Net Skiff Build:sheer line curve
Posted: Wed Feb 22, 2012 2:40 pm
netman, boat building is a series of decisions so how about thinking about one that is not crucial for the time being?
The sheer. This can be a curve or a line in profile but in 3D or as-built will always be some form of curve on the skiff you've proposed to build.
This curve is not critical to the bottom decisions that are immediately ahead but since it will affect the skiff's build and you'll have to draw this line in the not distant future let's begin introducing this curve as a way to further discuss the subject of curves?
here is a look at the 'example' skiff that I've been using to illustrate the lines and curves posts so far. The sheer is a line in profile/side view and lots of boats use this sheer.
same skiff shape with a hollow or 'traditional' sheer that is a long slow sweet curve bow to stern/transom top.
and the powder horn or Western sheer as some refer to this set of two curves at the sheer line. I've used this shape extensively since the 'flattening' forward allows the tank top surface to be less inclined to the waterline and therefore less work to lay over when working the waterline below the sheer in the forward 1/3 of the hull.
The line not shown is the opposite of the second example above where some speed boats' sheer is a long bulging curve what becomes most attractive when the boat is running. Then that particular sheerline become flat in the forward 1/3 and the curve when pitched up by the bow a few degrees then has a rising line instead of 'hump back' shape. ( I didn't illustrate this shape as its not that functional for net skiffs and is usually used for the higher speed boat running slightly pitched up by the bow.)
Each of the sheerline types can be drawn on the net skiff but the choice mainly aesthetic; therefore a personal taste issue is one that needs its own consideration. I know fishermen who will not own a boat with each of these lines! So this choice is ahead and should have some consideration, and it works to give some good practice drafting curves to look at these lines in different proportions (the curves at least) and draw some variations in order to see which is most appealing.
[ Pop Quiz ! : can you spot the 'hog' or unfair point in each of these three profile views? I used a PC with SketchUP to draw these- not a hull modeling marine software suite. That has left a 'legacy flaw' from the method/type/order of tool use I employed to create these sketches, but this does illustrate a curve's flaw pretty clearly.]
Cheers,
Kevin Morin
The sheer. This can be a curve or a line in profile but in 3D or as-built will always be some form of curve on the skiff you've proposed to build.
This curve is not critical to the bottom decisions that are immediately ahead but since it will affect the skiff's build and you'll have to draw this line in the not distant future let's begin introducing this curve as a way to further discuss the subject of curves?
here is a look at the 'example' skiff that I've been using to illustrate the lines and curves posts so far. The sheer is a line in profile/side view and lots of boats use this sheer.
same skiff shape with a hollow or 'traditional' sheer that is a long slow sweet curve bow to stern/transom top.
and the powder horn or Western sheer as some refer to this set of two curves at the sheer line. I've used this shape extensively since the 'flattening' forward allows the tank top surface to be less inclined to the waterline and therefore less work to lay over when working the waterline below the sheer in the forward 1/3 of the hull.
The line not shown is the opposite of the second example above where some speed boats' sheer is a long bulging curve what becomes most attractive when the boat is running. Then that particular sheerline become flat in the forward 1/3 and the curve when pitched up by the bow a few degrees then has a rising line instead of 'hump back' shape. ( I didn't illustrate this shape as its not that functional for net skiffs and is usually used for the higher speed boat running slightly pitched up by the bow.)
Each of the sheerline types can be drawn on the net skiff but the choice mainly aesthetic; therefore a personal taste issue is one that needs its own consideration. I know fishermen who will not own a boat with each of these lines! So this choice is ahead and should have some consideration, and it works to give some good practice drafting curves to look at these lines in different proportions (the curves at least) and draw some variations in order to see which is most appealing.
[ Pop Quiz ! : can you spot the 'hog' or unfair point in each of these three profile views? I used a PC with SketchUP to draw these- not a hull modeling marine software suite. That has left a 'legacy flaw' from the method/type/order of tool use I employed to create these sketches, but this does illustrate a curve's flaw pretty clearly.]
Cheers,
Kevin Morin