The Lutra Laker Design by David Nichols

[usedfilm]

Hi there,

I have been hoping that someone can help me. I would like to build the above boat. I need help build her, please see attchment "OFFSET" can someone give me an insight on how to read this.

Originally Posted by usedfilm

Hi there,

I have been hoping that someone can help me. I would like to build the above boat. I need help build her, please see attchment "OFFSET" can someone give me an insight on how to read this.

A table of offsets describes the position of a point on a frame. When you draw these positions on a paper or shop floor, then connect them in a smooth line, you get the shape of the frame.

Thats it in short.

Regards
Richard

[usedfilm]

Thats the short version! Now how about the long version if thats possible?

Oh no please,

lets wait for some native English speaker to chime in here. I would need 30 minutes to describe what our English speaking NA´s do in one.

[usedfilm]

Thats no possible? Lets hope some one will help me out.

Thank you

[daiquiri]

I am not a native english speaker, but let me give it a try.

The table of offsets you have here is basically a table of X-Y-Z coordinates of points which describe the form of boat's sheer, upper and lower chines and the keel, in imperial units.
The coordinates are given as:
X = station position (#1, #2, #3, etc. to the transom)
Y = half-breadth value
Z = height value

Y and Z are given as 3 numbers each, in the form A-B-C which rappresent:
A = feet
B = inches
C = 1/8th of an inch.

For example, at 1st station the sheer line has a following coordinate:
1-11-5 height and
0-6-1 half-breadth,
which means
1 ft, 11 in, 5/8 in. of height
0 ft, 6 in, 1/8 in. of half-breadth.
Translated to the metric system it becomes:
0.600 m (600 mm) height, 0.156 m (156 mm) half-breadth.

So, by connecting these points (sheer, u. chine, l. chine and keel) at a given station, you get the shape of the transverse section of the hull, which allows you to construct the frame for that station.

Traditionally, the table of offsets was given for the outside skin of the hull, so one would need to detract planking thickness in order to obtain the net frame coordinates.
In this case, the reading at the bottom says that this table of offsets is for the inside of the hull, so no detractions are necessary.

I am including an xls file with the table of offsets of your hull in both imperial and metric units. It took me 10 minutes to create it. Maybe if you see the coordinates in decimal (metric) units, the things will become more clear for you.

Cheers!

[usedfilm]

Thank you for the info, I will now try to set out one of the station HB1 and I will see how I get on.

Thanks Slavi!

[dustycrockett]

does this help?
[note that the station number 5 label is actually at station #6 -- that is not new math or anything, just a mistake. sorry bout that]

[usedfilm]

dustycrockett

It sound like you have I built this boat yourself?

[Lurvio]

Hi

You also need the offsets for the stem, as it is missing from the table you posted.

I decoded the offsets in cad, they should look something like this.

click for full size

The purple lines are centerline and bottom.

Edit:
I've been looking at my own scribble too long to remember others have to understand them.

Lines are from left, Stations 6-8 and transom and right side has (from center) Stations 1-5.

Lurvio

[Lurvio]

Also this might help.

Duckworksmagazine

[dustycrockett]

Originally Posted by usedfilm

dustycrockett

It sound like you have I built this boat yourself?

No, I've not built any boats, yet, but plan to start...soon. Been researching the subject for awhile, I've got a lot good info from the forum so thought I might contribute where I could.

here I've used daiquiri's spreadsheet to plot your first station:

[usedfilm]

dustycrockett,

Thank you for all this info, I have had no luck at taking the sizes off the OFFSET and putting them onto paper, but I hope that by next weekend I will have got some insight into the work's? At the moment I am still trying to get a roof over the workshop, I hope by to night I will have finished!

[thedutchtouch]

that boat reminds me of a square stern canoe/ gheenoe... what's the Length overall?