Transom Delamination Repair

I was just beginning to think that I may be able to get the interior primed this Fall when I discovered yet another project.  The outer skin on the transom has de-laminated from the core due to water ingress.  My suspicion is that winter freeze - thaw cycles did the bulk of the damage.

Introduction

The plan is to start by sounding the hull to identify the region that has delaminated.  As you can see in the above image, I have completed that step.  I'm hoping this is the extent of the damaged area, as the taps went quickly to a dull thud in that area.

I will use my oscillating saw to to cut the interior laminate out, trying to keep things in an easily cut series of rectangles.  The core will be replaced using 1/2" Divinycell foam core, laid up with West System Epoxy.  I will then add a layer of 6 oz. cloth to re-establish the interior laminate.

I began by removing the hardware so I have a clean area to work in.  It is clear that this boat wasn't assembled with sealant anywhere, nor were any of the hardware mounts properly potted with high density filler to avoid compression damage.  The thin skins of this Lightning are great for light weight, but it really mandates proper potting for long-term durability.

The other problem I am seeing is use of plywood for backing blocks, but inadequate sealing of the wood.  To use plywood you need to either seal it in epoxy (preferably) or varnish of some kind.  The upper gudgeon's external block can be salvaged, but my preference is to replace it with a GRP block that's immune to degradation (once painted).  The interior block is rotted, and will need to be ground out and replaced with a new GRP block.  The lower gudgeon's interior mounting block is still in good shape (surprise!).  I plan to sand it, then seal with epoxy and a layer of cloth for protection.

While I'm fussing with the transom, I'm also going to properly pot the transom flap openings in order to better seal them against future water damage.  I would like to cover them with a 6-oz cloth layer as well, but that would require a radius on the openings that may not be feasible.  I need some more time to ponder how that might work.

Stay tuned... More to come!

The Bow is Back

I know I said I wasn't going to do this, but...  I changed my mind...

After speaking with a friend about the bow, he guilted...  I mean, talked... me into making a better long term decision.  While I really didn't want to do this project, I know it's the right thing to do given that this boat will be bashing through Lake Ontario weather on a regular basis.

So, I whipped out my trusted Harbor Freight oscillating tool and made some incisions.  I used a small pry-bar and a hammer to gently tap and pry the top laminate and inner foam out.  It's a good thing my friend talked some sense into me, because the area I thought was about 16" back from the bow turned out to be the entire bow from the tip to the mast compression post.  Much worse than I'd hoped.

The foam was not properly laminated, and had split in many places.  A prior owner had "repaired" this by injecting copious amounts of resin throughout the bow.  They had also laminated nearly 3/16" of resin on the top of it all in some places.  By the time I removed all the foam, I was left with some significant resin pools that had to be removed with an angle grinder and 60 grit disc.  That was no fun inside the tight quarters of that bow.

Eventually I cleaned it all out, removed the dust and took measurements.  I then ordered one large sheet of 1/2" Divinycell foam from Jamestown Distributors, which is enough to do the entire bow if opposing triangles are cut properly.

I did some minor fairing using epoxy thickened with colloidal silica prior to laying up the foam.  I didn't want any significant gaps if it could be avoided.  While colloidal silica is a bear to sand, it's very strong, so makes a good foundation.  With careful use of the spreader I was able to minimize my final sanding efforts.  After a wash down to remove blush final sanding was completed with a 6" RO sander that has nice dust collection ability.  The 60-grit disc should provide plenty of tooth for adhesion to the foam.

Last step was to wet out the bow and foam with neat epoxy and a spreader, then mix up a pretty significant batch of epoxy thickened with colloidal silica.  I actually did this in about 6 batches because it was a hot day and I didn't want it to kick off too early.  Each batch was spread out with a notched spreader for even distribution until the whole area was covered.  I carefully put the new core in place, and pushed down on it to set in place.  The last step was laying some scrap wood battens into place to distribute the load, and then laying some sand bags on top to ensure proper form.

Next steps will be to inject thickened epoxy into any remaining voids between the foam and the existing border, and fair that transition.  Once the transition looks good, I will apply the top laminate of 2 layers of 6oz. fiberglass cloth throughout.  That should conclude the bow core repairs...  Stay tuned!

To Bow Or Not to Bow?

After I cleared all of the leaves and leaking water jugs (buoyancy bags) out of the bow, and gave it a good scrubbing it became quickly apparent to me that someone had done some major fiberglass work in there at some point. I suspect it was replacing core, as little else would really justify the scope of their repair.

The glass work on the prior  repair was very poor.  It was not done with epoxy, or if it was, it sure isn't the epoxy I work with.  The cloth had wrinkles all over, showing either a lack of preparation in properly trimming the patch, or a lack of care in installing it.  These wrinkles trap air, dirt, and become weak points.  With that in mind, I decided that I would hit them with an aggressive grinder to knock down the high spots and open any air pockets in the laminate.  I could then either fill them or lay in some patches depending on the size and depth.  I could then throw a quick and dirty fairing job at it to clean up the worst cases prior to painting.

As I crawled into the bow, prepared to work in a small encapsulated swirling fiberglass dust tornado, I noticed something that made me cringe a bit.  Visible, although subtle, flexing in the bilge.  It's an area about 12 inches wide and 16 inches long, tapering near the bow on the starboard side.  I can flex it about 1/8", which is 1/8" more than I'd like.

Since it's an area that's never visible, it's pretty easy to do some exploratory probing and clean it up without cosmetic impact, so I cut out a section of the bilge, thinking it would come right up.  It did not.  Even after prying on it.  Giving it a bit more thought, I decided that a small area with a narrow span at the bow is probably going to be fine, at least for a year or two.  I ground a quick 2" bevel into the cuts I'd made, filled the bottom of the cut with colloidal silica, and then laid in glass strips to repair the cuts.

With the cuts repaired, I threw a sheet of cloth over the entire area to give it a bit more rigidity, and to help fair the awful surface left by the prior glass work.  It made a big difference, and once painted it will look great.

I have so many projects to do right now that I just don't need to work on anything that's not necessary.  After everything else is done and I've had some sailing time I can make a Spring or Fall project out of laying in new core in the bow bilge.  For now, it's back to the critical path and my tight grip on scope creep.

Blush and Mosquitos

This almost-Fall shorter daylight hours thing is messing with my momentum.  Last night I managed to get all the first layer patches in place, but there were a few places I wanted to build up a little thicker laminate.  Unfortunately, about 75% of the way through cutting out the cloth the mosquitos came out.  And I mean, the whole mosquito air force.  It was brutal. Right about the time I was running out of daylight a dew fell pretty hard on the boat, wetting the cloth, and the surface I need to be clear.  Mother nature put a curfew on by boat works.  Got up early this morning and finished trimming patches, which only took a short time.

The only problem is that since the epoxy cured overnight, it has formed its layer of amine blush which needs to be removed with some warm water and a scrub brush prior to adding layers.  Because the interior of this boat has a mildly textured finish, it doesn't dry out that quickly.  This means that if I have time to get it scrubbed over lunch, it should be ready for lamination this evening.

I would have liked to be done with patching this morning so that I could work on the stringers tonight, but c'est la vie.  Its all about putting one foot in front of the other and making whatever progress can be made.

Stringers and Ants are Out!

It took about four hours, but the stringers are out, and the bilge is ground to a reasonably fair profile.  The harbor freight variable speed multi-tool worked like a charm cutting out the tabs, saving me from using the grinder initially.

Upon cutting out the forward stringer, I was surprised to see a stream of ants come pouring out of the rotted center section of the stringer.  They were not pleased with my renovation efforts.

You have to look close, but the tiny ants are in the picture.  I laid down an ant trap and went about working on other parts of the boat while they died in a sugar-water bliss.

There are a bunch of miscellaneous small repairs I need to do where there were laminate "bubbles" of detachment.  They are now ground out and awaiting new layers of glass.  There is also a crack in the bilge-topsides joint over the aft trailer bunk which will be easy to fill and repair.  The last odd job was grinding out a complete adhesion failure of a stainless plate on the aft bilge.  The installer never roughed the surface, to the fiberglass never adhered.  I've removed the top laminate, and should have no trouble fixing that problem.

By then end of the day, which coincidentally, was about the end of my endurance for hunching over a grinder, I was very pleased with the prep work.  The bilge is ready for me to start laying glass into place.  I'm getting very excited anticipating seeing the cockpit with fresh paint.  Still quite a bit of work to do before that happens though!

Paint Planning

Once I get through the fiberglass repairs, Anyela will need to be painted.  Each area of the boat has unique requirements for either prep, paint, or both.  The repairs will be completed to the underlying laminate first.  Next will come surface priming, and finally, top coating.  But before I can do any painting, I need a plan so I can figure out what to order.

After consulting with Interlux tech support, I'm currently tempted to go with their Perfection 2-part LPU paint for the topcoat.  It's significantly more durable than most of my alternatives.  While more expensive, having to repaint the boat will also be expensive in both money and time.  The 2-part LPU should last about twice as long as a 1-part paint.

As I'll be dealing with some pretty nasty and toxic paint, I will using a respirator with organic cartridges (3M 7178 set), and all painting will be done wearing gloves.

Interior (Bilge and Interior Topsides)

First step is to remove all that wood so I can get to the fiberglass.  Then, clearly, repair any flaws, which is a whole other project in itself.

Anyela's interior currently has a fairly rough texture to it; Not just the texture of open weave fiberglass, but also like 220 grit sandpaper.  While that's great for traction when wet, it's also proven to be an amazing retainer of dirt and muck.  What's more, all areas of the interior which require traction are covered in teak boards.  Additional texture on the fiberglass is just not necessary.

I want to use a filling primer that will tone down the texture a bit, while ending with a smoother finish that will be easy to clean.  Interlux Primekote 2-part primer appears to be the right product.   I don't need to fair the cloth texture out completely, but I don't want it cultivating algae any longer.

The final cockpit color will likely be white.  Not as easy to keep clean, but it's bright and shiny.

Deck

The deck currently has gelcoat texture in the form of lines running parallel to the center line of the boat.  While very functional, it is going to be difficult for me to uniformly retain that pattern after all of the repair areas I need to grind out and fill.  I already see many spots where previous glass work has filled the texture.  Considering that I really want her to look well finished, I think my best bet will be to use a coarse disc on the 6" random orbit sander, and just grind that texture right out to a smooth deck.

As with the interior, I plan to deploy two coats of primer over the newly sanded surface.  The topcoat will be white Perfection, flattened with an Interlux additive to reduce glare, and with Interdeck texture to provide a non-skid surface.

Topsides (External)

The topsides will be prepped with 2 coats of Primekote, then top coated with Navy Blue Interlux Perfection. There is only minor work needed to prep the topsides.  One or two small surface cracks, some crazing, and a lot of area to do basic sanding on.  This, in theory, should be the easiest part of the project.

Bootstripe

I would like to add a boot stripe between the topsides and the waterline.  I'm thinking of something like a rich gold color, but even white would work for me.  I'm still working out order of operations on this part.  Not sure if I should paint all the topsides blue, and then over-coat the blue with boot stripe, or paint the boot stripe directly on the primed hull.  Then again, do I use Perfection for the boot stripe?  More research is needed...

Bottom

Because this boat will be dry-sailed, I don't need anti-fowling.  The general consensus I'm finding on the Internet suggests that Interlux VC Performance Epoxy is the stuff to use on dry-sailed boats.  It is also both a primer and a top-coat, so it saves me some time.

The bottom currently has a paint with adhesion failure which I will need to remove.  An 80-grit disc will make short work of that, after which I'll fill any dings and fair.  80-grit is the recommended surface prep for this paint, so last step will be apply 3 coats of VC Performance Epoxy using a tip and roll method.

The final coat will be wet sanded down to a very fine grit and polished.  Should be extremely durable, and hopefully I'll not have to think about the bottom again for a long time.

All that sounds easy enough, but the bottom is, well...  The bottom.  It's upside down, and very little in life is as tedious as sanding over your head.  I would like to get the boat off its trailer, and flip upside down so I can work on the bottom without pain.  I suspect that will be an interesting operation.

Estimating

Interlux data sheets make estimating fairly simple.  I just need to come up with estimated square feet.  To do this, I divided the boat into triangles and rectangles, which were slightly than the actual area.  Better to be safe than to run short on paint.  For example, the bow is two triangles back-to back, and the sides decks and transom deck are rectangles. 

My rough (and intentionally generous) square footage estimates are as follows:

• Deck: 57 ft2
• Bow: 30 ft2. 
• Side Decks (2):  14 ft2
• Aft Deck: 13 ft2
• Interior (bilge): 100 ft2
• Interior (topsides): 64 ft2
• 32 ft2 / side
• Topsides (exterior): 64 ft2
• 32 ft2 / side
• Bottom:  100 ft2

According to the product data sheets, the following guidelines can be used for coverage:

• Interlux Primekote: 450 ft2 / gallon (brushed)
• Interlux Perfection:  488 ft2 / gallon (brushed)
• Interlux VC Performance Epoxy:  200 ft2 / gallon
• Interlux Intergrip 2398c:  4-6oz per quart / 16-24 oz per gallon.
• Interlux Flattening Agent for 2-Part Finished:  mix 1:1 with finish coat for satin finish.

The resulting painting schedule should be as follows:

• Deck (57 ft2)
• 2 coats white primer (114 ft2)
• 3 coats white Perfection (171 ft2, or  1.5 qts )
• Cut required paint by 50% due to flattening agent:  .75 qts
• Flattening Agent (1:1 mix with Perfection top coat.)
• Assume need for 1:1, or .75 qts
• Interdeck texture additive 4-6 oz / quart.
• Interior Bilge (100 ft2)
• 2 coats white primer (200 ft2)
• 3 coats white Perfection  (300 ft2)
• Interior Topsides (64 ft2)
• 2 coats white primer  (128 ft2)
• 3 coats white Perfection (192 ft2)
• Exterior Topsides, includes Transom (64 ft2)
• 2 coats primer (128 ft2)
• 3 coats navy blue perfection (192 ft2)
• Bottom (100 ft2)
• 3 coats VC Performance Epoxy  (300 ft2)

Which leads to a Bill of Materials as follows:

1. Interlux Primekote Primer (white):  570 ft2 = 1 gallon + 1 quart  (5 qts)
2. Interlux Perfection (White): 663 ft2 = 1 gallon + 1 qts (5 qts)
3. Interlux Perfection (Navy Blue):  192 ft2 = 2 qts.
4. Interlux flattening agent: 1 qt.
5. Interlux Intergrip 2398c Additive:  1 qt.  Not sure how much will be needed until I try.
6. Interlux VC Performance Epoxy: 300 ft2 = 1 gal + 2 qts (6 qts)

I will revise this page after I complete the project to show how much I actually used.

Resources

• Interlux Primekote Data Sheet
• Interlux Perfection Data Sheet
• Interlux VC Performance Epoxy Data Sheet
• Interlux Intergrip 2398c Additive Data Sheet
• Interlux Flattening Agent for 2-Part Finished Data Sheet

Marine Hardware: Dinghys are Yachts Too!

If you maintain a "big boat" properly, you know that most hardware should be proper 316 stainless steel, excepting specific scenarios for avoiding corrosion due to dissimilar metals.  You also (should) know that all hardware penetrating a permeable material (like deck core) should be potted using thickened epoxy.  Hardware bases are also supposed to be sealed to avoid water ingress.  But on dinghys?

If it's cored, or has wood under an active stringer, then I'll buck common convention and cast my vote for properly potting everything that has a permeable core.  Why?  For the same reasons we do it on big boats.

As I was removing the bolts which fix the benches to the stringers I had a heck of a fun time due to the nuts being rusted in place.  That rust has also left stains in certain places on the hull where its had time to weep.  Proper 316 SS hardware would not have rusted in place and gripped the wood in the same way, nor would it have left stains.

A properly potted hole in a cored laminate also provides a compression post which keeps the outer laminate from cracking and admitting water.  I removed many nuts that had been tightened right into the laminate.  This made them not only difficult to remove, but it also damaged the underlying wood by crushing it, allowed water into the cedar core via the cracks, and over time may have allowed sufficient water in to freeze and expand causing failure of the stringer tabs.

Over time that same water which was trapped in the laminate would rot the stringer, or at least the area where the crack occurred, giving the appearance of a loose bolt.  After a few times being tightened, the washer and nut would crack their way right through the fiberglass.

Dinghys are usually not off-shore vehicles, and are not subject to the same loads that a "big boat" deals with.  But unless you plan a short life span for one of these boats, they need the same care to keep them structurally sound, and save a future owner the hassle of structural repairs.