Jump to content

Sign in to follow this  
cprinos

CS17 #315 continued

Recommended Posts

All this talk about foils. I can understand the difference it would make on a Hydrofoil Moth or some other high tech performance boat but on a Coresound 17 do you really think it is going to make such a difference? I would like to know since I too will need to make my foils sometime in the near future. In the past I have used a belt sander for shaping and then finished off with my random orbital sander with good results. At least I thought. I would like to know what others have done and do you really think that you are going to get an extra half knot out of your boat? If so, I'm in.

 

Alex.

Share this post


Link to post
Share on other sites

ha ha... no I'm sure my poor sailing skills will erase any advantage in the foil shape, but I think given the time/effort it's going to take to shape it anyway, I don't think using the templates will really add any more time to that -- actually to the contrary I have found that I do better with having a bit of a guide/template to follow rather than trying to shape this kind of thing by eye/feel.

Share this post


Link to post
Share on other sites

FOIL !!! Hey, a centerboard & rudder with a sweet foil shape looks way more cool than a square edged board. Curves are nice - one reason I like women . ..

Share this post


Link to post
Share on other sites

No pictures today, but some progress. I took an initial shot at fitting the centerboard trunk side with the longer rail that reaches to the forward bulkhead to help visualize placement of the trunk in the cockpit and also see where I'll need to cut the hole later for the trunk . No vertical trimming yet, just double checking that I've got the correct fore-aft position of the trunk. I still need to glass the trunk sides. 

 

The delivery man brought some goodies today -- 6oz cloth for the centerboard & later the hull, and I also got the mast tubes in today. I'm opting for the aluminum masts vs fabricating birdsmouth wooden sticks.  I like the aesthetics of wooden masts better, but I think given the lighter weight, [likely] quicker construction time, and more predictable bending characteristics, for me the scales tipped towards aluminum. A quick trial join of the sections showed that the masts will be quite light (granted fittings and the wooden cap will raise the finished weight a bit) and I don't think they will be to hard to wrangle around into the mast steps.

 

My lower mast sections are 2.5" x 0.125" x 2.25", and they have a snug fit to the middle (2.25" OD) sections, whereas the upper (2" OD) and middle sections have more room. I'm reviewing the plans and see it calls for creating small fiberglass bushings... that is pretty straightforward for the upper-to-mid join, but I'm not sure how there will be room for bushings in the lower-to-mid join. I think I remember reading something about this in the forums, so will have to do some research there.

Share this post


Link to post
Share on other sites

 but I'm not sure how there will be room for bushings in the lower-to-mid join

 

With that wall thickness you'll probably have to ream the lower out a little to get it to fit.

Here's a photo of Charlie Jones custom reamer for this task.

untitled.bmp

Cheers

Peter HK

Share this post


Link to post
Share on other sites

hmmm, I did not think about the reaming option. Is the important thing to keep there from being metal-to-metal contact on the tubes? In other words, if the existing fit is snug for one section, are the bushings necessary? I've got some time to ponder the point, I won't be doing work on the masts right away. I think they would be easy enough to do, but I'm not sure where I would store the fully assembled masts at the moment where they would be safe from damage -- maybe I'll just get a set of hooks for the garage wall studs to hang them up.

 

I'm jumping around a bit on the build here (I'm easily distracted). There was some nice mahogany at the lumber yard, so I took a shot at gluing up the thwart. Fir is being used for the the center accent strip.

 

Posted Image

 

Next I'll either glass the trunk sides or shape the centerboard, depending if I'm in a goop 'n glass mood or a hand-planing mood.   Or maybe I'll get distracted again by those shiny mast tubes and work on those.

Share this post


Link to post
Share on other sites

 

Is the important thing to keep there from being metal-to-metal contact on the tubes?

I'm sorry I didn't make things clear. The bushes are only to fill a gap when the diameters mean there is a loose fit. With the al tubes the fit is tight and reaming is necessary to get them to slide together. I used epoxy as a lubricant while sliding them together and as the glue to hold them together with no bushes. There is no problem with metal to metal contact when it's the same metal. I fitted a track so my masts are fixed in length.

 

 

If you want the masts to disassemble then make it a loose fit. 

 

Cheers

Peter HK

Share this post


Link to post
Share on other sites

quick pic from the other day when I was trial fitting the trunk side with the long rail. Thwart also shown in postion, but it is not yet let into the top of the trunk rails or trimmed for the seat-to-seat widths

 

Posted Image

Share this post


Link to post
Share on other sites

uggh. minor setback.  Been away from the build for a bit with work & vacation, and came back to look at shaping the centerboard.   I cut off the bottom tip of the board (I was planning on re-gluing a piece cross-wise so there would be no end-grain at the tip, plus the end would be isolated by a glue line).

 

Once I did that I saw some of the strip glue lines on the interior looked starved. I tried to break the sawed off piece in my hands, and was able to with a little bit of effort, and the break was at the glue lines. I had clamped it too hard when I glued up the boards.  I actually had a suspicion I might have screwed this up when I first did it... I was rushing at the time and doing the glue up in my basement--away from my epoxy station in the garage, so I was trying to stretch more coverage out of the mixed batches then I should have. With less epoxy on the strips then I should have had, I ended up with too much clamping pressure to get squeeze out.   I'm frustrated that I didn't listen to myself when I thought I was rushing it, but at least I found it before I invested any time in shaping the centerboard (or worse.... using it in the final boat). I should know better, and wasn't even going to post about this part, but I know I learned a lot by reading about other people's mistakes, so here's my contribution  :)

 

So, I got more fir, ripped some more strips, and glued up another centerboard. More epoxy was used. I took my time. The second one came out very well, so I can layout the profile and will also cut a channel for the rope-trick leading edge. The downside is I wasted some time and  wasted some money on the fir, but on the other hand, the new fir boards I used were tighter grained and significantly lighter (douglas fir really has a lot of variance on weight) than what I used the first time around, so I think it will be better in the long run.

 

chris

Share this post


Link to post
Share on other sites

Thanks for the update photos.  The CB fitting photo is quite instructive.  I hope to be at that stage at some point in the next couple of months.  keep the photos coming!  

I think we may be able to have a Northeast CS regatta!  Boston Harbor?  Narragansett Bay? Salem Sound?  Pleasant Bay? all great areas within a couple of hours for both of us. 

Share this post


Link to post
Share on other sites

Sounds like a good idea David. Since I haven't owned a sailboat previously, I've been limited to spots where I could find rentals, I'm looking forward to finding some new locales.

Share this post


Link to post
Share on other sites

Well, I got plenty of ideas after seeing all the boats at this years messabout. Good motivation for me to kick things into gear again.... I'm losing warm weather time for working in the garage, but have got plenty to finish up with the centerboard and rudder assemblies that can be tackled in the basement shop.

Share this post


Link to post
Share on other sites

I learn so much from you guys! hopefully if I get my butt in gear I'll catch up and contribute.....I'm retired for a year so I have the time. The regatta sounds good too.may do a New England swing this summer, boat in tow. Have a brother inNarragansett, a brother and sister in Duxbury, uncle on the cape, and will be doing a month in Maine around some courses. I'm intimidated by next steps. Don't really get the seat frames process as simple as they probably are as you get into it. Did the scarf joints today and will glue the glue strips tomorrow, and with luck install the vertical side panels sat.

Share this post


Link to post
Share on other sites

Chris-

Graham was once enough with my mast to try a method which worked quite well for him, which was cylinder honing the mast. If you do a you tube search for cylinder honing you will see how it works and it seems like a common automobile process.perhaps your auto mechanic could do it for you or loan you the tool.

Share this post


Link to post
Share on other sites

Thanks Lennie, there's a post earlier about a home-made reamer... The fit on my tubes is tight but I don't think it will take too much reaming to get them to slide. At the messabout Graham also was telling me about another way.... keeping the outer tube warm inside and putting the smaller tube out in the cold overnight. Epoxy them up and slide together before the temperatures equalize and they bond together. I think you only get one shot at that though.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.