New Windlass - Questions

[Steve Bean]

I've just done some reading on buoyancy. Everything has some of it, even metals. Iron, for example, when submerged in fresh water, weighs only 85 percent of its dry weight. In salt water, even a little less. So sizing the windlass according to the dry weight of the anchor and chain will result in a safety margin of about 15 percent.

[steve77]

Originally Posted by a64pilot

I think to size a windlass weight of the anchor and chain isn’t really all that relevant. Or said another way a windlass that is sized to only lift the anchor and chain may not be enough windlass.
I have a 40 Kg Rocna and 5/16” chain.
My VWC 1500 will easily raise the anchor and over 100’ of chain. I have not had the anchor down in deeper water.
However in 10’ of water with a heaping shovel full of mud if you will, raising the anchor strains it. It comes up, but you can tell it’s working to do it.

All of the manufacturers have a method of sizing the windlass based on weight of the ground tackle. It involves adding up all of the weight to be lifted and then multiplying by 3 or 4 (depending on the manufacturer). This multiplier is there for a lot of reasons, including pulling up mud. I understand this is a simple method of sizing, I just think it will result in an oversized windlass for someone with a lot of chain.

So I agree with you it is not all that relevant, we just arrived at this conclusion in different ways. Cheers!

Steve

[steve77]

Originally Posted by Steve Bean

I've just done some reading on buoyancy. Everything has some of it, even metals. Iron, for example, when submerged in fresh water, weighs only 85 percent of its dry weight. In salt water, even a little less. So sizing the windlass according to the dry weight of the anchor and chain will result in a safety margin of about 15 percent.

Absolutely correct. Here is my theory - the manufacturers know better than to have their prospective customers try to calculate the volume of the materials in their ground tackle and multiply by the density. Especially when you throw in a multiplier of 3 or 4 at the end of the calculation. There are a lot of people who would simply give up and go on the to next manufacturer who offered a simplified means of selecting their windlass.

Pure conjecture on my part. Cheers!

Steve

[exMaggieDrum]

I have a new Lofrans Tigres in the garage. I will be replacing the Lighthouse 1500 I have installed now. The biggest headache will be the mounting pad and covering the unnecessary holes. This is not a trivial project. It will be easier in a way because the Lighthouse has the motor underdeck even though it is a horizontal capstan and the Lofrans motor will be ondeck.

So the installation effort should be part of your decision making.

1/0 wire was probably OK or just borderline for your previous windlass. Motors don't like a lot of voltage drop. They are happier and live longer without it.

[conachair]

One thing might be worth mentioning if you're getting into it all anyway - adding a cheap garage door remote control piggybacked on the solenoid foot/hand control can be really handy for the sake of an hour or so wiring

[Dockhead]

Originally Posted by double u

+1!
undersized & "sized according to manufacturer's specs" windlasses caused much, much more grief than oversized ones...
if it turns out you oversized: so what, the pain of the expense will be forgotten by then.
if it turns out you undersizes: the pleasure of saving will be forgotten by then too - only the pain in the...will be very acute!

+2!

Just like with anchors - If no one is pointing and laughing at it, it's too small!!

[Wotname]

There have been a couple of posts that have referenced the importance of getting volts to the windlass.

Although not wanting to get to picky about the electrical aspect, please remember that a DC series wound motor does not much care about volts, it wants amps.

AFAIK, most (all?) recreational boat electric windlasses are series wound.

The theoretical aspects of series wound motor tell us that with any voltage source of zero internal resistance will deliver an infinite current into a motor with zero rpm (locked/stalled etc) giving it infinite torque. Whereas an unloaded motor will run at infinite rpm and draw zero current giving it zero torque.

Of course such conditions cannot exist but they help to understand what happens in the real word. The windlass will be trying to draw more and more current the slower it turns and will reach maximum torque when it stalls. The power available at that moment will a product of the volts and current at this point. If the voltage source can deliver more current than the motor is rated at, the windings will burn out (melt/open circuit etc).

What does mean for Steve?

1. If you have a good (great?) power supply then make sure you use the circuit protection recommended by the manufacturer (especially in terms of trip times and percentage overloads). When (not if) the motor stalls, it is essentially a short circuit across the power source. If your source can't deliver enough current, then no harm is done however if it can deliver more current than the motor is rated for, the only thing that will save it is the circuit protection. This is one of the circumstances where the circuit protection is to protect the equipment as well as the wiring.

2. Make sure the wiring has a very low resistance to limit voltage drop at the windlass at the point of stall in order to get maximum torque at this moment.

Of course normal operation does not mean operating the windlass at or near the point of stall

The point being the current available to the motor is the crucial aspect!

[Paul L]

Wotname
The windlass motor should never really fully stall, as the mechanical clutch should not be set tight enough to allow this.

[exMaggieDrum]

Originally Posted by Wotname

T

Although not wanting to get to picky about the electrical aspect, please remember that a DC series wound motor does not much care about volts, it wants amps.

2. Make sure the wiring has a very low resistance to limit voltage drop at the windlass at the point of stall in order to get maximum torque at this moment.

Good explanation Wotname. The real issue is to have a low wiring resistance so the full amps can flow at the needed voltage.

[steve77]

Originally Posted by conachair

One thing might be worth mentioning if you're getting into it all anyway - adding a cheap garage door remote control piggybacked on the solenoid foot/hand control can be really handy for the sake of an hour or so wiring

Not a bad idea, thanks!

Steve

[steve77]

Originally Posted by Wotname

1. If you have a good (great?) power supply then make sure you use the circuit protection recommended by the manufacturer (especially in terms of trip times and percentage overloads). When (not if) the motor stalls, it is essentially a short circuit across the power source. If your source can't deliver enough current, then no harm is done however if it can deliver more current than the motor is rated for, the only thing that will save it is the circuit protection. This is one of the circumstances where the circuit protection is to protect the equipment as well as the wiring.

2. Make sure the wiring has a very low resistance to limit voltage drop at the windlass at the point of stall in order to get maximum torque at this moment.

Okay, I understand about the motor protection, and I'll make sure I address that.

I will also confirm that the wiring meets what is recommended in the manual.

Thanks!

Steve

[steve77]

Thanks, everyone. I will be away from the boat for a week traveling. I may not be checking this forum regularly while I'm gone, but that doesn't mean I've lost interest.

When I get back to the boat, the windlass is my number one project. I spent a sizable chunk of yesterday in the forepeak trying to get the existing windlass out. The four nuts came off easily enough and since the builder used some super adhesive when they mounted the windlass, I used my Fein multitool to cut between the gearbox and the backing plate under the deck. I had the nuts and washers loosely on to keep the whole thing from crashing down if I got it loose.

Well, the windlass is still stuck firmly in place. I have been trying chisels to wedge the unit away from the backing plate but have had no success yet. When I return, perhaps it will be a little more cooperative.

Cheers!

Steve

[exMaggieDrum]

Originally Posted by steve77

Thanks, everyone. I will be away from the boat for a week traveling. I may not be checking this forum regularly while I'm gone, but that doesn't mean I've lost interest.

When I get back to the boat, the windlass is my number one project. I spent a sizable chunk of yesterday in the forepeak trying to get the existing windlass out. The four nuts came off easily enough and since the builder used some super adhesive when they mounted the windlass, I used my Fein multitool to cut between the gearbox and the backing plate under the deck. I had the nuts and washers loosely on to keep the whole thing from crashing down if I got it loose.

Well, the windlass is still stuck firmly in place. I have been trying chisels to wedge the unit away from the backing plate but have had no success yet. When I return, perhaps it will be a little more cooperative.

Cheers!

Steve

Judicious use of a heat gun can often get 5200 and other adhesives to release a lot easier. The windlass would act like a big heat sink though. Some little wedges made out of wood can help by starting at the edges and moving slowly inward. I used butyl rubber tape to remount mine this last time. It seals well and is removable. Good luck.