From the Boatshop
by Ron Magen

Lessons Learned

"DECOY" {Wittholtz design}, along with "10-1/2 ft Pointy Skiff" and "12 ft Fisherman’s Skiff" {Bolger designs} bring up an interesting point; which "style" of construction would be most ‘appropriate’ for which season {where weather and temperature are a factor; i.e. unheated garages}.

Cutting of the individual parts is immaterial. That depends on the size of the part - if I do the cutting inside or outside. If outside, or in the garage, it depends on my physical feeling for heat or cold.

Wholly traditional methods rely heavily on fastenings; the adhesives are an adjunct. If it takes a while for them to ‘set-up’ so be it; the parts are already held in place. The only rate limiting temperature is that they don’t freeze or crystallize.

Theoretically they could utilize lighter chines and frames, IF upon basic completion, the hulls were taken off their molds, set upright and epoxy fillets applied to chine and frame areas.[or the molds left in, but the hull removed from the strongback; molds removed after the fillets have set] This would allow COLD WEATHER construction as the temperature sensitive fillets would be applied LAST. At that point construction time WOULD NOT be dependent on adhesive set-up time.

The drawback is the MOLDS, STRONGBACK, and CHINE ‘LOGS’

The "MODERN MATERIALS" method typically uses lighter scantlings, no chine strips {sometimes called "logs"}, few or no permanent fastenings, epoxy / fiberglass sheathed. Because it uses epoxy fillets to hold it’s shape, it really can’t be moved until the hull is finished. Building time is therefore temperature dependent. For timely construction, and good looking non-starved joints, the epoxy must set-up in a reasonable time. The fillet mixture shouldn’t sag or ‘drain away’ before it reaches the ‘gel stage’. For vertical surfaces the minimum is probably about 50 degrees F; 40 degrees F for flat, horizontal ones.

From the catalogs received, most of the plans listed are based on ‘traditional’ techniques.{many are apparently relatively old as well}. They may use ‘modern’ materials like plywood or epoxy, but still rely on multiple frame and chine log construction. Even some that specify "S-N-G" require building assembly forms and molds. Of course, each seems to point to a specific building frame for each boat design. HOWEVER, the " 2 X 10 " frame called out by John Gardner seems to be the simplest. If I don’t intend to go over 12 feet overall, extending it to " 2 X 12 " shouldn’t present a problem. Building a ‘Universal Strongback’ from pressure treated 2 x 6 x 12's and 2 x 4 spreaders, bolted together, would be fairly cheap. { and ‘collapsible’ for space saving storage } The drawback with pressure treated is that it seems to "wet" and warps when it drys. RED CEDAR is available for a little more money, but is lighter, dry, and seems to ‘hold true’. The molds could be cut, in the solid, from 7/16 inch OSB or Waferboard and attached with 3/4 inch plywood ‘angles’ and 2 x 4 ‘blocks’.

A ‘free plan’ included in one of the catalogs, uses construction methods along traditional lines. "Frames" and a "Building Ladder" are called out. Of course a set of "Stitch-N-Glue" plans are available for $35.xx. Again, this points out the value of a ladder frame. Also, NOT all plans have a "Stitch-N-Glue" version. HOWEVER, the methods of the "S-N-G" technique can be combined with the traditional; lighter scantlings can be used.

One of the seemingly ‘universal’ design points in "S-N-G" is DEEP (Sticking far into the interior space from the hull skin) FRAMES. This may be due to the pressures exerted by the sides during assembly, or because there are only a FEW frames. By using square sectioned frames and chine strips, along with clamps and gunnels, more interior room could be achieved.

As a fairly general rule the hull material will be 1/4 inch ply. LAUAN; A-C; Marine Grade; your wallet - your choice. Battens will vary between 1/4 inch LAUAN and ½ inch ply. If Bolger’s "NYMPH" is any guide, the gunnels will tend toward 1 inch thick. This will give a 1-1/4 inch total thickness at the sheer. I would add an inwale or inner clamp to increase this dimension. I like to have the outwale replaceable and hold it in place with drywall screws. SILICON BRONZE { Beautiful!} or MARINE STAINLESS is expensive. A good {1000 hour salt spray certified}, inexpensive alternate is McFEELY’s NO-CO-RODE drywall screws, but the minimum length is 1-1/4 inches.

I’ve gone through the six most popular design catalogs and where there is a gunnel at all this dimension seems to hold.. Jay Benford’s book calls out a 1-1/2 inch half-round in one 11-1/2 ft. design - simple, neat, and gives a 1-3/4 inch total thickness at the sheer.

The options seem to be ‘adjust’ the design or go to the stainless screws. {bronze for clear finish or ‘customer special order’ only} 1 inch, 1-1/4 inch, and 2 inch seem to be the most useful sizes. The 2 inch is basically for skegs and keels. The Deep or Course thread design seems to give greater holding power.

While GLEN-L Marine seems to have the cheapest price for bronze screws, the shipping from CALIFORNIA is a killer!! JAMESTOWN DISTRIBUTORS for an East Coast source of SILICON BRONZE screws and other ‘hardware’. McFEELY’s seems to be the best source for "sheetrock square drive" screws. CLARK CRAFT has WOOD FLOUR, so now I have another source. RAKA MARINE for epoxy & cloth. MERTONS FIBERGLASS SUPPLY for fillers & ‘stuff ‘.


The "problems" with RUBENS NYMPH illustrate what a learning experience is. And the VALUE of patience.

The Aniline dye, on the transoms, was perfect. Once ‘aged’ it didn’t even ‘bleed’ when the epoxy was applied. However, a couple of errors in subsequent procedures had me kicking myself;

FIRST ERROR - adding TO MUCH WHITE ‘filler’ for second, or fill, epoxy coat.

SECOND ERROR - NOT WAITING for a ‘hard dry’ on the varnish before painting the surrounding area with WHITE PAINT.

The epoxy makes a VERY HARD surface. The smoothness depends on the prep work and timing.

The reason for using paint is to protect the surface it covers; from ‘ageing’ and time / weather damage. Varnish, with UV filters, does the same, but allows the surface to show through.

If the material is a "solid" wood, like the Mahogany of the ‘classic’ runabout, then simply using multiple coats of finish is enough.

Paint (OPAQUE paint as opposed to TRANSLUCENT colors), is sort of self-explanatory. Everyone knows it by it’s nature, it’s long history, the books & articles available, and the usually complete instructions on every can. It’s maintenance is simple and logical, and the indications of it’s need of repair or replacement are fairly obvious.

CLEAR finishes over stained wood require a bit more thought; for both the builder and maintainer. In one of Dynamite Payson’s books he says he did a "sacrilegious" thing. He felt the looks of a certain boat would be improved by a Mahogany gunnel, so he grabbed a can of stain and made one !! I don’t have any problem with that !! { want to see the BURMA TEAK "sunning roof" on our Malamute’s house ? }

The ‘problem’ is the future, a rapidly approaching one in the case of an outwale on a working dinghy. I usually make mine of a "consumable" wood, attached with screws, and a simple, cheap ‘teak oil’, finish. Easily maintained or replaced.

However, I like a "classic" Red Mahogany color for my inwales, clamps, transoms, and thwarts. If someone wants to pay the price, or use the boat as a show piece, then by all means use TRUE MAHOGANY. It may be a bit of a search and WILL BE a $TIFF PRICE for 3/4, 4/4, 5/4, etc. stock of practical width.

I need to have my boats SELL, and WANT to see them USED. I also like the touch of the ‘classic’ or traditional. To put these together well takes thought and compromise.

The ‘practical’ material of today is A-C plywood. On either side of that is LAUAN, and imported Marine Grade plywoods - "you pays your money and takes your choice". Bolger, Payson, Devlin, and several others are who I point to for long experience. Typically the A-C’s appearance is plain and uninteresting. It does have a grain surface look as opposed to LAUAN which is rather bland and featureless. [Red Cedar lumber is somewhat like LAUAN in surface appearance] To my sensibilities a translucent coloring turns things completely around.

MY PREFERENCE is for Red Mahogany, but I’ve used WALNUT, SPECIAL WALNUT, BURMA TEAKWOOD, JACOBEAN, and other tones on different projects. Indoors and out. The only caveat for color choice is the logical; dark colors absorb heat. Heat, and sunlight, destroy finishes. That’s one of the reasons for multiple coats of UV sunscreen varnish.

The stain, or dye, changes the ‘character’ of the wood. All well and good. Now the air, the sunlight, the heat, the humidity, etc. can go to work and change what you have "created".

This missive started out with a reason for a finish - to protect. If this boat, or other project, is yours and will be for all time, make a note of the Brand and Color of the stain, then apply a couple of coats of varnish or indoor clear finish, and your done. WHEN future repairs become necessary, and you sand through the stained surface, you’ll know how to ‘repair’ it. Simple enough.

If this is going out of your reach a little thinking is required.

If you have gotten this far you have already decided a bit of maintenance WILL BE REQUIRED. Otherwise you would have painted over everything. Tell the ‘buyer’ the info on the stain and it’s his worry. Maybe O.K. if you’ve used a standard stain right out of the can. BUT what if you have ‘customized’ one, or don’t want to intimidate the buyer?

Back to protection. I’ve used Aniline Dye (alcohol soluble2) for a couple of reasons. Wood penetration without swelling the pores, raising the grain, quick drying, and tone / color control. I didn’t want to close the pores because I want the best epoxy ‘grip’0. NOTE: LET THE DYED WOOD "AGE" for several days.

Apply one or two coats of unthickened epoxy to the dyed wood. You’ll notice how the first coat is absorbed into the wood; open pores. You should now have a fairly hard, fairly abrasion resistant COLORED surface. Add a third epoxy coat if you desire, or the wood seems highly absorbent. The idea, up to this point, is abrasion (sanding) resistance for future maintenance. If it’s warm, and your using a FAST epoxy, you could get on 3-4 coats in a day. Unlike varnish, you do "hot coat" epoxy.

At this point you have a filled, ‘harder than wood’ surface. If you have the patience to let the epoxy ‘cure’ for about a week, you’ll have a HARD surface. If you see ‘whiskers & specks’ on the surface, once the epoxy has set beyond the ‘gum-up sandpaper’ stage, give it a water & drop of detergent wipe down. This will remove any possible amine blush residue. Then give it a light sanding, or rub out. Depending on your technique, the surface may look like it has 5-10 coats of varnish. It may have the LOOK and DEPTH but NOT the UV RESISTANCE. It is harder than varnish but sunlight will degrade it.

Simply treat it as the "next to last" coat of a terrific varnish job. At minimum, --- give it a 220 grit ‘scuff sand’ and a coat of good, hard UV varnish. Then, when THAT coat has dried for 24 hours, give it a 320 grit ‘scuff sand’ and a final coat of varnish.

Some Thoughts About GAP FILLING

One of the problems with the Nymph prototype was large gaps at the chines. Part of this could be resolved by STITCHING specific problem areas. I didn’t do this and had filleting mixture forced through by my pressure, even though I had masked/taped the outside seams. The use of a course, glass fiber added mixture increased the problem. ‘Painting’ the area with unthickened epoxy, then insetting a gauze or OPEN WEAVE drywall tape and allowing it to set-up before filleting should correct this. The ‘trick’ is PATIENCE. And adding at least 2 layers of external fillet. An under layer of course, fibrous material into the seam and undercut; let it reach gel state, then put on an outer or smooth surface layer.