Core Sound 15 -- The Decision and Some General Questions

[Guest Dennis M]

I've made some progress since my last post: The CB trunk has been made up and fitted along with the thwarts. I've cut the c/b blanks and am ready to glue them up. I've cut scarfs in the carlins and am ready to glue those up as well. I decided to utilize round access ports under the aft seats, so I've cut the holes for them and glued and filleted the seat fronts into place. The aft bulkhead has been cut and is ready to be glued and filleted in place. Can you tell I'm waiting for glue? ;D I've also got the bilge stringers cut -- the easiest job so far -- accurate, too! I am wondering how folks have attached these. Did you screw them down from the outer part of the hull and then fill and fair the holes later? - Dennis

[Oyster]

Anyone heard from Dennis? He seems to have dropped off the face of the Earth.

[Guest Dennis M]

Hi, Mike, I'm still around. The winter has been brutal in these parts and so construction came to a grinding halt on Nov 1. I'm getting back into working on the boat slowly.

I've made a bit of progress, however. The side decks have been cut and dry fitted. The foredeck has been cut as well, but I'm having some trouble getting it to lay down. I can't quite figure where the problem is here, but I have not given too much time to it either.

I've cut the CB slot and have glued up the blank for the cb. Getting the cb shaped and checked for fit in the cb is my focus at the moment. I'd like to get the cb case glued in so I can turn the boat over and work on the outside of the hull.

I'm wondering whether to sheathe the hull in 6oz glass cloth. I'd like to hear what folks have done. I used Okoume ply, and since I just fixed a puncture in another boat made of the same material, I am concerned that the hull will not be sufficiently protected if it is not glassed.

Regards,

Dennis

[Guest Dennis M]

Hi, Graham,

I have the c/b cut, shaped and fitted in the case. All looks well and works well except the fact that there are about 3/4" board showing (leading edge) below the case for about 5 inches near the aft end of the board. Once the case is installed, I figure about 3/8" of this will be exposed. I can't tell from the drawings if this is the "right fit" or not. All the dimensions of the board (l&w) are as per plans. Is this acceptable? Thanks, Dennis.

[Designer]

Dennis,

I just laid the centerboard in the trunk using the pivot center as a reference point and I find plenty of clearance between the leading edge of the board and the lower edge of the trunk.

You need to recheck your measurements. It is not a big deal as your keel is still below the board, I would be inclined to trim the board down but I would wait until the the trunk is fitted in the boat.

[Guest Dennis M]

Thank you, Graham.

[Guest Dennis M]

Installing a Bailer --

What kind of goop do folks use as a bedding compound for the bailer? ~Dennis

[John Burritt]

One that works is 5200

[PeterP]

I basically agree with John though I switched to silicone for a lot of stuff. 5200 is a tough customer to deal with once it sets up. Also, I got tired of throwing away tubes that were 80% full that somehow cured while I was waiting for the next application to come up. Gets expensive that. Silicone will not take paint while 5200 will. And 5200 is a whole lot stronger. Your bailer will have six bolts through it so you do not need the strength and if you leave it open and tear it up while pulling the boat off the trailer you may be glad to be able to yank it off for repairs. PeterP

[Ken_Potts]

Besides the 5200 "adhesive sealant" there's a 4x00 "Sealant" something (I don't remember the exact number).  Using that stuff you'd still probably be able to dive under the boat and remove the damaged bailer to repair it even if it was a bit chilly that day - I wake up in a cold sweat sometimes thinking about sliding the boat off the trailer with my bailer open.  So far I've been lucky - I've winched the boat partway onto the trailer with the centerboard down and the downhaul tight ("Huh, why is my boat falling over?") but I haven't made the bailer mistake yet (but I will, I know I will).

[Guest Dennis M]

Thank you, Gentlemen. I appreciate the replies.

On another topic, I am at the stage where I need to decide whether to glass the hull or not and determine the type of paint I will use. I've heard that the system 3 paint product is quite good, but how does it hold up to the abuse of trailering and beaching? I'd also like to know what folks experiences are with regard to touching up/maintaining this type of paint. I've used Brightsides in the past and while I like its toughness, touching up is rather a pain due to its hardness.

Also, what do folks do to remove water from the fwd mast step, or is this a problem? I'm sure that ya'all are Herculean types who just turn the boat over and give it a shake. Thanks, Dennis.

[Ken_Potts]

The plans show a drain tube built into the forward mast step.  I can't remember which page...

[Hirilonde]

My thoughts on sealants:

Silicone is pure evil.  I will never use it again.  Not only does nothing stick to it, but it absorbs into virtually everything contaminating it from ever holding paint, glue or any other sealant/bedding in the future.  It was the best there was 20 years ago.  There are so many better products now for every application.

3M 5200 is for stuff you know you will never ever want to take apart again.  It is not needed when mechanical fastening is used.  It really is seldom needed.  When used on hardware it can tear fiberglass apart when the hardware is removed.  I don't need that kind of destruction when it comes time to remove something, especially when I didn't need that kind of adhesion in the first place.

Polysulfides (3M 101 and Boatlife Lifecaulk) are both mildly adhesive, very pliable for many years, but some what of a mess to clean up after application.  They are paintable and relatively easy to clean up after removing the bedded item.  The white product yellows in time.

Sikaflex 291-LOT is a polyurethane like 5200 and 4200 but with less than half the adhesive strength of 5200.  It applies and cleans up very nicely.  It does not yellow.  It is my favorite adhesive bedding.  It is a little harder to tear apart later than I wish it was, but no where near as bad as 5200.

Dolphinite aka boatyard bedding is still a viable bedding material after many many years.  It is today's version of what was used over 100 years ago.  It has little adhesive properties, but works great for bedding stuff.  It stays pliable for many years and comes apart later with little effort and no damage to the bedded surface.

I use all of the last 3 often, 5200 seldom, and silicone never.  Each bedding situation has its own requirements.  I suggest you define those requirements, then choose the material that best meets them.  There is no best material for all applications.

Jamestown Distributors has a good description of many material that allows you to compare them.  This allows you to choose the most suitable for your application.

[Ken_Potts]

Silicone is pure evil.  I will never use it again.  Not only does nothing stick to it, but it absorbs into virtually everything contaminating it from ever holding paint...

Just as an aside - If you walk into a car factory with a tube of silicone you will probably never be heard from again.

[PAR]

I bent a piece of 3/4" PVC pipe to drain the mast tube, from the bottom of the mast step, back to the cockpit, rater then over the side at the bow. This was a client request as he sails in salt water and wanted a positive way of removing all the water and didn't like the idea of a through hull at the bow.

Silicone is only good for bedding glass or acrylic windows into their tracks or channels. It has little other use on a boat.

Dolfinite has no adhesive qualities at all. I've removed parts bedded in this oil base goo, that haven't been moved in 50 years and the stuff is still pliable. It requires fairly tight fitting joints.

I use polysulfide under the LWL exclusively. Polyurethanes will release from wet wood.

Above the LWL polyurethane works well, though many can yellow with UV exposure, some are formulated to resist this better. Both are paintable and can be sanded when fully cured.

System Three's WR-LPU's are very good, though not as durable or have as much gloss retention as solvent based LPU's. They are easy to apply, once you understand how they work (they need lots of humidity to keep a wet edge). They dry very quickly and are the second hardest paint you can use. Their clear can used be as a substitute for varnish, but the gloss thing is an issue for a lot of folks. It can be buffed to a pretty good gloss, but it's never going to be the blinding shine of a solvent based LPU.

I've used them, figured out how to get good results, then switched back to solvent based products (Sterling and Awlgrip) which are harder to apply, but more durable, higher gloss, lay flatter if tipped off and a lot more colors to choose from (you can mix WR-LPU's with each other for custom colors)

[Tom Lathrop]

This is the method I devised to drain water from the mainmast tube.  The first photo shows the epoxy bushed hole with a 1/4" ID plastic tube sticking out.  The tube extends all the way into a hole in the side of the tube at the bottom.The second photo shows this tube bedded over with epoxy and glass.  After the epoxy sets, pull the plastic tube out, but don't wait too long or it may be difficult to remove.  Leaves a clear path of about 3/8" for water to drain.  Many of Graham's builders have adopted this method.  Never have to be concerned with getting water out of the tube again.

[Ken_Potts]

I did what Tom did but I used a straw from McDonald's because they've got a big O.D. and there was one sitting there looking at me when I was looking for a tube...

[Peter HK]

Also, what do folks do to remove water from the fwd mast step

I see you have had a number of replies.

What I did was make a fibreglass tube and drain it at an angle downwards and aft through the bottom of the mast step.

See photos

Peter HK

[Guest Dennis M]

Thanks to all who replied to my query. Don't the through hull fittings (bailer and mast cylinder drain), even with epoxy, make the hull more vulnerable to water damage and rot? It is my understanding that epoxy is not completely waterproof. ~Dennis

[Peter HK]

Hi Dennis

You are right that epoxy is not totally waterproof and doesn't stop water penetrating into wood- it does slow the process dramatically however.

These boats are intended to sit on a trailer between sailing days- in this situation the issue is letting any water out after sailing so that it doesn't sit there and cause rot. The mast drain and bailer are good at this.

Even if you are storing outside under a tarp where some rain could enter the fact that they drain the water away will protect the hull.

Cheers

Peter HK