AD 14, question for Jacques

[bondo]

As I said, I think the pattern is the problem. As I told Gonandkarl, the designer will say everything is ok.

[gonandkarl]

Hallo Jacques and Bondo,
Thank you very much for the extensive discussion about the small centerboard problems I have.
I can fit the centerboard to fit the trunk if I follow Bondos advice of the right angle at the top of the case and then I can keep the tip of the board 20 mm ( 3/8 ") away from the trunk. This is neccesary for the thickness of the batten between the trunk sides. The tip can also slightly be rounded like I have seen on pictures of Bondo s board and then it will not hit frame C.
The full size pattern of the board is due to slight printer adjustments to short and the trunk height measurements (448 and 226) of plan B264/8 over the calculated lenght of 757 mm ( = 1655 - 356 - 542 ) produce a different angle than the centerboard
top. One would not have to rely on the fullsize plan of the board if the height measurement opposite "322" would be on the plan.
( B264/8)
Coming to a conclusion I must say that your discussion has helped me and the last picture of Jacques helps also a lot because it contains a trunk measurement from frame B and it shows fine how it must look in the end. Thanks very much and
Greetings from Karl (Austria)

[jacquesmm]

OK then. I will:
- check each batch of full size patterns
- write a warning notice about their use in the notes: check a dimension before use.
- add that missing dimension to the CB drawing so that builder's don;t have to rely on the patterns.

[bondo]

That would be great Jacques. Also, take a pen and cross out 2 degrees at the mast rake drawing, write 5 degrees next to it. Gonandkarl, I will answer more of your questions if I can. The white template centerboard was how I dialed in the locking holes on the centerboard. The centerboard pivot details are incorrect. (be patient as there are no other problems after this) The ss tube is the pivot. The tube goes right through from the outside of the trunk. The centerboard bears on the tube. The tube rests on the trunk sides. The bolt through the tube slightly tightens washers against the trunk sides. Squeezing plumbers putty against the trunk sides. (but not able to over tighten/with the washers stopped against the tube) in this way you can tighten the assembly without distorting the trunk sides. I will try more later.

[gonandkarl]

Hallo Bondo,
Thanks very much for the pivot explanation which brings me to another question.
The picture of your pivot assembly shows the Delrin squares as if it consists of 3 parts. Did you fit on the middle plywood part of the centerboard a smaller square of Delrin plastic so that it funtions the same way as the bigger hole for the lead which holds the outer lead just that here the plywood is holding the delrin from shifting sideways ?
If that is so how did you glew the 3 delrin pieces together and did you install the delrin before laminating the centerboard ?
Greetings from Karl (Austria)

[SP]

I know this is an old thread, but I have a question and maybe this is the issue.

How do you locate the bow end of the center board case (226mm) from the drawing posted by Jacques?

The drawing tells you how tall the case is (226mm) but there is no height measurements to locate it, only fore and aft measurement of 1654mm.


Maybe the picture posted is not the complete dim. drawing of the part?

[gonandkarl]

Hallo SP,

You can find this on the plan D264_03 Constuction and Lamination : It is 408 mm from station B in the direction to the front bow bow.
On plan D264_04 Stations You can find the exact position of station B from the bow.

Greetings from Karl ( Austria )

[SP]

Hi,

My question is about when laying out and building the center board case itself.

[gonandkarl]

Hallo SP,

I built my centreboard case the correct lenght 1654 and 226 high and with 2 battens (18 mm) on each end which reduces the length of 1654. These battens in my case are 18mm by 50 mm.

The problem with Jaques plan is, that with his supplied measurements of the case You wont get a 90 degree angle on the frame C going forward. This is according to Bondo important and therefore I made sure I achieved this 90 degree angle with the result that the longish top line of the centreboard case is different to the plan.

Hopefully this will help You.
Greetings Karl ( Austria )

[SP]

When I look at the drawing of the case, the bottom front and rear (226 and 448 measurements) do not appear to be on the same axis. If this is the situation then we need another measurement to find out where exactly the front of the case is vertically. Also, if this is true, then maybe it explains why people are having issues with the case. Maybe they are drawing it as if the bottom of 226 and 448 are on the same axis.

Here is a drawing, not to scale, showing what I am trying to explain.

What is the measurement from the X-axis to the bottom of the 226 measurement?




Jacques posted pic for reference.