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Old Feb 11, 2013, 08:50 PM
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poltergeist's Avatar
Pomona, CA
Joined Apr 2007
705 Posts
Richard,

My jib boom is about 465mm long with a small "bullet" lead weight threaded into the front tip. The forestay attachment (jib tack) is 90mm from the front end of the boom, while the jib pivot attachment is 150mm from the front end. With my current tune, the end of the jib boom comes within about 8mm from hitting the mast.

My forward-most deck eye for the jib pivot attachment is 175mm from the tip of the bow, and 15mm between each eye. Hopefully that makes sense.....here's a few pics.

Kevin
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Old Feb 13, 2013, 03:57 PM
RB
Joined Nov 2012
116 Posts
Kevin,
Thanks for the dimensions and pictures - they are both very helpful. I like the grommet you've used for the jib boom attachment; it gives another level of adjustment. I've gotten to the point where I could finish up fairly quickly; but with winter here (Niagara, Ontario), there is no real hurry.
Thanks again, Richard
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Old Feb 14, 2013, 06:53 PM
RB
Joined Nov 2012
116 Posts
Rigging Question ??

On many boat designs; the lower shroud is generally fastened to the deck aft of the upper, as opposed to being forward; why??
Richard
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Old Feb 14, 2013, 08:08 PM
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poltergeist's Avatar
Pomona, CA
Joined Apr 2007
705 Posts
Richard,

The Canterbury is rigged similarly to my "big" boat, a Moore 24. As the backstay is tensioned, the mast bends, with the middle of the mast bowing forward. The aft placement of the lower shrouds, provides a way to tune how much the mast can bend.

Tight backstay and loose lowers means more mast bend, and a flatter mainsail.

Loose backstay and tighter lowers means less mast bend, and a fuller mainsail.

Kevin
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Old Feb 15, 2013, 09:24 AM
RB
Joined Nov 2012
116 Posts
Kevin,
Thanks again. The key being the aft placed lower allows control of mast bend where a forward placed lower cannot.....but what of the boats with no lower and no spreaders ?
Richard
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Old Feb 15, 2013, 11:26 AM
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Joined Jun 2009
88 Posts
Mast Shape Control

If the boat is only used for recreational sailing, the concern would only be that the mast is stiff enough to absorb the loads transmitted from the wind to the sails and thence to the mast. If however, the boat is used for racing, being able to shape the mast with the backstay and lower shrouds is absolutely critical in allowing the sails to take their proper shape and produce the maximum amount of power from the wind to drive the hull. I sail for recreation and I race, but in either case I want to have maximum power available so routinely choose a single spreader with side stays, and lower shroud arrangement that is typical of boats like the EC-12 for the standing rigging.

The question of what kind of luff curve has been built into the mainsail must be investigated also. Many kit sails are cut with a straight luff, so the mast should be maintained as straight no matter what the wind speed.
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Old Feb 18, 2013, 12:36 PM
If it floats....sail it!
FoamCrusher's Avatar
Elk Grove, CA
Joined Sep 2002
4,188 Posts
Elk Grove MYC Canterybury J First Race

The Elk Grove MYC (http://egmyc.net/) held its first race this season with the fleet expanded from Seawind's and US1M's to include Canterbury J's for the first time. Four boats were completed and in the water for opening weekend, with another 5 still under construction. Several should be RTR for the second club race in late March and even by March 3 when the other local club - the Sacramento Model Yacht Club (http://sacmyc.net/) has invited the CJ's to sail with them this year. The fleet may inspire a few others to build their own boats after watching the EG fleet's close racing.

The winds were light and fluky yesterday - typical of Elk Grove Pond which is down in a bowl surrounded by trees - and the strong afternoon NNW breeze predicted by the weatherman failed to materialize, producing some very close racing. Several of the finishes had all four boats within a few meters of each other after a full Olympic course (triangle + windward, leeward).

One club member brought out a second boat for testing by a prospective buyer, but when the would-be buyer arrived and announce he had bought his own kit and was no longer not interested in the completed boat, yours truly jumped on the opportunity to buy the well finished boat - Hull #527 - at a bargain price.

With no time for testing or tuning, I put the boat in water and went racing, doing rather well, placing 2nd over the eight races.

The boat needs attention to a few minor items, like the addition of a jib topping lift, but otherwise is in excellent competitive shape and has a far better decking job than I could have done.

While the CJ does not have the sports car like handling of a US1M, it looks so graceful on the water and that integrated keel/rudder will allow me to sail in my backyard pond without stopping every few minutes to remove hitch-hiking aquatic weeds!

See a few pictures below taken by one of the other club members.

FC
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Last edited by FoamCrusher; Feb 18, 2013 at 08:11 PM.
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Old Feb 18, 2013, 03:46 PM
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Ed Crowell's Avatar
Southern Calif
Joined Dec 2005
1,856 Posts
FC,

I am glad to see some organized racing with C-J's on the west coast. Please keep us informed of your events. I wish I lived closer so I could see your boats and sail with you guys. Your boat looks very nice.

Ed
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Old Feb 18, 2013, 07:43 PM
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poltergeist's Avatar
Pomona, CA
Joined Apr 2007
705 Posts
That looks like fun!!!....too bad it's a looooong drive for me. I'm assuming your regatta's are part of a yearly series? If I were to make the drive, could I enter for just the day/weekend and race "unofficially"???

Kevin
Canterbury J #551
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Old Feb 18, 2013, 08:35 PM
If it floats....sail it!
FoamCrusher's Avatar
Elk Grove, CA
Joined Sep 2002
4,188 Posts
Kevin:

I understand that it is a long drive for just 8 heats, but visitors are always welcome without any dues or fees, for either club. (I am the Secretary/Treasurer of the Sac club so I will refuse your $!!!).

The two clubs share one venue and each sail in another different venue, so if you are in the Sacramento area on the Sunday of one of our scheduled races, PM me and I will vector you to the correct location.

Both clubs have a regular racing schedule; For Elk Grove it is once per month in Feb, March, Oct and Nov, and then 2X/month April through September. Sac MYC sails 1X/month March through November in addition to the EGMYC schedule. See the links in my post to and use the tabs to look at the schedules since they are not a consistent weekend (like every 2nd Sunday) like some clubs do.

Yesterday, the EG club discussed the possibility of hosting a Region 6 CJ regatta, but felt that we want to wait until we have more boats in the water and a full season of racing for the newer skippers before we host a regional event. We know we can do it since we successively hosted the R6 Seawind Championships this last year at our West Sacramento venue - a larger lake with much more consistent winds than at Elk Grove Pond.

A R6 regatta would be two days - 16 races on Sat and 12 on Sunday, so that might be worth the trip. If we get enough interest, we might even apply to host a NCR a some point down the road.

I will keep posting how things are progressing and potentially more pictures until someone tells me to stop

Now if we can get some interest going in San Diego......

FC
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Old Feb 18, 2013, 09:53 PM
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Ed Crowell's Avatar
Southern Calif
Joined Dec 2005
1,856 Posts
FC,

I started this thread to promote interest in the Canterbury J. So please post pictures of your boats and information about your Regatta's. It would be nice to know how the boats were constructed such as what materials, servos and sails were used.

I recently removed my aluminum booms and replaced them with carbon fiber. I am now closer to the minimum weight of 14lbs 5oz. It now weighs 14lbs 6 1/4 oz.

Ed
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Old Feb 19, 2013, 01:13 PM
If it floats....sail it!
FoamCrusher's Avatar
Elk Grove, CA
Joined Sep 2002
4,188 Posts
Ed:

Will do with the pictures and possibly the construction details for the other boats. What I do know about them is that they all have either planked decks or veneer planking over ply. Each builder is going with a different color scheme and deckhouse design so they all will look very different.

As you can see from the photos below, #527's hatches slip over mildly raised rails making them resistant to water intrusion. The builder of my boat made a smaller raised section for the aft hatch on his boat with the larger opening cut directly into the deck without raised side rails. He is now second guessing himself saying that his boat is taking in some water where the deck is cut and now wishes he had made the raised type rear hatch on his boat too. While my hatches are an easy press fit and the boat remains dry even when dipping a rail, I will be adding some rare earth magnets in the corners to keep them firmly closed and attached. The circular skylights on the hatch will either be painted black or drilled out and clear plastic glued in from below to make them appear more scale.

My boat has an aluminum mast with CF arrow shaft booms, with Rod Carr sails. After sailing it some, I think it needs a jib boom counterweight for our usual light air conditions, but I will make the fitting so that it is easily removable for when the wind picks up.

The boat has a dual arm double purchase sheet system driven by a HS-805BB with a servo stretcher and a HS-645MG for the rudder. The power is from a 1.3Ah 6V gel cell battery pack (very heavy for the relatively modest capacity) that sits on top of the keel, and brings the boat in at about 30 grams over min weight.

The rudder servo is fine, but I didn't like the feel of the sheet adjustment due to the vagueness caused by a servo stretcher that was necessary to give sufficient arm rotation, so I modified the radio board last night and will be putting in a HS-7945SH digital servo that has native 180 degree rotation and much more torque.

The boat doesn't really doesn't need the additional torque, but I use that servo on my US1M's because I like its precise feel, I can adjust its speed and it has overload protection built into the servo so if something jams you don't have an "engine room fire" like one of the Infinity-54's in our fleet had, complete with flames and billowing smoke

The standing rigging looks to be 80 lb Sevenstrand nylon coated fishing wire leader and because the shrouds were installed a little long (the shroud adjusters are down tight and the wire is still not really tight enough for strong winds) I will be replacing them with 0.008" solid SS wire which will also lessen the windage of the rigging.

Since the new servo is lighter than the original, and with the other changes, I may have to add a small corrector to bring the boat back up to min weight, but we'll see.

FC
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Old Feb 20, 2013, 12:40 AM
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poltergeist's Avatar
Pomona, CA
Joined Apr 2007
705 Posts
Nice looking boat Steve. Gotta agree on the Hitec digital servo for the sheeting. Light, powerful and very precise. Maybe when we get a few more boats built down here we'll pool our resources and make a roadtrip up there. A regional regatta would be a lot of fun, and make the drive a little more "worth it".

Anyway, congrats on your new boat and C-J fleet!!!

Kevin
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Old Feb 20, 2013, 09:47 PM
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Fairwind900's Avatar
Visalia CA
Joined Jul 2007
884 Posts
516

Playing with chain plates.

I purchased aluminum picture frame kit at Hobby Lobby so I could cut it up and make chain plates and a jib rack. I worked on the chain plates today.

I took the L brackets and mounted them into a 2-way cross slide machinist vice. After adjusting it and installing a 1/8" bit. I drilled 9 holes in the L bracket. Then test fitted it on the deck.

I need to round off the square edges and find screws I want to use. But that was today project.

Rick
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Old Feb 21, 2013, 06:54 PM
RB
Joined Nov 2012
116 Posts
More Musing ...

I once bought a small sailboat with the name More Malarky - maybe that is closer to this post.

I've ordered Sirius Sails and in that activity got to studying pics of boom sail attachment details. The norm is to use bowsies for adjustment, but I also found a pic of (I think) an EC or US 12 showing sail draft adjustment using a hook set into a series of holes along the booms. That sounds interesting and should be far more precise than wrestling with bowsie adjustment.

Now this got me thinking - are sail adjustments as critical on a model as on a full size sailboat ? On a full size boat an adjustment to the jib could be as little as 1 inch. On a model that might translate to a sixteenth of an inch. That is difficult to do with bowsies; but will that level of adjustment produce a similiar effect to that of a full size boat ? Or, perhaps the question is what is the minimum adjustment that will show an improvement in performance ?

It's winter here and ones mind does seem to wander,

Richard
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