Anonymous wrote:

The thin walled inner wood mast is really just a mold to wrap many layers of glass and carbon round to make a very stiff very strong mast. I wonder if any members have tried this combination.

I built two freestanding masts that way, a wooden strip mold covered with glass and carbon. They are not very tall, at 6.5 m and 8.6 m but I think it could work for bigger masts.

Rudolf

Hi Rudolf, that is very interesting to hear.

Can I ask a few questions?

How many layers of each did you lay and what type of weave did you choose. Do the glass and carbon bond well together and are there any tips you learnt you could pass on.

Thanks, Jim

Anonymous wrote:

Jim, first of all, hats off for you!
Only now did I realise that you have both designed and built your boat. I could never do that.

Now I have plonked my suggested sail with 60° yard on top of your sailplan with a gaffrig (GR). As you can see, the lead of the JR is much shorter than that of the GR. Still, I would not be surprised if it turns out to work as it is. It would be desirable though to be able to move the sail about 20cm forward. One way is to make the mast step as a short slot, so that the mast can be raked 1-2° forward, if needed.

I also wonder about the rudder. To me it looks to be on the small side. How does it work today? What about ‘filling in’ that lower corner and then add an endplate to it? I have received reports that an endplate increases the efficiency of their rudders.

I think I will draw another junk sail, almost the same as shown here, but with the yard angle lowered to 55°. This will allow you to increase the mast balance past 26%. Just remember, I don’t have practical experience with this high mast balance. At one point, the sail may decide to become unstable and not feather correctly. However, I am quite confident that the sail ill behave itself with 25% balance. The mast will rob some camber at the port tack, but one cannot have it all. At least I know that this mast effect hardly is noticeable with 22% mast balance.

Arne

(See Arne's sketches section 7, photo 16)

Thanks for sending both rig ideas.

Interesting that you picked up on the rudder. I drew it that shape because I liked the look of it. The more I read I realised a squared shape is much more efficient and it ended up very similar to the one you sketched!

I can't claim to have built the whole boat as I worked as a tutor with Master Shipwright Bill Foster and we built her with nine students in Tasmania launching in 98.

Jim, first of all, hats off for you!
Only now did I realise that you have both designed and built your boat. I could never do that.

Now I have plonked my suggested sail with 60° yard on top of your sailplan with a gaffrig (GR). As you can see, the lead of the JR is much shorter than that of the GR. Still, I would not be surprised if it turns out to work as it is. It would be desirable though to be able to move the sail about 20cm forward. One way is to make the mast step as a short slot, so that the mast can be raked 1-2° forward, if needed.

I also wonder about the rudder. To me it looks to be on the small side. How does it work today? What about ‘filling in’ that lower corner and then add an endplate to it? I have received reports that an endplate increases the efficiency of their rudders.

I think I will draw another junk sail, almost the same as shown here, but with the yard angle lowered to 55°. This will allow you to increase the mast balance past 26%. Just remember, I don’t have practical experience with this high mast balance. At one point, the sail may decide to become unstable and not feather correctly. However, I am quite confident that the sail ill behave itself with 25% balance. The mast will rob some camber at the port tack, but one cannot have it all. At least I know that this mast effect hardly is noticeable with 22% mast balance.

Arne

(See Arne's sketches section 7, photo 16)

Anonymous wrote:

Jim wrote:

Thank you David for your advice.

Yes weight of sail and battens will be an issue. I hope to use carbon battens and a lightish to medium weight cloth. Would you recommend a weight and perhaps a manufacturer. I don't mind paying a bit extra for something that will last and be UV stable.

When we sailed back from Oz we cruised in company for a while with a Hereshoff cat ketch called Pollen Path. The unstayed masts were layers of glass over hollow spars. Randy complained that they were a bit whippy at the mast head but they must have been strong as she survived the Queen's Birthday Storm, when many were lost.

Talking of old cruising friends, I wonder if anyone has heard of someone we met. I think his name was Roger and he had a green junk rigged steel Tahiti ketch called Irene. He sailed single handed and I was very impressed watching him thread his way through the reefs in Tonga. He was also a very nice chap.

Thanks again, Jim 

It's not only about rig weight. It's also about manageability in difficult conditions - gybing a big low AR sail is not for the faint-hearted.

Top Gun 9 would be a good choice of cloth.

Flexible unstayed masts are unpleasant to sail with. Please don't use glass except as a thin sheathing layer over wood, to protect against abrasion. Its strength/weight and stiffness/weight ratios make it a poor choice for the structure. For your wooden boat, a wooden mast is the obvious choice. 

I met Roger and Irene in the R Guadiana, between Portugal and Spain, on my way south in 2006, but your meeting is probably more recent.

How interesting that you met Roger. Our paths crossed in 2000.

The thin walled inner wood mast is really just a mold to wrap many layers of glass and carbon round to make a very stiff very strong mast. I wonder if any members have tried this combination.

Progress so far: stripped out the forward cabin . Will clean and paint then fit two more floors and then fit a 4 foot 6 mast step over the top of the then 6 floors which will also joint onto the end of the existing mast step. Other work will be altering the fore deck structure to take the partners. The Douglas fir arrives next week but we won't start construction till July.

Thanks for the sail cloth into.

Jim wrote:

Thank you David for your advice.

Yes weight of sail and battens will be an issue. I hope to use carbon battens and a lightish to medium weight cloth. Would you recommend a weight and perhaps a manufacturer. I don't mind paying a bit extra for something that will last and be UV stable.

When we sailed back from Oz we cruised in company for a while with a Hereshoff cat ketch called Pollen Path. The unstayed masts were layers of glass over hollow spars. Randy complained that they were a bit whippy at the mast head but they must have been strong as she survived the Queen's Birthday Storm, when many were lost.

Talking of old cruising friends, I wonder if anyone has heard of someone we met. I think his name was Roger and he had a green junk rigged steel Tahiti ketch called Irene. He sailed single handed and I was very impressed watching him thread his way through the reefs in Tonga. He was also a very nice chap.

Thanks again, Jim 

It's not only about rig weight. It's also about manageability in difficult conditions - gybing a big low AR sail is not for the faint-hearted.

Top Gun 9 would be a good choice of cloth.

Flexible unstayed masts are unpleasant to sail with. Please don't use glass except as a thin sheathing layer over wood, to protect against abrasion. Its strength/weight and stiffness/weight ratios make it a poor choice for the structure. For your wooden boat, a wooden mast is the obvious choice. 

I met Roger and Irene in the R Guadiana, between Portugal and Spain, on my way south in 2006, but your meeting is probably more recent.