Wishbone booms

[Tom the rower]

So, now that Sambasailor and Sailsalot have finished the EC in their Core Sound 17 with wishbone booms, could someone explain why the wishbone booms are "hi tech" and possibly better than just the normal cat ketch rig?  I am about to start a Core Sound 20 mk 2 (in hand already), and I know, it will be a while till I  need to worry about masts and such, but, not coming from a sailing background, I wonder why they are so highly thought of, at least by Sambasailor and Sailsalot.  Thanks

[Dnjost]

Tom,  I think the wishbone gives the advantage of not interfering with the sail shape on either tack.  The draft should remain undisturbed by the sprit, not allowing for sprit compession.  I know that Phil G. also had 3D laminated sails from North made for his boat, these sails keep their shape through a very broad range of winds and would not be worth the investment without the wishbone rigs.  Combined with the carbon spars, his boat obviously flys.  Looked like one tactical error at CP2 in the EC that put him behind.  Bet he could have won it!  

 

that said.  I have decided to go low tech on my CS17.  the pockets are not that deep these days, and it will still result in a darned nice boat to sail!  

 

I could always upgrade later on...

 

david

[Tom Lathrop]

Tom,  I think the wishbone gives the advantage of not interfering with the sail shape on either tack.  The draft should remain undisturbed by the sprit, not allowing for sprit compession.  I know that Phil G. also had 3D laminated sails from North made for his boat, these sails keep their shape through a very broad range of winds and would not be worth the investment without the wishbone rigs.  Combined with the carbon spars, his boat obviously flys.  Looked like one tactical error at CP2 in the EC that put him behind.  Bet he could have won it!  

 

that said.  I have decided to go low tech on my CS17.  the pockets are not that deep these days, and it will still result in a darned nice boat to sail!  

 

I could always upgrade later on...

 

david

It was not a tactical error that delayed them but a tactical decision not to attempt Florida Bay at night.  Since they were rookies in this event, I suspect the decision was a wise one.  Allan has five previous time navigating this difficult stretch and was able to carry on fairly easily.  Which of the two boats is really faster is still a question.

[ecgossett]

The twenty could probably do circles around the 17 if it had carbon masts, fancy sails, and wishbone rigs. Imagine what a CS20 MKII could do with that setup, and water ballasting.

[Tom Lathrop]

The twenty could probably do circles around the 17 if it had carbon masts, fancy sails, and wishbone rigs. Imagine what a CS20 MKII could do with that setup, and water ballasting.

Well, maybe.  There is much more to speed potential than three extra feet of waterline.  Given the same hull and rig design such as with both CS 17 and CS20, the main factor in generating speed  is power to weight ratio.  The high tech stuff is nice but only in so far as making more power and/or efficiency in application of the available power.  When planing, waterline length is not a good measure of speed.  Less waterline length can promote faster speed. 

[Dnjost]

Tom -

 

thanks for the update on why Phil and Allen decided to take the route they did.  I am obviously not in a position to be doing an armchair sailor thing, and hope no offense was taken.  I hope someday to do this event, and have a lot of respect for those that did it!   

 

I did read that the 20 busted a mast when a sheet got snagged on a navigation mark.  They were still making excellent time. 

[Tom Lathrop]

No offense taken.  Graham actually did the a similar thing in his first EC Challenge for the same reason.  They not only busted a mast, they busted the mainmast at night in Florida Bay and finished the race under mizzen alone.  They would have easily broken the two day goal otherwise.  One of the features of the cat ketches that is not well appreciated.  Under many normal conditions, the B&B cat ketches can tack and even make windward distance under mizzen alone.  Something I discovered long ago in LOON, one of the first BRSs built as a sailboat.

[Mike Vacanti]

I thought that Graham broke a sprit in 2007, not a mast.

[hokeyhydro]

I thought that Graham broke a sprit in 2007, not a mast.

I believe you are correct, Mike. Tale I read claimed a sprit shattered.

I doubt blowing up even a "closet pole" sprit would happen with the average CS pilot, but with Graham tuning the rig it's sort of like hitting the nitrous bottle on a Hemi. Poor cedar pole wasn't rated for that kind of horsepower :-)

[David M]

I think Tom was refering to Grahams waiting for daylight to cross Florida Bay, not the broken spar.  That was what cost the CS 17 this years race.

 

Judging by the photos from the start the CS 17 may have also had a bow sprit and ability to fly a spinnaker so both boats had far larger sail plans the the stock CS17 & 20's.  It will be interesting to see any upcoming reports from the crews to see how much of the time they were reefed vs. flying max sail with an a-kite or staysail.

 

Overall it seems like the conditions were very nice this year and clearly favored the sail boats over the paddle boats.

[Tom Lathrop]

I think Tom was refering to Grahams waiting for daylight to cross Florida Bay, not the broken spar.  That was what cost the CS 17 this years race.

 

Judging by the photos from the start the CS 17 may have also had a bow sprit and ability to fly a spinnaker so both boats had far larger sail plans the the stock CS17 & 20's.  It will be interesting to see any upcoming reports from the crews to see how much of the time they were reefed vs. flying max sail with an a-kite or staysail.

 

Overall it seems like the conditions were very nice this year and clearly favored the sail boats over the paddle boats.

A little miss in interpretation.  Allan and Paul lost their mainmast in Florida Bay this year, but won anyay.  Graham was able to repair his sprit after it broke.  Both CS boats have bowsprits.  We will never know which boat might have won this race if the CS17 had elected to continue.  The CS17 might well have finished in the same position (although sooner) if they had not elected to wait for daylight.

[Howard]

Back to Tom the Rower's original question, unless you are worried about serious racing, you can probably stick with the basic sprits as designed.

 

Advantage to wishbones on the smaller boats is ostensibly to obtain a better sail shape, and better performance, but since the sprits mount on opposite sides of the mast, the sprits are only affecting one sail at a time. If you wanted to wring out every possible bit of performance, you might want to consider them. Part of the advantage you gain is offset by the reality they are more complicated to rig. You either have to have them ready and step your mast through them, or build them to come apart at one end or the other.

 

On larger boats that are going to remain rigged for longer periods of time, wishbones may offer the same slight potential for performance gains, but also better sail handling, as you can install a lazy jack system under the wishbones to gather the fall of either a reefed or doused sail. Otherwise, the sail may go on the deck and somehow needs to be bundled up to stow.

 

Wishbones probably have an advantage when rigging a single line reefing system, but the reefing plan of the sprits is simpler (although I wonder how easy it would be to reef the sprit rig on the water when the wind is up and the sail is flogging the daylights out of itself and for good measure, try doing that at night).

[Peter HK]

Wishbones probably have an advantage when rigging a single line reefing system, but the reefing plan of the sprits is simpler (although I wonder how easy it would be to reef the sprit rig on the water when the wind is up and the sail is flogging the daylights out of itself and for good measure, try doing that at night).

I have reefing lines arranged on the standard sprits so I can reef the main from the cockpit quickly- they are permanently run.

Here's a short video to illustrate, taken on a calm day.

 

 

Cheers

Peter HK

[Randy Marshall]

Back to Tom the Rower's original question, unless you are worried about serious racing, you can probably stick with the basic sprits as designed.

 

Advantage to wishbones on the smaller boats is ostensibly to obtain a better sail shape, and better performance, but since the sprits mount on opposite sides of the mast, the sprits are only affecting one sail at a time. If you wanted to wring out every possible bit of performance, you might want to consider them. Part of the advantage you gain is offset by the reality they are more complicated to rig. You either have to have them ready and step your mast through them, or build them to come apart at one end or the other.

 

On larger boats that are going to remain rigged for longer periods of time, wishbones may offer the same slight potential for performance gains, but also better sail handling, as you can install a lazy jack system under the wishbones to gather the fall of either a reefed or doused sail. Otherwise, the sail may go on the deck and somehow needs to be bundled up to stow.

 

Wishbones probably have an advantage when rigging a single line reefing system, but the reefing plan of the sprits is simpler (although I wonder how easy it would be to reef the sprit rig on the water when the wind is up and the sail is flogging the daylights out of itself and for good measure, try doing that at night).

Been there, done that, as Graham's crew on the Southern Skimmer. After the cringles had been used a couple times, it was quite do-able. The first time was a bear. It is challenging, but manageable as crew if you are resonably fit. single handing woud be scary for me.

- Tinker

[hokeyhydro]

Wishbones probably have an advantage when rigging a single line reefing system, but the reefing plan of the sprits is simpler

Got me a tad confused - do tell, why is a reefing plan for sprits simpler than reefing with wishbones? Please keep any explanation in the "reefing for dummies" catagory since I have only worked with sloop rigs.

[Phil Garland]

Hi Guys,

 

Sambasailor, aka Phil Garland here; back in the real world after one of the most exciting races I've ever done.  Our hats are off to Paul and Alan on Dawn Patrol...they are very deserving of holding the record for Class 4 in the EC...and it probably will not be broken for a while.  

 

Dan and I were very exhausted when we reached CP 3 and stopped to eat and rest for 4 hr.  It was also a prudent mariner decision to not cross the bay at night for the first time.  Even with their mishap with the main mast we would not likely have caught them on Florida Bay.  We were not as fast as they were in normal displacement sailing.  We were only faster when we had big breeze and we could plane earlier than they could.  I must say the CS17 and 20 are very able boats and we were very impressed with their performance.

 

The wishbone booms were used as is mentioned above to keep optimum sail shape of the 3Di sails.  I would say the standard rig with sprits is perfectly adequate for most boats and is much easier to rig/unrig than the wishbones.  We had jiffy reefing set up on both booms and it was fairly easy to reef.  As we approached Cape Sable at sunset on Sunday night the wind came up to 25 kt with higher gusts so we reefed down as did Dawn Patrol.

 

We did have a bowsprit set up but only used the spinnaker and jib/staysail in light air.  For most of the race we were using just the main sails.  

[Dnjost]

Phil -

 

I am very impressed with both your boat building skills and your sailing skills.  congratulations on a great sail!

You represented us Northeast sailors well.  Makes sense that once both boats settle into displacement speed, the 20 wins.   

 

Once this snow melts, I can get the snowblower out of the boatbuilding garage and get started! 

[Howard]

Wishbones probably have an advantage when rigging a single line reefing system, but the reefing plan of the sprits is simpler

Got me a tad confused - do tell, why is a reefing plan for sprits simpler than reefing with wishbones? Please keep any explanation in the "reefing for dummies" catagory since I have only worked with sloop rigs.

 

Assuming most sprits are designed as shown on my Princess 26 plans, the clew end of the sprit is simply a dowel rod that fits into the clew grommet of the sail. I have a similar fitting / setup on the whisker pole of my existing sloop. To reef a sprit boom, you simply pull it out of the clew, and move it up to the higher clew/reefing point on the sail. From a design and build standpoint, that is much simpler than jiffy reefing etc.

 

But again, once you remove the sprit to move it, getting it back in place may not be easy, especially so if the wind is up and the sail is flogging and the boat is dancing. Doing that at night would be an even greater challenge and even more so single handed. I don't have any experience doing that with sprits, but have lots of experience doing it with my whisker pole. Under extreme conditions, it can be a real rodeo.

 

The advantage here to the wishbone rigged boat is there is no loss in control. The reefing line is captive and all you do is pull it. But then you do have the fall of the reefing lines to deal with.

[Joe Anderson]

Peter

 

I watched your video. You were able to reef very quickly, though you are right it was pretty quiet. Do you have details on how you have rigged the sprits for reefing? I think this was discussed in an earlier thread but I haven't been able to find it. I have been thinking about rigging a line to pull the clew down then resetting the downhaul in the reefing cringle. This would require getting to the base of the mast but does away with resetting the tip of the sprit into a flogging clew.

[Peter HK]

I watched your video. You were able to reef very quickly, though you are right it was pretty quiet. Do you have details on how you have rigged the sprits for reefing? I think this was discussed in an earlier thread but I haven't been able to find it. I have been thinking about rigging a line to pull the clew down then resetting the downhaul in the reefing cringle. This would require getting to the base of the mast but does away with resetting the tip of the sprit into a flogging clew.

Hi Joe

I found the old thread where I tried to show the way the reefing system is set up.

http://messing-about.com/forums/topic/7063-reefing-cs17/

 

In simple terms the clew is always shackled onto the end of the boom. A reefing line goes from the end of the boom up to the first reef eye on the leech, back down to the the end and then along the boom to a cleat at a convenient spot.

At the luff end I simply added another downhaul that goes to the reefing cringle and led it back to the cockpit (so you don't have to get onto the foredeck to shift the downhaul).

Reefing sequence is

1 Release halyard the right amount (I've marked it at the right length).

2 Pull down tight on the luff downhaul/reefing line that is clipped with an S hook to the reef point.

3 Pull on leech reefing line on the boom and cleat.

4 Tie the lines around the sail bundle to tidy up.

 

This has worked very well so far.

A topping lift is also good to stop the boom crashing onto the deck, and easing the snotter before reefing and retightening after seems to make it easier.

I have snap hooks to attach reefing lines and topping lift so it's very quick to rig.

 

Cheers

Peter HK