FS18 Station "A" dimension question...

[Bayport_Bob]

Hi Jacques,

Pete44 pointed this out on another thread, but I figured it would be more visible in a new thread...

For the FS18, on drawing D279/3 "Stations & Lines"

Station A appears to be missing distance above the baseline for the side panel. Stations D & E show this dimension, but it appears to be missing for Station A.

Thanks! - Bob

[mikebro72]

dude...the panel dimension doesnt change(frame stays the same, deck sits on this... ).....you cut the panel according to the drawing on the "plates" page....that will give you the amount above the baseline at station a, and everything else......if you are doing the flush deck version, you use those dimensions.....

[Bayport_Bob]

Dude,

You need this dimension to accurately lay out Frame A. Take a look at Frame E and you'll see what I mean. If you just use the top of the side panel dimension on E as the top corner of the frame, then your frame will be too wide at the top by 3/8 to 1/2" overall.

We're talking Frame layout, not side panels.

[Super Spook]

Good call Bob. When I cut the panels for my model I used the 14 3/8" for the width measurement at the baseline. This might explain why frame A doesn't quite fit on my model. Just to confirm, frame A should not extend above the baseline, as the deck rests on top of it, right? Is this not the case with the designed sheer line version?

[Bayport_Bob]

The total depth of Frame A should be 17.125"


This post was edited to remove incorrect dimension information. Please read the replies below!

[jacquesmm]

Let's remove the confusion: all the stations are measured from the baseline and the baseline is the upper face of the deck. when on the jig, that means upside down.
The stations drawing says upper face but shows the boat right side up. That is not consistent. I will either flip the view or change the text to say "lower face of deck with boat afloat" or "upper face of deck when on buidling jig".
When you look at the picture of the jig in the building notes, it makes sense: all the frames ( = stations) sit on the deck and gunwale surface and that is the plane from which we measure everything.

Those who have subtracted the thickness of the deck should have no problem: their deck will now be 3/8" lower in theory but in theory only.
It will still work because after fiberglassing the inside they must adjust the depth of the frames. With the fiberglass thickness, the frames will be within 1/8" of the sheer. And if you need a little piece of foam under it to raise it 1/4", do it, it is better than direct contact of the frame with hull.
This applies to the straight sheer version too.


For Mikebro: you are correct. You interpreted correctly my misleading note on the plans.

For Bayport Bob: It is not missing, the frame does not extend above the deck. I don't know why I showed it for E, I will remove that dimension, you don't need it.

[jacquesmm]

I went back to the office on Sunday afternoon to check that.
I knew there is something wrong when experienced builders disagree on something on the plans.

[Bayport_Bob]

Thanks Jacques, that clears up my incorrect interpretation. No problem on the 3/8", it only impacts 3 of my stations - A, B, & E. They were already cut by Wood Butcher Bob. I can easily shim them like you mentioned.

[pete44]

Jacques,

...the frame does not extend above the deck. I don't know why I showed it for E, I will remove that dimension, you don't need it.

Since I was originally responsible for the missing dimension post, I would like to suggest my theory on why there are above BL dimensions on stations E, C2, D, and transom. First, the height of each of these dimensions seems to visually match the space between the BL and sheer on the side view. Second, the lack of these dimensions on stations B and C also correspond to the foreshortened heights of these stations on the side view (bold lines not touching the sheer). This seems to indicate that these dimensions represent points along the sheer line.

If my theory is correct, a dimension for the height above BL for the sheer point on station A — just like the ones on the other 4 stations — is still needed. I assume these dimensions are automatically generated by the software you use, so I hope I am being helpful in pointing out what I feel are inconsistencies.

Thanks for such a well designed boat,
Pete

[jacquesmm]

You don't need a dimension for the sheer, the frame stops at the deck.
To add a dimension that we can't use would only confuse builders.

If I was producing traditional lines, you would be correct: it is impossible to loft the sheer the traditional way without that dimension but since we do not loft, I prefer to keep it simple.