1954 Penn Yan Captivator: How to Seal Bottom Seams using Thixo Flex

1954 penn yan captivator seal seams

Sorry about the behemoth compressor firing up in the “background.” With five preservation projects fully engaged right now, I cannot simply shut the shop down when I shoot a video.

Finally, I am confident we have solved a chronic wood boat preservation conundrum, “My boat has an original bottom with open seams. I do not wish to, or in the case of a Striptite hull cannot, install a True 5200 Bottom. Nor do I typically drop her in the water where she lives all season. What are my options short of waiting for her to swell each time we launch and hope to use her?”

Hmmm …. Our stock answer has been, “Use Interlux Seam Compound for below water applications. It will remain elastic, compressible and able to withstand the swell-shrink cycle, even if the movement is miniscule, without overly compressing the wood on each side of the seam.” Save for two cases where a boat came back for new bottom paint and we found that some of the Seam Compound had become hard and brittle, I am still comfortable with it as a product that solves the problem. However….

OMG! Even when heated, it pays very, very poorly, and will fight you every inch of the way. What’s worse than all the time involved, Interlux recommends three applications.

There must be something better, especially in terms of ease and time cost of application.

I recently answered a query about the best material to use when sealing lapstrake topside strake seams with a small fillet. Our practice to date has been 3M5200, as long as the fillet is tiny, tiny in cross section, and any feathers beyond it are removed. One of you answered simply, “Use West G-Flex and you will be good.”

Hours and hours of subsequent research tells me that this person is correct. However, while two-part G-Flex is supplied in squeeze bottles and quart cans, Jamestown Distributors offers Thixo Flex, a TotalBoat brand version that is also two-part, satisfies G-Flex’s criteria for adhesion and lasting elasticity and is packaged in 10 oz. caulking tubes along with a mixing tip that delivers material in a fine stream that comes out having been mixed precisely.

Our tests, albeit only over several weeks rather than several years, and painfully small sampled, delivered a bond that is flexible and simply cannot be torn apart unless the wood fibers fail. After paying a seam’s worth, I use a super flexible putty knife to drive the material into the seam. (A plastic spreader may work as well, but I prefer the putty knife.)

The waste is scooped and spread into the next seam.

I should be able to finish the Captivator’s bottom spending about 2+ hours per side. Paying Seam Compound would take time measured in days, by contrast.

Once the Thixo Flex has cured, and after we’ve checked for any pin holes or holidays, we will sand the cured residue off the planks and seal the entire bottom with three full coats of Smith’s Clear Penetrating Epoxy Sealer.

Priming it with three coats of Pettit Tie Coat Primer 6627 will follow.

We must install the new transom bracing and transom before we can finish paying TotalBoat Thixo Flex into the bottom seams, however.

Step-by-step…

1937 Lyman Cruisette – How-to Strip Varnish & Stain

1967 lyman cruisette how-to stain varnish

Stripping paint and varnish from antique and classic wood hulls must be the least rewarding element of their preservation. It’s all about getting it off.

That it is a cliché’ is immaterial. Preparation is 95%+ of great wood boat preservation. Cleaning the wood completely, until all traces of penetrating stain or surface coatings have vanished, is the cornerstone of thorough and complete preparation.

And, what with grain typically running in multiple directions, great care must be taken that the scrubbing involved here does not raise a forest of cross-grain scratches in the process. While we do sometimes reach for the heat gun when stripping paint, chemical stripping is our go-to method, especially when stripping bottom paint. The chemical stripper encapsulates any lead that might be released by the stripper, where there is danger in using a heat gun that exceeds 1,100 degrees Fahrenheit, the temperature at which lead vaporizes.

Stripping varnish with a heat gun has advantages, not the least of which is that the waste flakes off in a dry state, which obviates the need for taping areas off lest dribs and drops of chemical stripper fall on them. But, as is evident in the clop, and RJ’s implicit expressed disdain for heat, it is both slower and potentially more damaging to wood, especially those portions of the hull that will be finished bright.

Burning the wood or dissolving the glue in plywood strakes of a lapstrake hull is the major risk when going the heat gun rout. Indeed, the blackened mahogany tells us that someone must have stripped our 1937 20’ Lyman Runabout’s hull sides with heat. What we found beneath the many, many layers of black paint and primer is a veritable sea of blackened leopard spots.

Fortunately, Eagle’s strakes will be painted. Even more fortunately, the same person did not strip the decks, covering boards, windshield and coamings, for sanding through the singed areas would require major thinning of the planks.

We are standardized on three BAHCO-Sandvik ergonomic scrapers and the wide variety of BAHCO carbide blades. Both are available from JamestownDistributors.com and Amazon.com.

  • BAHCO-Sandvik 650 Premium Ergonomic Carbide Scraper, 1”, 2” and 2.5” – a one-handed scraper
  • BAHCO-Sandvik 650 Premium Ergonomic Carbide Scraper, 1”, 2”, 2.5” – a “big dog” two-handed scraper with a knob just behind the blade.
  • BAHCO-Sandvik Premium Ergonomic Carbide Scraper, 1” – a small detail scraper
  • BAHCO Heavy Duty 2-Inch Replacement Scraper Blade #442
  • BAHCO 449 L-inch Triple-Edge Triangle Scraper Blade

While we do occasionally give competing brands a chance to outperform it, nothing we’ve tried holds a candle to Jamestown Distributors’ Circa 1850 Heavy Body Paint and Varnish Remover. Period., at least during our nine months of winter when cold temperatures, snow and ice make stripping hulls outdoors with one of the spray-on strippers at best impractical.

Finally, after trying a dozen or so brands, we have settled on New Star Foodservice 54460 Extra Large Stainless Steel Sponges Scrubbers sold by Amazon.com. (https://www.amazon.com/gp/product/B00…)

RJ takes you through the steps needed to arrive at you clean wood goal.

  • Strip the surface material – varnish or paint – using the chemical stripper of your choice.
  • The Chemical Rout
    • Apply the stripper three times, allowing about 20 minutes working time between each of the coats.
    • Scrape with the wood grain using the two-hand scraper and long strokes.
    • Apply another coat of scraper. Let it work for five minutes or so and repeat the long-stroke, two-handed scraping.
  • Apply the stripper again, wait a minute or so, reach for the stainless-steel sponge scrubber and scrub the surface briskly with the grain until the wood is dry.

Avoiding produce long, deep scratches that result if excessive down pressure is applied. While we continue using the same sponge for job after job after job, reaching for a new one, which will be less aggressive on the wood, might be a good “first-time-through” strategy.

Congratulations! You have reached the clean-wood goal and are ready to bleach!

1937 Lyman Cruisette – Rot Unveiled When Varnish Stripped

1967 lyman cruisette rot under varnish

We truly believed we’d found any and all rot existing on Eagle’s hull, but forgot a major reality. Some sort of stained paste filler and varnish, which is what was used on parts of the foredeck and elsewhere on her hull, can hide all manner of deterioration.

In the Eagle’s case it hid rotted foredeck planks on both port and starboard along the seam between the covering boards and deck planks.

We now face releasing the coamings and dashboard if we wish to address these issues, and the required plank replacement properly.

This rot strengthens our resolve that the deck, coaming, windshield and covering boards be stripped to bare wood.

Additionally, as I strip the foredeck using a DeWalt LCD heat gun (https://www.amazon.com/DEWALT-D26960-…), Sandvik Ergonomic scraper and BAHCO blade (https://www.jamestowndistributors.com…) . I have been exposing more of that paste filler under what appears to be precious few coats of varnish.

As I will amplify in our next update, just releasing varnish, whether chemically or using a heat gun, is only the first step in cleaning the wood. As is clear in the clip, scraping away the varnish leaves a residual-stain-mottled surface behind.

All of that stain must be scrubbed and bled out of the wood using Circa 1850 Heavy Bodied Paint & Varnish Remover (https://www.jamestowndistributors.com…), stainless steel pot scrubbers and lots of elbow grease. How clean is clean? You will know when you get there.

I will go into these last topics in greater depth later today.

1954 Penn Yan Captivator Aristocrat: How to replace the Transom

1954 penn yan captivator replace transom

We are almost there. Beginning with two raw boards yesterday morning, Joe and RJ have fabricated all the parts to Captivator’s new transom.

We allowed the glue in the tongue-and groove joint between the two transom planks to cure for 24 hours before removing the clamps.

Today they fabricated the interior transom frame using oak for the bottom bow and two side frames and Honduran mahogany for the center frame.

The individual oak components and the transom blank were cut to shape using the old material as patterns.

What cannot be patterned simply are the bevels and continuously-changing radii of the transom blank’s ends and the oak framing that runs up the hull sides. Sanding in with a belt sander is both tedious and exacting, and requires continual test fitting.

With the individual components fitting well, RJ and Joe assembled the new transom temporarily before final fitting ensues.

Once we have an excellent fit, the components will be released, final sanded, bleached, stained with Jel’d stain and sealed with three coats of CPES.

Sometime early next week Captivator’s new transom will be in place, bedded in 3M5200.

1954 Penn Yan Captivator Aristocrat: How to Fabricate a new Transom

1954 penn yan captivator fabricating transom

Happily for her and her owner, we have been saving the last Pattern Grade Honduran mahogany plank from an order I made ten years ago for just the right application. It had been held in inventory for over two decade at the many small furniture shops that fell victim to the Great Recession of 2008-2009. The planks had been sawed, stickered and begun air drying a decade or so when purchased by the shop’s owner.

While our 1954 Penn Yan Captivator Aristocrat is losing her original transom, her “new” one will be fabricated using wood that is almost as old as she is.

It took a bit less than a nanosecond for us to agree that we will use that plank for Captivator’s transom planks and center frame member.

The original transom planks were glued up employing a splined joint – grooves cut in the two mating surfaces are joined by a thin strip of mahogany, aka the spline. However, we will mate the two boards using a tongue and groove joint.

Why? Joe, who spent years managing a commercial precision woodworking – custom window and door design and fabrication, has experience with, and has tested, both mating systems. His experience argues for the tongue-and-groove rather than the splined joint as stronger and better able to survive flexing and expansion/contraction cycles.

Joe cut the tongue in one and groove in the other soon-to-be transom plank using a table saw. Two pieces of scrap from the same planks were used for setup.

Finally, once they had been run through the jointer, Joe and RJ will set up a half-dozen pipe clamps, with three spaced along each side of the plank. Wax paper will be laid beneath the joint and copious amounts of Titebond III Ultimate Wood Glue will be applied to all surfaces. (https://www.amazon.com/Franklin-Titeb…)

Even though Titebond stipulates an 8-hour dry time, we will wait a full 24 hours before breaking the clamps down.

We will focus on her bottom once we’ve installed her new transom and its associated framing.

Happily, our worst fears, that we’d discover extensive garboard rot beneath the keel, did not happen. Despite the open seam along both sides of the keel-garboard joint, there was nothing but a tiny bit of rot way forward where the keel and stem join.

That said, once we have tightened fasteners where needed, sanded the bottom fair and applied three full coats of Clear Penetrating Epoxy Sealer to both the keel and bottom planking, keel installation will be upon us.

We will treat the keel installation exactly as we do when installing external bottom planks in a True 5200 Bottom. Fifty-Two-Hundred will be troweled into the entire area beneath the keel, and to an about 1/8″ thickness. Then, as we sink the fasteners from the inside out,, we will be certain that the entirety of the mating surfaces are entombed in 5200.

We will clean the squeeze-out with Interlux Brushing Liquid 333 and then wipe the seam down with acetone, which will accelerated the curing process.

Then the real fun begins as all the seams between Striptite planks must be caulked using Interlux Seam Compound For Underwater Applications.

Why not 5200? Once cured it will not compress. Any drying and shrinking of the planks either breaks the adhesion, as we saw with this bottom initially. Any soaking-up and subsequent plank expansion threatens crushing the planks.

1954 Penn Yan Captivator Aristocrat Releasing the Transom (pt 2)

1954 penn yan captivator releasing transom

Part II continues chronicling our woeful discoveries.

Not only were our worst fears, implicitly expressed in Part I of this pair of clips, confirmed, I was blown away by the fact that the bottom “bow,” pronounced “beau,” were not only severely rotted, they were also quite wet. Honest! She has not been in the water since last fall, has been in dry cold storage since then and, yet, the bottom bow pegged our moisture meter and more.

As soon as we release the bottom transom plank and the framing, RJ will begin fabricating a new one. Replacing the transom’s interior framing was not in our scope of work, as we hoped against hope that the dark wood we observed during our initial observations might “only” be a bit of surface rot.

Not! This situation adds complexity to our project elsewhere as well. The two transom frames running behind the topsides are secured by copper nails driven from outside through the topside planking and into these frames.

Sadly the forward of the two courses of fasteners run through topside planking that is finished bright. We will do our best, but now fear that stripping and finishing the topsides anew has been added to the SOW.

RJ will fabricate and then he and I will temporarily install the bottom plank, the one we have just released, first, which will ensure the hull retains its proper shape.

1954 Penn Yan Captivator Aristocrat: How to Release the Transom

1954 penn yan captivator release transom

With the keel, outer stem and splash rails released, and having cleaned all of the 5200-like material out of the bottom plank seams, our attention turns to the transom.

The transom is two planks that have been fixed to both the topside and bottom planking, but also to a series of frames. Individual frames run along the bottom, sitting on the bottom planks, across the top and down the sides of the transom. A pair of inverted “V” frames stiffen the transom’s center.

Upon initial inspection RJ and I were troubled by what appeared to be very poorly conceived and executed repairs to the center and port frames. The “Dutchman” attempted at the bottom of the pair of center frames not only created a powerful water trap, the rot growing there propagated and destroyed the bottom bow – “beau”.

Part II continues chronicling our woeful discoveries.

1954 Penn Yan Captivator Aristocrat Post Stripping Findings

1954 penn yan captivator stripped hull

Yesterday we stripped her transom, flipped her, released her splash rails and stripped her bottom. Happily the splash rails are in excellent condition. They only want to be stripped, have some minor “bodywork” executed and refinished.

Today we released the keel and began releasing the keelson and the transom framing.

While the keel is in excellent shape, both in terms of being straight and sound, it has been off the boat at least once and sealant was given short shrift when it was last installed. As a result there is some rot, not so much that it cannot be repaired, on the garboards where they lie beneath the keel and the keelson.

Her owner informs me that the keel was not released by the shop that worked on her in 2007-08, but the myriad of plugged mounting holes tell us that it was released sometime prior to that work being done.

The paucity of sealant means that water will find its way into the bilge.

It will also sit in the bilge. That there is not more rot is testimony to the care given her by her current owner.

The rot we did find beneath the keel is far forward, and at the joint between the keel and the lower portion of the stem. That curved section runs from its joint with the keel up to the splash rails.

Once we have the keelson and garboards out of the hull, everything, garboards, keelson and keel, will be cleaned to absolutely bare wood. Once the components have been sealed and receive three coats of Clear Penetrating Epoxy Sealer, they will be set aside.

Next comes the most fun. The failed transom, which we must replace, must be released from the hull. That it is secured with many, many copper nails, and not wood screws, makes this task particularly challenging, but doable using a FEIN MultiMaster and the thinnest, narrowest blade we have. (That they are copper, and therefore quite soft, should translate into the MultiMaster zipping right through the nails leaving a clean surface behind.

1954 Penn Yan Captivator Aristocrat Flipped

1954 penn yan captivator flipped

We’ve flipped all sorts of boats, big wide ones, long deep ones and now our 1954 Penn Yann Captivator Aristocrat.

Forget the winch. No grunting needed. Her size, narrow beam and cylinder-like cross-sectional shape made flipping her hardly different from rolling a 5-foot diameter pipe.

Now that her bottom is fully exposed, I must say that I was surprised just how little paint is on it. We will know better once we begun stripping, but my guess is a couple of coats of red lead primer followed by about as many of some sort of gray paint.

The garboard-keel seams on port and starboard, while open, appear to be less so that we thought they were while lying on our backs looking up at the hull.

Once we have released both splash rails and masked her topsides, we will reach for the Circa 1850 Heavy Body Paint and Varnish Remover and strip the bottom down to raw wood.

We will surely share what we find and how we will attack the issues we unearth then.

How to Install Bottom Battens in a True 5200 Bottom – 1938 19′ Chris-Craft Custom Runabout

1938 chris craft runabout bottom battens

As is typical of all Chris-Craft utilities and runabouts, this 1938 19’ Chris-Craft Custom Runabout, Flyin’ By’s hull is comprised of a series of heavy frames to which the bottom is fastened. A series of battens run athwart between the frames, thereby adding substantial stiffness to the bottom.

Simply put installing battens is a thankless, two-person challenge. Here are the steps for installing one batten at a time, followed by filling the countersinks, fairing the bottom, sealing, priming and applying bottom paint. The process is described for one batten, one that will be repeated for all of them:

Installing the Battens.

  • From the inside, drill two pilot holes towards the ends of the batten. • Using a straightedge and pencil, scribe a line between the pair of holes.
  • Drill holes along the line, about 1.5 inches apart using a countersink pilot drill.
  • Dry fit the batten and, while the guy underneath presses it in place, drill two holes from the outside in through two of the countersinks.
  • Sink screws through those two holes. We use #6 x 1 or x 1-1/4, depending on the thickness of the inner plywood skin plus the exterior planks.
  • Stand the remaining screws through the remaining holes and drive them home.
  • Release all of those screws for now.
  • Butter the batten’s bottom face about 1/8” thick with 3M 5200 – mahogany.
  • Hand it to the guy beneath the boat, who presses it in place.
  • Starting with the two end screws, and remembering to stand screws in all of the holes, drive all of them in place. (Standing the screws in the holes first ensures that fountains – volcanoes? – of 5200 do not squirt though the other screw holes as you work along the batten.)
  • Repeat for all battens on both bottom faces. Flyin’ By has twenty of them per face.

Filling Countersinks and Fairing the Bottom.

Filling countersinks and fairing the bottom is next. We use 3M Premium Marine Filler, available from Jamestown and elsewhere, to fill and fair the countersinks.

Three applications are required. We sand using 80 grit and one of our Festool random orbit sanders after the first coat, just to knock down ridges and what I call overspread.

Once the last application has cured – about 4 – 6 hours – we sand the entire bottom fair using 80 grit on our pneumatic longboard sanders. Declivities may show themselves at this stage, which requires interrupting the sanding as Premium Filler is applied to them. Sealing, Priming and Bottom Paint.

Once the bottom is fair, apply three coats of Smith’s Clear Penetrating Epoxy Sealer. Danenberg recommends applying the second coat immediately after the first, so we apply the CPES to one entire face and then return to where we began and apply a second coat.

I know there are other penetrating sealers available, and we’ve tested most of them. Let me just say that we use Smith’s CPES, which is available at good prices from Star Distributing in West Mystic, CT: http://www.star-distributing.com/smit….)

Our go-to primer is Interlux InterProtect 2000E Two-Part Barrier Coat Epoxy Primer because it works

From Jamestown:

Interlux’s Micro-Plate formula creates an effective barrier against water permeation. 2000E may be used above and below the waterline as a universal primer for all surfaces. It is also an excellent primer for all metals and can be used as part of a no sand system.

From Interlux:

  • Two-part epoxy water barrier with Micro-Plates
  • Up to two weeks is allowed between coats of 2000E
  • Now available in two colors, Gray and White
  • Fast drying, easy application
  • Sag resistance to insure the elimination of sags and runs during application

Technically, InterProtect Micro-Plates provide millions of overlapping microscopic plates that create a barrier similar to shingles on a roof. These overlapping Micro-Plates eliminate any direct path for water migration and also improve the sag resistance of the epoxy making application easier.

We will have a gallon each of gray and white 2000E on hand for Flyin’ By’s bottom and chine plank – boot stripe included. Once we’ve applied five thin coats, we will have created an impenetrable barrier against water permeation.

Since Flyin’ By will be dry sailed by her new owners, we will apply three coats of Pettit Old Salem Copper Bronze Hard Racing Enamel, at which point she will sport a True 5200 Bottom.

Finally, she was in show ready condition, with over 20 coats of varnish having been applied and buffed when the moment to flip her arrives. No matter how careful any of us is, and no matter how many pads we placed strategically, Flyin’ By is heavy, and her hull shape presents long sweeping curves. And with three of us working around, under and even atop her, bumps and bangs are all but inevitable.

That said her varnish is scuffed in several places, so we will sand the entire hull flat anew and apply three or so coats of Interlux Perfection Plus Two-Part Varnish to her, and let it clear before she returns to storage.