@OldieNewbie
Hi OldieNewbie, It would actually be helpful to know which model ship you are building.
The challenges vary significantly from one model to another.
For instance, a modern sloop (as opposed to a faithful scale replica of a historic vessel) doesn't prioritize aesthetics; everything is designed for RC sailing functionality, resulting in a minimalist, stripped-down exterior. Crucially, there is no need to hide control linkages or running rigging; these can remain fully visible on deck and be oversized to maximize functionality.
By "sloop," I refer to boats with a single mast, a jib, and a mainsail, typically characterized by a very deep bulb keel.
These vessels always feature triangular sails (such as Marconi or Bermudian rigs) and a jib.
As far as I know, there are two main ways to control a sail sheet: using a drum winch or using a servo with a control arm (similar to a rudder servo).
The first option (the winch) rotates a spool around which the sheet is wound. The second moves an arm to pull in or release the sheet.
Given equal electric motor power and gearing, the first option (drum winch) generates greater torque.
You could increase pulling force by creating leverage through a pulley system (much like block-and-tackle winches), but I strongly advise against this, as you would likely face major issues with tangled lines.
This factor can be important—even decisive—if you are using a servo with an arm to control a large sail area; if the servo lacks sufficient power, it will burn out.
With the servo-arm system, the sheet's range of movement is minimal (certainly less than with a drum winch), yet it is often sufficient to move the boom from a close-hauled position (sheet fully sheeted in) to a broad reach (sheet fully eased out). With a drum winch system, you can take up a long length of sheet (I’ve managed up to 36 cm); in fact, winches are available on the market with two, four, or six turns.
In the end, I actually faced the opposite problem: I had too much line to manage—far less was needed.
At this point, I’ll offer a piece of general advice that always applies. First, you need to determine—either through a practical test, as Ross does, or by using a diagram—the total sheet travel between the maximum (fully eased) and minimum (fully sheeted-in) positions, and then select the most suitable winch based on that measurement.
An arm-type servo system requires more space below deck than a drum winch system, as the arm needs to be reasonably long and must rotate through 90 degrees.
When I first tackled this problem, I had neither examples nor points of reference—aside from fast racing boats (the sloops I mentioned earlier), which weren't suitable for my needs.
I had to control two mainsails and their corresponding gaff sails (meaning I was operating two booms) as well as two schooner-style headsails.
Square sails are easier to control because, using a drum winch, you can rotate the yardarm by using two sheets on the same winch—one is wound in while the other is let out, and vice versa—creating a closed-loop system.
This system wasn't suitable for gaff sails; if controlled in a similar way, they would be limited to a fixed range of motion to the left or right. Instead, the angle needs to vary—from the minimum required for close-hauled sailing to the maximum needed for broad reaching or running downwind.
A drum winch setup can operate as a closed loop (a line running through pulleys), with the various sheets attached to this continuous loop of moving line.
Alternatively, the sheet can be wound directly onto the drum; in this case, the motor provides the pulling force (winding in), but the unwinding action relies solely on the wind pushing the sail open.
Ultimately, lacking existing references, I chose an open system, which you can see in the attached videos and links:
The sheet starts fully extended (for broad reaching) and can be reeled in by commanding the winch to rotate in one direction, shortening the line to its minimum length (for close-hauled sailing).
When it is time to return to a beam reach or broad reach, the drum is commanded to rotate in reverse; however, the force pulling the sheet and unwinding it from the drum comes from the wind acting on the sail and pushing it outward.
I don't believe this is the best system, and I am still looking for a viable alternative. For now, I’ve put this on hold to focus on planing hulls, though I still keep an eye out for interesting projects like Ross’s.
I don’t think my system is 100% effective, as it struggles with tacking in light winds (where there is little momentum).
Racing boats—even those using standard servo arms—are highly efficient when tacking; this is due to their specific trim, but above all, their massive, effective rudders. In contrast, the rudders on scale models tend to be small and ineffective for tacking or low-speed maneuvering.
Later on, systems appeared that I could have replicated—such as those used on the Robbe Valdivia and Gary Webb’s models.
Both are solid, functional systems (though the Robbe Valdivia’s is perhaps a bit overly complex), yet neither solves the issue of easing the sheet; in that phase, the force required still relies on the wind acting on the sail.
https://model-boats.com/forum/169185
https://model-boats.com/forum/128542
Hi OldieNewbie, It would actually be helpful to know which model ship you are building.
The challenges vary significantly from one model to another.
For instance, a modern sloop (as opposed to a faithful scale replica of a historic vessel) doesn't prioritize aesthetics; everything is designed for RC sailing functionality, resulting in a minimalist, stripped-down exterior. Crucially, there is no need to hide control linkages or running rigging; these can remain fully visible on deck and be oversized to maximize functionality.
By "sloop," I refer to boats with a single mast, a jib, and a mainsail, typically characterized by a very deep bulb keel.
These vessels always feature triangular sails (such as Marconi or Bermudian rigs) and a jib.
As far as I know, there are two main ways to control a sail sheet: using a drum winch or using a servo with a control arm (similar to a rudder servo).
The first option (the winch) rotates a spool around which the sheet is wound. The second moves an arm to pull in or release the sheet.
Given equal electric motor power and gearing, the first option (drum winch) generates greater torque.
You could increase pulling force by creating leverage through a pulley system (much like block-and-tackle winches), but I strongly advise against this, as you would likely face major issues with tangled lines.
This factor can be important—even decisive—if you are using a servo with an arm to control a large sail area; if the servo lacks sufficient power, it will burn out.
With the servo-arm system, the sheet's range of movement is minimal (certainly less than with a drum winch), yet it is often sufficient to move the boom from a close-hauled position (sheet fully sheeted in) to a broad reach (sheet fully eased out). With a drum winch system, you can take up a long length of sheet (I’ve managed up to 36 cm); in fact, winches are available on the market with two, four, or six turns.
In the end, I actually faced the opposite problem: I had too much line to manage—far less was needed.
At this point, I’ll offer a piece of general advice that always applies. First, you need to determine—either through a practical test, as Ross does, or by using a diagram—the total sheet travel between the maximum (fully eased) and minimum (fully sheeted-in) positions, and then select the most suitable winch based on that measurement.
An arm-type servo system requires more space below deck than a drum winch system, as the arm needs to be reasonably long and must rotate through 90 degrees.
When I first tackled this problem, I had neither examples nor points of reference—aside from fast racing boats (the sloops I mentioned earlier), which weren't suitable for my needs.
I had to control two mainsails and their corresponding gaff sails (meaning I was operating two booms) as well as two schooner-style headsails.
Square sails are easier to control because, using a drum winch, you can rotate the yardarm by using two sheets on the same winch—one is wound in while the other is let out, and vice versa—creating a closed-loop system.
This system wasn't suitable for gaff sails; if controlled in a similar way, they would be limited to a fixed range of motion to the left or right. Instead, the angle needs to vary—from the minimum required for close-hauled sailing to the maximum needed for broad reaching or running downwind.
A drum winch setup can operate as a closed loop (a line running through pulleys), with the various sheets attached to this continuous loop of moving line.
Alternatively, the sheet can be wound directly onto the drum; in this case, the motor provides the pulling force (winding in), but the unwinding action relies solely on the wind pushing the sail open.
Ultimately, lacking existing references, I chose an open system, which you can see in the attached videos and links:
The sheet starts fully extended (for broad reaching) and can be reeled in by commanding the winch to rotate in one direction, shortening the line to its minimum length (for close-hauled sailing).
When it is time to return to a beam reach or broad reach, the drum is commanded to rotate in reverse; however, the force pulling the sheet and unwinding it from the drum comes from the wind acting on the sail and pushing it outward.
I don't believe this is the best system, and I am still looking for a viable alternative. For now, I’ve put this on hold to focus on planing hulls, though I still keep an eye out for interesting projects like Ross’s.
I don’t think my system is 100% effective, as it struggles with tacking in light winds (where there is little momentum).
Racing boats—even those using standard servo arms—are highly efficient when tacking; this is due to their specific trim, but above all, their massive, effective rudders. In contrast, the rudders on scale models tend to be small and ineffective for tacking or low-speed maneuvering.
Later on, systems appeared that I could have replicated—such as those used on the Robbe Valdivia and Gary Webb’s models.
Both are solid, functional systems (though the Robbe Valdivia’s is perhaps a bit overly complex), yet neither solves the issue of easing the sheet; in that phase, the force required still relies on the wind acting on the sail.
https://model-boats.com/forum/169185
https://model-boats.com/forum/128542