Thread: Dana's Spars

No mistake on your part Clint.

I had the "A" Measurement taken across the guides rather than to the centreline as per the drawing.

Now corrected with the drawing below. I will send an plan update to my agents. Will check other drawings too. A while ago Theodor pointed an error out in my oar plan spar gauge .. this is another one I think or same one in another place.

MIK

Spars: Done. I will bring up some questions about spar bend in a few days.

AND a weight for the birdsmouth mast too would be great.

There is nothing like data!

MIK

I asked because the yard seemed flexi. I should have taken some measurements. Maybe on the next set. Is there a pounds per inch of flex target I would be looking to achieve? or is it subjective like with oars. I did build them with Spruce, but bumped up the diameter by 2mm overall on yard and boom (since Spruce is not as stiff as Oregon). I'll measure the box mast. I guess I could do the same with the spars with the sail laced up.

Clint

Howdy Clint,

If you kept to the taper plan plus that little bit you added it will be fine.

There is probably an idealish type of flex per kilo but it would take a lot of sailing trials to work it out. And it would be different with different crew weights etc.

If someone is keen to work that out they will probably need more than one goat in their area to do careful comparison sailing against.

Racing dinghy sailors know the advantages of getting some flex in the yard and a lesser amount in the boom. But that flex will make the boat accelerate when a gust hits rather than be hard to hold up. The unknown is the spruce is less dense, so more bendy, but you have compensated.

I guess sailing trials will be proof of the pudding.

MIK

Did some sailing in Dana's skiff today. We had fun, my wife and I and all of Dana's gizmos (electric trolling motor, battery, bilge pump, anchor and the kitchen sink). Wind was light, about 5-10 kts.

I wish I remember my camera because I have some observations and questions:

1) there is a wrinkle from the heel of the yard down to the lower batten about midway fore and aft.
2) the sail leech flutters a bit above the top batten...the yard seems to bend quite a bit up there, as well.
3) the yard doesn't want to stay lying against the mast and it occurred to me that the yard halyard block was a little to low. I also noticed there is quite a bit of mast above the yard so the halyard can swing away from the mast a few inches. If the yard were tight up to the deadeye at the masthead it would help the problem.
4) In the lightish winds I hardly sat on the rail but my tall frame wanted a little seat to sit on inside the boat. I was thinking a folding seat would be nifty, one that could move from port to stbd and be a seat for the helmsman inside the boat.

#3 brings me to my questions: I have some Sitka spruce that I wish to use with my northern whote spruce staves for the b'mouth mast. Problem is the sitka board is 15'2". Why bother scarfing more on...there seems to be enough mast length...would I make things worse by shortening the mast up to 15'2", about 4" less than designed? I could prop the mast step up an inch to compensate?

Any thoughts on the observations? I may go back out to play some more. Thanks.

Clint

The 15' 6" mast gives you some flexibility in setting it up. You probably recall the photos of Gruff on her maiden voyage with the boom set too low. MIK corrected that in subsequent revisions. The point being the clearance of the boom above the gunwale is quite generous in the current plans, so with a few other tweaks you should be able to make it work.

After rigging mine for the first time I wondered about the extra length as well, but mainly because a shorter mast could be stored 100% inside the hull.

At 15' 2" you will be giving up most of the flexibility in the rigging but if you shove the dead-eye at the top as high as you can go and raise the foot a half inch or so (anything you do at the base will have a dramatic affect on the stresses at the partner but you already know that) it would probably work. You would also end up with a spar that stores inside.

How far down from the tip do you guys recommend attaching the halyard block / deadeye?

Originally Posted by Compass Project

4) In the lightish winds I hardly sat on the rail but my tall frame wanted a little seat to sit on inside the boat. I was thinking a folding seat would be nifty, one that could move from port to stbd and be a seat for the helmsman inside the boat.

#3 brings me to my questions: I have some Sitka spruce that I wish to use with my northern whote spruce staves for the b'mouth mast. Problem is the sitka board is 15'2". Why bother scarfing more on...there seems to be enough mast length...would I make things worse by shortening the mast up to 15'2", about 4" less than designed? I could prop the mast step up an inch to compensate?

A side seat would be really nice. How about something built in between the middle thwart and the back seat on each side of the boat? This seems to be the spot I would spend my time while sailing with my wife. When sailing alone I use the middle seat.

As for shortening the mast, I have no idea how that would affect the boat, but I kind of wish my mast was a bit longer just so I could have more clearance for passengers heads under the boom.

Originally Posted by Compass Project

Did some sailing in Dana's skiff today. We had fun, my wife and I and all of Dana's gizmos (electric trolling motor, battery, bilge pump, anchor and the kitchen sink). Wind was light, about 5-10 kts.

I wish I remember my camera because I have some observations and questions:

1) there is a wrinkle from the heel of the yard down to the lower batten about midway fore and aft.

Could be the halyard block in not quite the right place or the bottom batten is too stiff or tied in too tight or not enough downhaul tension.

2) the sail leech flutters a bit above the top batten...the yard seems to bend quite a bit up there, as well.

Does there seem to be reasonable hollow in the leach. You could check by using a stringline from peak to clew.

3) the yard doesn't want to stay lying against the mast and it occurred to me that the yard halyard block was a little to low. I also noticed there is quite a bit of mast above the yard so the halyard can swing away from the mast a few inches. If the yard were tight up to the deadeye at the masthead it would help the problem.

The mast should be trapped between the yard and the halyard. With all of my boats the yard is held against the mast with considerable force. The halyard goes from the masthead to the block at the mid point of the yard. Then it goes up to the front end of the yard ON THE OPPOSITE SIDE OF THE MAST FROM THE YARD. Could be inadequate downhaul tension also which would also explain the crease mentioned above.

4) In the lightish winds I hardly sat on the rail but my tall frame wanted a little seat to sit on inside the boat. I was thinking a folding seat would be nifty, one that could move from port to stbd and be a seat for the helmsman inside the boat.

I have used a plastic icebox, but normally if alone I am on the mid seat. With someone else there they can sit to leeward on the mid seat and then usually it is possible to sit on the gunwale.

#3 brings me to my questions: I have some Sitka spruce that I wish to use with my northern whote spruce staves for the b'mouth mast. Problem is the sitka board is 15'2". Why bother scarfing more on...there seems to be enough mast length...would I make things worse by shortening the mast up to 15'2", about 4" less than designed? I could prop the mast step up an inch to compensate?

It think it would make the length a bit marginal. On some Goats the yard ends up very close to the top of the mast.

Hope this helps
MIK

Thanks, I will check those things. And I will scarf on the wood I need to get ful length stave and not be so lazy.

I FORGOT! to mention the best part of our outing. We took a 420! We have a lot of 420's racing in the harbor and we totally caught up to one, ate him right up, on a close reach. My wife was impressed as were they! He even tried to tack onto me and give me bad air and it didn't work.

I was grinning ear to ear.

Dana should be proud of his work on this boat and Mik for his clever design. Whoever made those spars, they look pretty good too

Clint