Core Sound 15 -- The Decision and Some General Questions

[Hirilonde]

If epoxy isn't totally water proof, and I not so sure it isn't, then a well coated plywood boat is the next best thing.  I have had my Spindrift in the water for weeks with no absorption.

[Ken_Potts]

   I've read that epoxy is not completely waterproof but my boat usually sits on a trailer for days then sits it the water for 6 hours.  There's plenty of time for whatever water penetrates a little ways into the epoxy to migrate back out between outings.  Even If I leave the boat in the water for three days on the occasional trip the boat still spends more time on the trailer than on the water.

   The way I made the drain for the main mast tube I've got a good thick buildup of epoxy so if the water manages to get through that most of the rest of the hull will already have rotted.  On the other hand if I hadn't made a drain for that nearly vertical mast tube it would retain any condensation until it evaporated or penetrated the epoxy.  The mast tube is inside the forepeak so there's a temperature difference between the inside and the outside of the tube whenever the ambient temperature is changing (I'm in a humid environment).   That means there will be condensation on the inside of the mast tube when the ambient temps are increasing and if there's nowhere for that water to go it will collect at the bottom of the tube and eventually penetrate the epoxy.

   I think the usual concern over limiting through-hulls is more applicable on a blue water boat where the failure of a thru hull will cause an immediate problem with water entering the bilge.  I don't think it's usually a concern on a trailer sailor.  So if you're crossing the atlantic in your CS17 and you find the mast drain is leaking into the forepeak you should definitely move as much weight as possible to the lazarrette and apply a duct tape patch but if you're not going to cross oceans and you omit the main mast drain make sure you set up a bilge pump to drain the tube when the boat is on the trailer  ;D

   I've had a little bit of a problem with my main mast tube changing size because of moisture trapped in the forepeak but I'm finding that it is not a problem as long as I leave the hatch open while the boat is in its covered storage area.  I can't say for sure whether the problem was caused by moisture migrating through the epoxy or my sloppy workmanship leaving crevices in the epoxy coating but I will say the problem took a year to develop and once I started leaving the hatch open while the boat was stored it took another 6 months to rectify itself (everything's good now).  In short - My minor problem was not caused by moisture at the through hull - It was caused by moisture in the forepeak due to temperature changes in a humid place (as best as I can figure).

   The mast tube drain is a good thing.

[PAR]

The amount of moisture getting through an epoxy membrane is measurable, but not something you're going to see in 6 hours, nor 6 days, nor 6 weeks. Yes, moisture vapor will pass through, but after say 30 days continuous submersion, you might have a whole drop, which has been absorbed across the huge scale of all the exposed pieces, so you'd still not see it (it's in the wood fibers).

[Tom Lathrop]

Hey guys, there is a molehill in danger of becoming a mountain here.  Many of the materials we use are not totally vapor proof, as well as epoxy.  For instance, most of us buy milk in polyethylene jugs.  Polyethylene is not impervious to transmission of moisture vapor.  Notice that it is illegal to store or transport gasoline in these jugs as well as illegal to use one of the red poly fuel tanks in a closed space.  Ever notice that a carbonized soft drink will go flat after a time in plastic bottles?  This is why foodstuffs like potato chips and coffee are marketed in metalized plastic bags.  No plastic is totally impermeable, so an electro-deposited metal film is used to maintain freshness in chips and vacuum in coffee.

For us and the way we use boats, THERE IS ABSOLUTELY NO REASON TO BE CONCERNED ABOUT WATER TRANSMITTING THROUGH A WELL APPLIED EPOXY COATING. Epoxy is a much more impervious material than polyester and polyester boats sit at every dock in every marina in the world for decades.  Yes, moisture does get in.  Osmotic blisters are the bane of these boats and the strength of poly/fiberglass is decreased up to 50% by this moisture, but these boats just keep on doing what they were built to do, albeit with some exceptions.

I have done major repairs or observed plywood boats where the builder just used a slap and dash of epoxy on the interior where water was allowed to collect.  The result in one trimaran was rot spores covering much of the interior surfaces of the amas.  Not falling apart but I would think that the boat is near to being in the dump state by now.  Note that this water did not enter through the hull but through inspection hatches that did not seal well, which is true of most of them.

Its just good practice to store your wood boat under cover with adequate ventilation and leave all hatches and ports open so that any moisture that may have found its way in, can evaporate.  If you don't have hard cover storage, tarps are cheap.  None of the cheaper tarps are much good beyond one season.  Here is one I bought for Lapwing that seems to be great and looks like it will last for many years.  I got the 8 ounce 10x20 size for $30 which I consider cheap insurance.

http://www.tarps.com/white.htm

This is a good time to put to rest the concern about "water getting in and not being able to get back out" through the epoxy sheath and causing rot in the interior. This is an often expressed belief of many who should know better.  For rot to thrive, there must be moisture, oxygen, and food (wood).  Higher temperature helps but, no oxygen, no rot.  Those of us who have been using epoxy almost since its inception, have our own evidence and don't believe a word of it.  This is often espoused by traditional boat folk who happily go about with their boat hull completely saturated with water all the time.  Go figure. ???

[Designer]

I could not have said what Tom said any better.

In my opinion the marriage of plywood and epoxy makes it the wonder material. There is no other material that comes close to stiffness to weight to cost to user friendliness.

The only other comment I want to make about epoxy as a vapor barrier is that thicker is always better. I like the coating to be thick enough that it is shiny slick and not flat and porous. This is usually achieved with three thin coats. A $1.5M plywood sport fisherman will typically have 36 oz. of bidirectional glass on the outside and 18 oz. on the inside.

[Guest LeeH]

Some of you may find this, from Paul Oman, interesting. http://www.epoxyproducts.com/woodseal.html

I think the only usable conclusion is that 2 or more coats is the only way to go. And we knew that already, right?

[PAR]

My usual recommendation is three coats. Two gets it done on 90% of the surfaces, but some areas need just a touch more (particularly fir, pine and spruces), like end grain or particularly soft spots that seem to suck epoxy like a sponge, etc. If it's shinny all over (end grain included), then you're probably good to go.

[Guest Dennis M]

Screwed?

OK, I need some advice. When I glued and screwed the keel batten down some of the screw heads broke when I tried to remove them leaving some screws in. I thought that I would be able to twist them out from the underside with a set of vice grips, but this has not worked well. The longer screws have come out OK, but the shorter ones have broken off. Can these things be sanded/ground down without an angle grinder which I do not have? What do you recommend? Thanks, Dennis

[Hirilonde]

What kind of screws?  (metal used, style, etc.)

If they are stainless or bronze is the part this is still in the boat some where that can be filled/epoxied/glassed over?  It may be just fine to leave them in, but more info and maybe a photo would help people here feel more comfortable offering advice.

[Guest Dennis M]

Dave, they are stainless. I'm not so concerned about leaving them in the hull as I am getting rid of the sharp bits sticking out of the bottom of the hull. If I could get them filed/ground/sanded down without putting a divot in the ply, I think I will be in good shape. Dennis

[PAR]

Unfortunately, you need to grind them (usually not good as the heat will be quite high) or chisel around them then snip them off with something. Repair the area with thickened epoxy. Maybe you can bash them in deeper with a punch or drift pin. Even if it folds over, you should still be able to mash it into the wood deep enough to permit a simple repair over the area. I have a pilotless hole saw made to do just what you'd like, remove the screw, wood and all. Then the hole is plugged with a dowel. Short of this, brute force and some cussing is the typical answer.

[Tom Lathrop]

One of the reasons such screws break is that they are held tightly by the epoxy in the joint.  When it happens to me and there is some part of the screw available, I heat them with a soldering iron to break the epoxy bond and take them out with vice grips. 

[Charlie Jones]

Or take a very narrow wood chisel, chisel away close around the stub until you CAN grab the stub with little vise grips. I use really small ones.

Had to do that just today in a piece of brightwork- fortunately the hardware covered the chiseled out part.

[lbrewer]

I'd use a file.

[Guest Dennis M]

Thanks to all who have given me advice over the past couple of posts. I took Tom's advice and utilized a soldering iron and took the ones out that I could reach. I've got about 4 that broke off and I will chisel around them until I can get at them and then either heat them up and twist them out, or break them off and epoxy over them. That will have to wait until I turn her over. I hope that will be this week.

The c/b has been fitted in the case with good result. The c/b case is almost ready to be installed in the boat. Once I get that done, the boat goes over for the skeg and patching the hull prior to painting it. I spent most of this week fairing the interior of the hull while fiddling with other things and have made much progress, although I am swearing that I will never use S&G construction again. Next time, I'm gonna have someone else build the boat. Who knows, maybe a late June splash is possible.

I'd like to hear folks' opinions about sails. I'm leaning toward the luff sleeve at the moment. Money is tight and an important, though not primary concern. It says somewhere in the plans that one can even use slightly shorter masts.

I'd also appreciate opinions pro and con about glassing the hull.

Dennis

[Ken_Potts]

  I've got luff-sleeve sails and one of the things I really like is that I store the sails rolled up around the masts so rigging is quite a fast operation.  The downside is that it is difficult to reef on the water.  In order to reef I have to roll up the mainsail, roll up the mizzen, re-step the mizzen mast (in the 3rd step) then re-set the mizzen and sail as a cat sloop.  When reffed this way the boats sails very nicely but reefing on the water can be nerve-wracking.  If I had it to do over (which I guess I do) I'd go with sail tracks AND a 3rd step.  More options is better.

Then again, my sleeve luffs do hide all that aluminum mast...

Somebody (I think Rob Blackburn) re-cut his sleeve luff sails so he could reef them.  Graham knows about it and might be able to supply a set of sleeve luff sails that have the zipper reefing option.  Maybe that's the way I'd go if I did it again.  I have vague plans to have the zippers added but I'm to busy having fun with the boat to do anything about it.  If I were doing it over I think I'd probably ask Graham whether sail tracks or zipper reefed luff sleeves were better and then I'd look at Southern Skimmer's sails riding on their tracks and then I'd go with what I thought was best  

  Sleeve luffs = Shorter time rigging, Sail tracks = more reefing options.

[Peter HK]

I've got luff-sleeve sails and one of the things I really like is that I store the sails rolled up around the masts so rigging is quite a fast operation

Ken

I don't think having sail tracks prevents rolling the sail on the mast...probably need a cleat for the halyard on the mast and of course if you opt for battens that slows things a bit (with either track or sleeve).

I really like sails that reef easily.

Cheers

Peter HK

[Hirilonde]

Ken, your sails have no battens?

I have a luff sleeve on my Spindrift sail.  It saved cost for the sail itself and some for the mast (track etc).  It creates a great shape as the sleeve gets pulled into a tear drop shape around the mast when rigged.  I have battens, so wrapping the sail around the mast doesn't work.  It means I have to put the sail on the mast before raising and stepping it.  This isn't a big issue, but can be amusing in a good breeze.  The mast is taken down with the sail on as well, slightly more amusing some times.  My luff sleeve goes from the top of the sail down to the reef point and ends.  So reefing is not an issue.  I had to specify the reefing version to Carla when I ordered it to get this feature vs. a full luff sleeve.  I don't know that this would work on a sprit sail (Spindrift uses conventional boom).  The track would allow raising and stepping masts before raising sails, slightly easier reefing, easier to douse sails completely, easier to temporarily down the sails ready to raise again (for beaching during the day etc) but would add labor and money to the equation.  Like every design consideration it is a collection of compromises.  You need to choose the ones that best suit you.  You can't have it all.

[Tom Lathrop]

On a Spindrift 10, I used a sleeve luff with battens in the sail.  On my BRS Loon, I used unbattened sails with individual loops laced to the mast.  After the original installation, I never took them off again.  As far as I know, Loon has traveled the length and breadth of this country with the sails still rolled up on the masts.  Each rig seemed to be the best for that particular boat.

On Lapwing, after some soul searching, I went with sail tracks and battened sails for the extra area and better sail shape.  While the ease of rigging and storing was far superior on Loon, I had to face the fact that I was reaching the time when I needed the ability to reef the sails while underway.  Since I needed the sail track, it made some sense to go with battens.  I'm not so sure about that now since rigging time has increased dramatically over rolling sails on the masts, which is still possible with tracks and unbattened sails.  I did think up a system of sleeve gaps and zippers to reef a sleeved sail but got lazy and went with a more standard rig.

You will have to decide which system suits your circumstance better.

[wkisting]

We went with battened sails and sail track on our CS20. We're very happy with the decision. It does mean about 20 minutes to rig and de-rig (took 45 minutes the first few times, but now we have it down to a science, and I can rig it solo in under 25 minutes). I think it is well-worth the effort/time, as the sails work wonderfully well and adjust easily. We had a Pocket Cruiser with laced-on sails before this, and I thought that was a bigger hassle--quicker to rig, perhaps, but not as convenient to adjust underway; though perhaps that's not a fair comparison, since that was a gaff rig unlike the CS.

If you want the ultimate in simplicity, there is no question that the rolled on sails will be handier and quicker to rig. If you want the ultimate in performance/adjustability, the slides/battens is the way to go. Either setup will yield a fine boat and I doubt there is a very large performance difference unless sailing aggressively/competitively, so I would let your gut-feeling decide. My gut told me it would take us time to grow into "needing" or being able to take advantage of the benefits of the slides/battens, but now that we've sailed a bit, I'm increasingly glad we chose that setup... each time we go out, I get quicker at rigging, and I learn a little more about how to tweak the controls for better sail shape and performance. [Edit to add: I also think reefing in heavy winds is easier/safer with the sail-track, though that's based solely on my inexperienced understanding of how the sleeve sails would operate/handle, so I may be wrong.]

My two cents.