Core Sound 20 Hull #102

[Designer]

Butt blocks are in lieu of scarfs on the cockpit seats and decks. I prefer them in this case over scarfs because they are quick to do and you get a neater glue line if you want to finish it bright. The greatest load will be from someones big foot which puts the butt block under tension and is probably stronger than a scarf by having more material further away from the neutral axis. You can add a few small beams if you like.

[Gordy Hill]

At a weight of two hundred and forty twelve I wish I'd used 9mm on the seats. The little extra weight would have been worth it. Also, on my CS17 I found the seats fine for sailing, but a bit too narrow for those times in light wind when I'd like to face forward, lean back and put my feet up on the seat. By the way, that position is great when you gently cruise past a Sea Pearl.

Gordy

[Brent]

Lets see if I can post a picture...

[wkisting]

Would adding a few extra horizontal 3/4" x 1" stringers suffice to strengthen the seats, or should I add partial bulkheads of 1/4" ply that extend all the way to the floor? (In the latter case, I'd cut a large hole in the center of these bulkheads, of course, to still allow airflow throughout the seat chamber and to permit passing through of long items that I want to stow inside the seats.

I'm wondering if with the seat flex, the horizontal stringers might simply snap (?) instead of actually increasing support.

[Peter HK]

I used ply and taped it where I thought the seats could use it- light, stiff & strong.

Peter HK

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[JeffM]

When I asked Graham about seat reinforcement, he commented that a longitudinal stringer down the center of each seat would help tie the (transverse) grain together, which a transverse stringer wouldn't do.  I went with a few extra transverse stringers anyway, in places where there weren't already hatch framing or whatnot close by.  I've never found my seats to be underbuilt, and I'm 210 with a regular crew of two active boys.

[wkisting]

Regarding paint... do any of you recommend a primer? It sounds as though the Interlux VC Performance paint I'd like to use can be applied directly to bare fiberglass, but I'm wondering if using a high build primer first would yield a better finish? Thoughts? I'm planning to use the same paint for the entire boat, unless there's any good reason not to use bottom paint on interior surfaces....

Also, where is the ideal place to locate cleats, etc.? I'm planning to equip my boat with the staysail eventually, and I know I read somewhere about where the cleats needed to be positioned for the running backstay, but I can't find the thread. Ray mentioned using U-bolts instead of cleats at the stern... Is it better to mount them vertically on the transom, or horizontally on deck? If the latter, I would think they could be used to attach a yoke for the mizzen sheet to pass through, and could also be used to fasten dock fenders, no?

Got the seat faces cut out today... will glue them in tomorrow (waiting for the butt blocks to cure). Also put on the transom stiffner. Things will start to pick up after this coming week because the following week is our Spring Break down here in Augusta, GA (timed to coincide with the Master's Tournament). That means a full week of uninterrupted building! So I've got to get ordering supplies now.

[Norman Colter]

A full week Wes, I'm jealous. FWIW I primed with system three WR. Like it very much.

I think Ray suggested bow eyes, not u-bolts. They're not the same thing.

One of the fastening points for the staysail is the forward top of the mizzen mast.

Have fun,  Norm

[Charlie Jones]

I think Ray suggested bow eyes, not u-bolts. They're not the same thing.

They are most definitely NOT the same thing. Bow eyes would be the thing I'd use, NOT U-bolts.

[wkisting]

Thanks guys... yes, I meant "bow eyes" not "U bolts," though some of the bow eyes essentially are U bolts with an extra flange and a second set of nuts (probably nicer stainless, too).

I'm really confused about the paint issue... Can I paint the entire boat with Interlux VC Performance (which is a below-waterline paint), or is there a reason to switch to a topsides paint for topsides and interior surfaces? And how does one choose a primer?

Looking at old posts about paint, I can't tell if it's fine to use bottom paint on topsides, though I see that some folks use topsides on the bottom of trailered boats.

[wkisting]

Talked with Ray on the phone last night for an hour or so... what a wealth of knowledge! He's convinced me to give the Systems 3 LPU paint a try. The decision was confirmed today when Interlux tech support wrote me back about my paint inquiry and warned that spraying Perfection topsides paint can be very dangerous without a full-body suit and high-quality breathing apparatus due to the atomization of the chemicals. Sounds like the [water-reducible] LPU is much safer to work with in that regard, and Ray raved about the ease of use (quick dry, lack of odor, etc.). I like safe and easy!

I still think I might try spray-application, though Ray recommended brush application for the ease of touching-up later and the quality of the results. But my roofer has offered to let me use his HVLP sprayer free of charge, and it will probably go on oh-so-much quicker in lighter, more even coats. (I've seen folks spray on paint before... I envied them greatly.)

Anyway, thought anyone who follows this thread might be interested in how/why I made the decision. I'll be posting a write-up of my experience with the paint on the website (www.roguepaddler.com/coresound20.htm) sometime in the next few months.

[Hirilonde]

  Sounds like the LPU is much safer to work with in that regard, and Ray raved about the ease of use (quick dry, lack of odor, etc.). 

Taken in context, I think I know what you meant, but I couldn't disregard your statement. Your sentence needs serious modification.  Water born LPUs are safer.  LPUs like Awlgrip and Alexaseal which are not water born are among the most dangerous paints available.  Nothing short of supplied air is acceptable protection when using them, especially when spraying.  There is no known respirator cartridge that will filter out the isocyanates.  I would bet this is part of why Ray likes the System 3 product in particular.

[wkisting]

Hirlonde, yes, thanks for the clarification... I didn't mean all LPUs... I meant only the water-reducible LPU by Systems 3. The idea of a relatively safe, low-odor, easy clean-up paint is very appealing to me. I have no experience with other marine paints, but I've gelcoated a kayak hull before... gelcoat is just about the most noxious stuff I ever care to be around. The fumes are so strong they will literally make your eyes burn within seconds of mixing up the gelcoat, and if you take off your respirator for even a few seconds, the fumes (even while working outdoors), can overpower you and leave you lightheaded after just two or three breaths. I can hardly imagine how much worse the problem would be if you were to atomize those chemicals by spraying.... which is probably why the Interlux people emphatically warned me about the dangers of spraying Perfection topsides without some serious respiratory gear.

[inboil]

I found the WR LPU a little finicky to apply with hvlp( not the gravy like all water based laquers that I have used.)It dries faster than January snot in Louieston (that's pretty dadgum fast mistah), which will lead to a pebbly finish. The primer sprays pretty well, some orange peel which you sand out any way. You need a fairly fine tip and I had to reduce it considerably more than was recomended. Their sugestion to use an extra length of hose dunked in a bucket of ice would probably help( turbine produces hot air which dries paint even faster).I couldn't make my cheapskate alter ego buy that hose so I'm only guessing here.

        That said; the lack of toxicity and the hardness/durability of the finish will make WR LPU my choice again next time. Maybe I can hide the fancy-pants spray gun and try it Ray's hand-method. But then  the gun might be lost in the ether along with some other "hidden" tools.

[inboil]

oops- that's supposed to be january snot FREEZES in Louieston

[Dale Niemann]

Wes,

You will not be sorry choosing System 3 paints.  I have used them on two boats now and have been very happy.  I rolled and then touched with foam brushes. 

I am happy with the looks.

Dale

[wkisting]

Arrrrrrgh.... rain and chilly weather has kept us from making ANY progress for over a week now on our CS20. Going to head up to the local marina today and scope out outboards since I know it will start raining again if I attempt any fillet/epoxy work.

Think I might get the Tohatsu/Nissan/Mercury 3.5hp motor after talking to lots of folks about the Honda 2hp. The Honda sounds very reliable and probably just adequate to push a CS20, but several people have suggested to me that the air-cooled aspect might not be ideal for Georgia's very hot weather. (Two people told me it's not a good idea to run the Honda for long or very hard in 90+ Fahrenheit weather). So water-cooled will probably be a better choice for us, since we're most apt to need it in Georgia's hottest months (August, September) when the winds seem to die down to little or nothing.

The Tohatsu/Nissan/Mercury 3.5hp is all the same powerhead (technically, I think Tohatsu makes it) and it's almost twice the horsepower of the Honda for only 10 pounds more. I think 38 lbs. is probably a bit more than I want to hang from the transom, but it'll be easy enough to reinforce things back there to accommodate that weight. And I love the idea of a 4-stroke... no more mixing gas with oil, and lower fumes.

Anyway, thought others might be interested in knowing how I came to that decision. If I do end up getting it, I'll post a performance report about the motor after I finish the boat and get her in the water. Probably I'll post it at the building-log website: www.roguepaddler.com/coresound20.htm

[jaxsailr]

Hey Wes,

I would take a look at the Suzuki 2.5.  It is water cooled, had N-F and only weighs 30lbs and has an aluminum prop.  The Honda 2 will move a CS20 just fine.  It moved my Seaward fox and Peep Hen just fine.  Did not consider the air temp to be such a issue since it does have forced air cooling.  in the summer I use 30w or 15-40 in my air cooled engines.

Niels

[wkisting]

Hi jaxsailr,

I did take a look at the Suzuki (online), which is also a very attractive motor. I was told by someone on another forum that it DOESN'T have neutral, but I can't verify this from the Suzuki website: http://www.suzukimarine.com/sr_07/df2.5/features/  You may be correct, but it is strange that it wouldn't be listed on their website if it is equipped with F-N shifter.

We went up to our local marine dealer today to take measurements off the 3.5hp Mercury and (quite unexpectedly) came back with a new motor! They had one left, on closeout, at $200 under sticker! Couldn't pass it up. And I couldn't get over how friendly the service was... besides telling us about the motor and answering all our questions, they checked out our boat-building webpage, swapped boat-building stories, and also gave us a potential lead on a place to find mahogany trim for our CS20. I know folks in GA are friendly, but this was some of the most exceptional customer service I've ever experienced.... we spent 2 hours with them just chatting.    Nice folks.

Having handled the 3.5hp now, I have no qualms about hanging it off the transom. Feels lighter than 38 lbs., especially if you pick it up right after handling our 8hp Johnson. I think I'll probably fabricate a stainless bracket instead of cutting away part of the aft deck.

[ulpilotrmh]

Hey Wes:

I have a Tohatsu 3.5 HP, and it weighs 43 pounds. It's been a great motor so far. Just wish it had reverse.

Russ