or a brush.  It has an excellent reverse gear. Ethanol (95%) or isopropanol (100%) (91%?) or Methanol (if you can get it) makes it go away.   I am betting it is not so easy to remove sticky polyU.
 
Premixed shellac comes as "clear" and amber.   Shellac flakes do also, plus there are darker shades - shades that are not dewaxed or slightly dewaxed.   If it is not enough, traditional varnish, poly, lacquer, both types of paint can be used to coat over it.

Home Depot has paper cones with windows,  nylon bags, and covers for 1 gal cans.

I have nothing to suggest about why your polyurethane will not polymerize. 
 
I do not think lacquer is an appropriate clear finish for any ship model that is not a toy.  It is out of scale in thickness and is used to build up a thick layer and is usually glossy.  Glossy is not scale appropriate for 1:60.
 
Polyurethane has more who favor it than eschew it here.   I am firmly in the eschew camp.
It is a modern synthetic plastic.  It is great for bar tops and wooden floors. 
I see anything plastic (except for PVA) as being against the spirit of a wooden vessel built before 1860.
A traditional clear finish that is easy to use, allows extensive control, and is compatible with almost everything is shellac.
I can be applied using cloth or a brush.  It has an excellent reverse gear. Ethanol (95%) or isopropanol (100%) (91%?) or Methanol (if you can get it) makes it go away.   I am betting it is not so easy to remove sticky polyU.
 
Premixed shellac comes as "clear" and amber.   Shellac flakes do also, plus there are darker shades - shades that are not dewaxed or slightly dewaxed.   If it is not enough, traditional varnish, poly, lacquer, both types of paint can be used to coat over it.

Everything written about shellac that I've ever read contains the caveat that it has a limited "shelf life." I'm sure at least some of these articles have been written by experts. I've always used Zinsser's "Bullseye" brand pre-mixed "orange" (amber) or "white" (clear) shellac in quart cans. All I know is that I've never perceived any deterioration of the product over the passage of time and, in some instances, it took me several years to consume a quart of the stuff. I've certainly had it thicken a bit due to the evaporation of the alcohol solvent, which is easily resolved by simply adding more alcohol, but I've never seen any of the Zinsser's Bullseye shellac "go bad" sitting on the shelf. As this stuff probably has to set on the shelf in the store for a long time before it's sold, perhaps Zinsser has found some additive that solves the short shelf life problem? I don't know.
 
What i do know is that shellac is one of the handiest materials I know for modeling. It dries very quickly. It's easily thickened by just letting a small amount sit in the open air for the alcohol to evaporate. Thinned shellac is an excellent wood finish that can provide the entire range from matte to high gloss, depending on how thick you wish to apply it. It's also one of the most moisture resistant coatings available. It can be hand-rubbed to a perfect finish ("French polishing") or, applied thin, can serve as an invisible matte sealer beneath any other coating. It can also be used to stiffen rope to form catenaries in rigging and seal rigging knots which can later be easily undone if needed. Thickened shellac is an excellent adhesive. Shellac is archival material that will last for centuries and is easily dissolved and removed with common alcohol. It's also non-toxic (except for the denatured alcohol its dissolved in. Shellac is used in confectionary making to give a gloss to candies such as jelly beans.) And, last but not least, it's readily available in paint and hardware stores and relatively inexpensive.
 
I can't see what's not to like about the stuff. 

I have nothing to suggest about why your polyurethane will not polymerize. 
 
I do not think lacquer is an appropriate clear finish for any ship model that is not a toy.  It is out of scale in thickness and is used to build up a thick layer and is usually glossy.  Glossy is not scale appropriate for 1:60.
 
Polyurethane has more who favor it than eschew it here.   I am firmly in the eschew camp.
It is a modern synthetic plastic.  It is great for bar tops and wooden floors. 
I see anything plastic (except for PVA) as being against the spirit of a wooden vessel built before 1860.
A traditional clear finish that is easy to use, allows extensive control, and is compatible with almost everything is shellac.
I can be applied using cloth or a brush.  It has an excellent reverse gear. Ethanol (95%) or isopropanol (100%) (91%?) or Methanol (if you can get it) makes it go away.   I am betting it is not so easy to remove sticky polyU.
 
Premixed shellac comes as "clear" and amber.   Shellac flakes do also, plus there are darker shades - shades that are not dewaxed or slightly dewaxed.   If it is not enough, traditional varnish, poly, lacquer, both types of paint can be used to coat over it.