Thanks: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 346 to 360 of 513
Thread: GIS Yawl
-
3rd August 2011, 02:08 PM #346SENIOR MEMBER
- Join Date
- May 2008
- Location
- Portland, ME USA
- Posts
- 837
-
3rd August 2011 02:08 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
3rd August 2011, 05:36 PM #347Senior Member
- Join Date
- Dec 2009
- Location
- Texas
- Posts
- 319
Clint,
I like the adjustments to the Yawl Rig you have made. Keeping the water out of the front mast step is more of a maintenance issue than a sailing issue. Bigger drain tubes will help. When we finally got the mast out, it was stuck after 6 days of sailing, there may have been as much as a ½ gallon of water trapped in the front mast box. With the new aluminum tube design you have invented that amount of water will never accumulate in the mast step. With my forward box full of water I was carrying about an additional 4 pounds of weight in the front of the boat. With your new design that will never happen.
My mizzen placement does tend to be left handed. With the mizzen moving closer to the centerline the boat, it will be more neutral on both tacks.
Moving the mizzen aft will help the boat track better. I have not felt any undue pressure on the rudder with the mizzen located where it is on my boat. So moving the mizzen back a little will help the yawl rig track even better. My concern is how to tie the mizzen sail tack down. I tie my mizzen tack down to a pad eye just behind the mizzen. That means it’s between the mast and the transom. So with moving the mizzen mast aft, the tack will need to be secured in a different way. The tack downhaul is the only thing attaching the mizzen to the boat. In the event of capsize; the downhaul is the only connection between the boat and the mizzen mast.
We had the mizzen mast slip out of the lower step during a hard and long pounding to windward a few weekends ago. We noticed the mizzen swinging around after we got to a little island for lunch. I believe it was more of an issue of the mizzen downhaul was not tight enough. Another idea might be to add another 20mm of timber the lower partner. That way the mizzen cannot bounce out of the lower partner as easy. On both Texas 200 events we never had this happen and it has only happens once. So this event is rare.
I think the adjustments you have made will fine tune the rig and make it even better.
Best wishes
-
4th August 2011, 07:27 AM #348Senior Member
- Join Date
- Mar 2010
- Location
- Queenstown New Zealand
- Posts
- 382
Thanks, Clint.
I'm thinking of getting a two piece fibreglass mizzen made on a tapered mandrell, probably about 55 mm ID/60 mm OD at the bottom, tapering to about half that at the top. I could look for a windsurfer mast, but if I get one made, I'll be able to get it optimised for stiffness at the bottom. Should be reasonably cheap in fibreglass, carbon probably isn't worth the 5 time price for the weight saving at this size.
Other ideas: (good or bad?)
Put the mizzen step on top of the aft tank and the partner near the top of the transom inside face. Partner with a half round cut-out and lashing to hold mast in place. Needs the top of the transom to be strong enough, but I think mine is.
Saves cutting a hole into the aft buoyancy tank and should make it easy to drop the mizzen and put the whole thing away if I want.
Leave the main mast step/partner as is. My centreboard slot is wider at the top, extended forward from standard, so I can angle the centreboard more than standard and move the CLR back at least 6 inches, which should have at least the effect of moving the main mast forward.
I'm curious to hear your thoughts.
Ian
I'm thinking of a later design, SOF folder, kind of a sailing canoe but with a transom, a bit like a slightly bigger version of Dave Gentry's Ruth, but on the concept that Keyhavenpotter and John Welsford are working on with their Nautilus - good sliding seat rower plus fast sailing canoe plus room to sleep inside, so I'd be able to use the mizzen mast as a stowable main mast for this design.
-
4th August 2011, 01:01 PM #349SENIOR MEMBER
- Join Date
- May 2008
- Location
- Portland, ME USA
- Posts
- 837
John, Thanks for your comments. I will be going to you now for GIS expertise, so having your feedback is great.
Ian, Did you already make your aft tank? Good...even more fun to cut a hole...I'll likely convert a local Goat into a mizzen version. I will cut the tank open, build the step, then scarf the tank back in place. Easy with a grinder, spokeshave, a little ply to double up the scarf underneath if any at all. That is what I would do. I think the glass mast is a fine idea. I have to say I picked up a carbon mast on a boat with a lug about the size of the gOat...it was striking how much lighter it was than even a birdsmouth with spruce and light scantlings. Glass fiber would be fine for a mizz.
CheersLast edited by CCBB; 4th August 2011 at 01:11 PM. Reason: Some photos on my mast partner set up
-
27th November 2011, 09:15 AM #350Senior Member
- Join Date
- Mar 2010
- Location
- Queenstown New Zealand
- Posts
- 382
Hi Clint, (or John Goodman), do you have a weight for your (I presume hollow birdsmouth at about 2 inch OD?) wooden mizzen mast?
I just got my fibreglass mizzen, it's wound on a 50mm dia tapered mandrel, 2.5 mm wall at the base going down to 1.5 mm wall and 25 mm ID at the tip. Stiffness about 30 % more than a solid 50 mm diameter wooden section.
Looking at the numbers for strength and stiffness for fibreglass versus wood, I think I could have spec'd it a bit lighter, perhaps 2.0 mm wall at the bottom down to 1.3 mm wall further up, stiffness would be about the same as the wooden stick, but ultimate strength of the glass mast would be a lot higher as it would bend a lot further before it would break.
Weight about 2 kg, I could have done it in carbon at about 1.3 kg for about seven times the price but saving 600 - 700 g didn't seem worth that much money.
It's sleeved in the middle so it comes apart into two 1750 mm pieces so I can keep it stowed up the front of the boat, decide if I want to use it just before launching.
I'm going to see if I can manage the balance with the mizzen by just moving the mainsail a bit further forward on the mast, and angling the centreboard back a bit. (My centreboard case is a bit wider than standard at the top so I can adjust things a bit more than normal)
Ian
-
27th November 2011, 02:31 PM #351SENIOR MEMBER
- Join Date
- May 2008
- Location
- Portland, ME USA
- Posts
- 837
Ian, I have no idea what mine weighs. I still need to get a scale for the shop. When I do, I'll report out.
Cheers
-
28th November 2011, 02:12 PM #352Novice
- Join Date
- Jul 2009
- Location
- Florida Panhandle
- Posts
- 20
Ian
I just ran out in a rain shower to weigh my mizzen mast thinking I may have a weight you could use, wrong. As it turned out my finished birdsmouth Sitka spruce mizzen mast = 3302 length, 50.8mm down to 28.575mm weighed in at a whopping 3.95kg. I think I could have made a solid stick and it wouldn’t have weighed any more. It must be all those coats of clear coat and varnish. To get down to 2kg I’ll have to go back to the drawing board.
Rod
-
29th November 2011, 10:44 AM #353Senior Member
- Join Date
- Mar 2010
- Location
- Queenstown New Zealand
- Posts
- 382
Hi Rod, it's great to have the data point, thanks for taking the trouble.
I can figure out theoretically how heavy a 50.8 mm dia, wall thickness 20% of OD 3.3 metre long tube from spruce (density 480 kg/cu m?) should weigh, it should come in not much more than 2.2 kg, a solid stick of 50.8 mm calculates as 3.3 kg or so.
I suspect the difference is in the blocking and the weight of epoxy that goes into a birdsmouth spar, it must be quite a high proportion of the weight especially at these smaller diameters. Also as you say the epoxy and varnish you put on the outside to protect it adds up.
Again, in theory a hollow mast should save 40% over a solid one of the equivalent stiffness and strength, but perhaps there is nothing in it at these smaller diameters.
I'm curious if Clint can get any data on all the birdsmouth spars he makes once he gets a set of scales for his workshop.
These mandrel wound fibreglass spars represent pretty good value for money - my two piece mizzen mast cost about $150 inc tax for nearly half the weight of a wooden one, to get one done in carbon would have cost $800 +, for a weight one third of the wooden one (1.3 kg).
Ian
Edit and correction: I got the tape measure out and a more accurate set of scales, my fibreglass mizzen is 3400 mm long, it weighs 2000 g without the joining sleeve, with the joining sleeve it weighs 2250 g.
I'm going to step it on top of the aft tank, with a partner on top of the transom, so I'll cut 300 mm off it so it's effective length is the same as on Clint's plan.
-
2nd March 2012, 03:55 PM #354SENIOR MEMBER
- Join Date
- May 2008
- Location
- Portland, ME USA
- Posts
- 837
Well, my Goat is painted. It has been a haul. I WILL sail my bumm off this season. Very happy with the finish. I was going for really nice, but not nec. yacht finish. This skiff will get used. NO VARNISH!
006 by Clint Chase Boatbuilder, on Flickr
I think I will name the boat Flicker. Not 100%. She has character now with the paint, so the name should come more easily.
I still need to make my oars. Actually, I have a pair of GIS oars that were for somebody but they have not been picked up.
-
2nd March 2012, 04:06 PM #355Senior Member
- Join Date
- Jul 2006
- Location
- Portland, Oregon, USA
- Posts
- 334
-
3rd March 2012, 12:56 AM #356
-
3rd March 2012, 01:45 PM #357SENIOR MEMBER
- Join Date
- May 2008
- Location
- Portland, ME USA
- Posts
- 837
The interior is Brightsides Seattle Gray. I have painted a couple dories with it and it is really lovely even in bright sun.
I'll get some hardware on this weekend.
-
4th March 2012, 01:54 PM #358
Howdy.
I always find the discussion about painting interiors of open boats or decks of bigger boats in white interesting.
I've sailed on bigger boats with pure white decks and never found it a problem. The brightest things are the sun and the water. And then when it is overcast or dusk the white decks are really nice.
Michael
-
14th April 2012, 07:15 AM #359
Clint, I hope you're GIS build is progressing well. I have two yawl-related questions for you, one for each end of the vessel.
1) What are your thoughts on a square section mizzen mast? Would that be incompatible with the sprit's snotter set-up? My main mast is square and I do appreciate the lightweight construction method. It's not a deal-breaker for me; if I have to do a round mizzen I can live with it.
2) Do you think the forward main mast step is essential? Or is it technically correct but undetectable by recreational sailors? [John G. and/or MIK's experience with the set-up might be invaluable, but as the designer of the Yawl variation, I wouldn't want to ignore your opinion.]Dave
StorerBoat Builder, Sailor, Enthusiast
Dave's GIS Chronicles | Dave's Lugs'l Chronicles | Dave's StorerBoat Forum Thread
-
14th April 2012, 08:45 AM #360Senior Member
- Join Date
- Dec 2009
- Location
- Texas
- Posts
- 319
The other yawl sailor will chime in here:
1. I am building a Jim Michalak, Hap's Cut and it has a solid square mizzen mast. If you can build a light weight mizzen mast using the same technique as the main mast go for it. A solid mizzen mast is too heavy for a GIS. My GIS mizzen is a birdsmouth and it has performed well in every condition I have sailed in. (Thanks to Clint, he made it for me)
2. I have played with sailing in yawl configuration with the mast in both front and normal locations. The front step is a must for the long distance cruising I do. That extra few inches of separation between the mizzen and main mast helps the boat track and stay on course. The front mast step's only drawback is that it pushes the boom/tack of the sail closer to the front of the very narrow bow. Mik and I had no trouble with him in the rear of the boat and me way up front. When reefing by myself I can feel the transom get pretty light as it lifts up in the waves while I am tying the new tack in. ( I weigh 205 lbs) Here is a picture of Mik and I tying in a reef in 20knots of breeze and "flat" water during the Texas 200.
I found that with the main mast in the normal position the mizzen can cause more weather helm with less sheet tension. Off the wind it sails about the same but when close hauled the mizzen becomes less effective and pushes the boat into irons easier during a tack. We found releasing the mizzen just before "banging" the tack made the boat roll over to the other tack nicely. Get the main powered up then slowly sheet the mizzen in. With the main mast in the forward step we could be a little more lazy when tacking.
Similar Threads
-
BETH (kamikaze canoe yawl) -questions for Boatmik
By robhosailor in forum Michael Storer Wooden Boat PlansReplies: 7Last Post: 18th October 2007, 02:16 AM -
Yellowtail Yawl Update
By Daddles in forum BOAT BUILDING / REPAIRINGReplies: 5Last Post: 26th July 2006, 12:07 PM -
Introducing, the Yellowtail Yawl
By Daddles in forum BOAT DESIGNS / PLANSReplies: 19Last Post: 16th June 2006, 06:31 PM -
Caledonian Yawl Plans
By Donald in forum BOAT BUILDING / REPAIRINGReplies: 1Last Post: 9th February 2004, 10:10 AM