Spindrift 10 in Oz

[wardm]

Just sharing some pictures of S10 #524 which I completed on the weekend as a new tender for our AZULI F40 Cat.

General Spec's;

Gaboon Ply Hull

Foam Sandwich Blades

Alum mast base/Carbon mast top (old sailboard mast)

Hopefully I will get the sail this week so we can try her out.

Does anybody know if there are any other Spindrifts in Australia ?

[P Doug (WA)]

Very nice looking boat.  Wish you a good sail and hope you get pictures of the launch and sail.

[Greg Luckett]

Wow, another beautiful Spindrift.  Congrats and it is a nice looking boat.

I am inspired to get busy again on mine.

[john_banfield]

Nice boat.  Are you in Sydney?  I'd love to have a look.  We live in Darlinghurst, and just ordered the 11N plans.

Cheers,

John

[wardm]

Sorry, we are in Brisbane.

I just received my sail yesterday, so I hope to try her out this weekend.

I will try and post some photos of her sailing next week.

[wardm]

Just sharing some photos of my son and I sailing our new S10 on the weekend.

Everything was going great, until the wind picked up and the bottom mast section bent. In the photo below you can see the mast bending off below the boom

after a gust hit on a broad reach in about 15-18 knots of wind...

Another shot taken after we gybed, and started limping home...

We had to let the sheet right out and depower the sail so it would not bend further.

The 6061 T6 aluminium section specified in the rigging plan is very difficult to get hold of in Australia so I just used some 50mm OD x 2mm wall Aluminium that was available. Obviously it was too soft. I now need to try to find some suitable T6 tube from somewhere... it seems that T6 is much more readily available in the USA.

[Peter HK]

I had the same propblem with a Welsford dinghy- used the standard aluminium and bent it in the same place.

I then researched the subject especially with respect to my Cs17.

Standard alloy here in Oz is 6060 and even in T5 temper has an ultimate tensile strength of about 150 MPa. 6061 T6 has a UTS of 260 MPa. You have 3 choices.

One, you might find 6106 T83 drawn tube (a mandrel is pulled through the tube- suposedly densifies the alloy) in the right size and its UTS is 275 MPa.

Two, you can ring All Yacht spars in Brisbane and ask for Joel Berg's brother (can't remember his name) who imports a lot of 6061 T6 spars for dinghies.

Three, you could try http://www.onlinemetals.com. I ordered my sections from them, came in about 3 days and postage was as expensive as the aluminium.

Peter HK (here in Brisbane)

[wardm]

Peter, Thank you for the helpful information. I will pursue these options this week. 

I would also love to see your CS17 when it is finished.

Regards,

Mark

[Peter HK]

Mark

I forgot to mention that if you order 6106 T83 tube from Capral you have to buy a 6 metre length- makes it a bit expensive.

It may have been Joel Berg's uncle not brother I spoke to.

Current photos of my Cs17below- at this rate I hope to launch about March next year.

Peter HK

[PinoyPiper]

I live in the Philippines and it's impossible to find 6061-T6 tubing here too. so I used aluminum pipe for the lower section, (wall diameter around 3.8mm) it was fairly heavy but it worked. for the top sections I just used regular aluminum tubing.

2" aluminum tube on the left and 2" aluminum pipe on the right. (thumb included for scale)

[wardm]

Thanks again Peter,

I have tracked down some 50mm x 2mm 6061 T6 in Sydney. It seems the local yacht riggers don't carry this stuff. As you predicted, the freight costs for a 3m length is nearly as much as the tube. Your CS17 looks great, you are doing great job.

Thanks also PinoyPiper for your information, that's another option if I get really stuck.

Cheers

Mark

[david richens]

we have been toying with the idear of bamboo in the aluminum tubing what do you thik

[Designer]

Mark,

I am sorry to hear of your problems with the weaker mast material but that picture of your boat sailing with the bent mast is priceless.

I just ran the calculations with your mast new material using 6061-t6 specs. You are still 10% under specified strength due to the nearest metric size which is 13% smaller in diameter. Even though your wall thickness is 21% greater, it is diameter that counts most.

Is your new mast strong enough? I don't don't know for sure, it is probably within the safety margins but I would stuff an X shape wooden plug up as far as the gooseneck just for the day when you are thrashing hard to windward two-up.

[wardm]

Graham

Thanks for your reply and for running the calcs on my new tube specs. My wife took the picture at the right time just after a good gust of wind that caused the mast to start bending.

I like your suggestions to strengthen the critical area of the mast with an X shape wooden plug.

I was thinking of making the plug by laminating 2 layers of 6mm gaboon ply and then interleaving the sections to make the X shape, then filleting the joins with the same epoxy filler used for the boat, and coating the whole plug with epoxy resin. Does this method sound OK?

Alternatively, I have some 19mm Douglas Fir that I could use to make the plug?

Mark

[Designer]

Mark,

I would go with the fir because nearly half of the grain in the ply is going the wrong way.