Originally Posted by stevedonna
Hmmm I think I know which one you were in my class at school .
Oy! We can't all be hunky sportsmen you know...
My thoughts now are that I need to know what depth I will be dropping the pots in before I set them up , then I need to use the rope in a way that means I can alter it next time . I thought at first I would set the pot to pot rope up as a one off but clearly not as it will alter . So if I use weights on the pot to pot rope they will need to be movable .
I am thinking one length of rope through all three pots . So it's reusable next time , if that makes sense
That makes sense to me. I'd be tempted to have my weights on a simple carabener and then a quick bight in the line where you want it and clip it on. When you are finished unclip and store weights in a bucket and rope will coil tidy again.
I've tried to draw out what I described earlier as I'm not sure how clear it was.
Figure 1a shows the effect of the depth on the distance between pots, 1b shows what happens if there is no weight on the between pots rope. 2a Was what I described earlier of a weight on the between pots line.
2b is a new problem for you! there was mention of 15ft down placing the weight. I think if you drop that in 20ft of water and the tide drops by 10ft the weight will be sat on the bottom with 15ft of loose line above it.which means about 5ft is spare, Thats 5ft of line that may be close to your prop on retrieval. So I think the weight needs to move. That got me thinking mathematically what that might look like and I came up with a few equations:
The data you need (in my opinion) is:
dmax - the maximum water depth you will be setting in at maximum tide height
dmin - the minimum water depth that you would expect the tide to drop to over your creels
C - the length of rope you plan to put between our creels (yes I've seen the above - but that does mean more buoys doesn't it!)
P - the distance below the water that you expect a propeller to be and so the distance you want any floating rope to be
dset - the depth you are setting in.
Once you have all of that, you need to decide how long your buoy to creel rope (B) will be. It must be greater than or equal to dmax.
Then you can work through the numbers - dmin will tell you where to put the weight. You may need a second weight if the answer is less than B you do.
Then calculate H and L. I suspect L will almost always be about 1/2 of C.
dmax and dmin are probably relatively difficult to know but if you are looking at a chart and thinking I wouldn't want to go any shallower than here - that will give you your dmin once you calculate out for tide heights. And the same for dmax - where is the furthest out you might go? Adjust that for high tide and make that dmax.
So then that only leaves dset. As you'll see its only used to calculate H and probably not that crucial...I'd suggest calculating the tide height for the spot height you used for dmax and dmin at roughly the time you plan to set them and see what it looks like as an answer.
I'm pretty sure someone will be along in a minute to say the pro's have never used an equation in their lives. But I suspect they may learn the results that the equation might give...