First point:
Thank you for generously sharing your thoughts and experiences Rick!

| Point by point as below:
|
| 3. The best place for a propeller when sailing is out of the water; easily accomplished with outboards or deployable thrusters.

Or tilt down tender?

| 4. The regeneration mode with modern electronic controllers is very effective over a wide range of speed. The mode works fine with a boat that has a narrow operating speed like moderate displacement sailing boat. A HP will typically motor at 6 knots and sail up to 20kts. When sailing at 6knots you do not want to be slowing down to 3knots or even lower to charge batteries.

Why not? Given the expected charging is not working as desired, and you are onto the backup systems, one might just choose to sail at 6kts to charge the batteries. Perhaps, with the 'considerable drag', more than 6kt might be impossible?

Given you know you need some portion of a full bank to motor as required in a few days, a sailor would think ahead and make said choice, right?

| If you forget to lift the motor once the wind builds it will be spinning well above its design speed and at risk of throwing windings. Cage type induction motors are usually most tolerant of overspeed but they are the most expensive option.

Perhaps. But there is that considerable drag.

If one is building a custom battery electric propulsion system with solar, wind, and prop dragging charging, perhaps, one might be able to add a reminder to not over speed the prop. Perhaps even a lifting mechanism or a fuse?

Or, perhaps, the tender might be designed to go 20kts? So it really wouldn't be over speeding it? Or is that silly?

| 5 &6. Every detail in the building and operation of a HP is planned to perfection and nothing ever goes wrong- yah right!

As the kids say, LOL. While the planning might be there, no plan survives contact with the enemy.

| There is simply not enough room for solar panels on any HP to enable energy collection for reliable motoring in a cruising situation; meaning having enough stored energy to get through a difficult situation or period. A LiFePO4 battery requires about 15kg of battery for each kWh you can get from an electric motor.

https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
Suggests 5kg per Kw.

Who is wrong here Rick?

| A diesel requires 0.25kg of diesel for each kWh it will deliver at the shaft. Carrying 100kg of diesel stores the equivalent of 6 tonnes of battery storage. A realistic battery weight of 100kg will give about 2 hours of conservative motoring. That is often not enough to get out of trouble.

Is it naive to suggest one should not expect a motor to save a sail boat?

| An example, I run some of my home load off grid and the solar/battery system is designed to supply power through winter on the basis of getting no less than 2 hours of full sunshine equivalent over 48 hours. The battery went flat in late June this year and the same time of the year in 2014. You may think this is just a function of living at 37S latitude but I have looked at the solar insolation over the whole of the east coast of Australia and there are periods of 3 to 4 days without sunshine; usually associated with a tropical depression developing into a rain depression. Even if you litter the entire deck and cabin top of a HP with solar panels you will have the fridge off, autopilot off, GPS off and any other non essential load so you will be able to just power nav lights or anchor light at night. Running a diesel for 10 minutes will provide what you get from solar panels over a whole day in overcast conditions.

Sure. That's why I am asking about backups. Certainly the wind turbines and prop dragging could help on the low solar weathery days?

If you are single sourced, expect that you will not have enough power from time to time.

| 7. You can live with solar panels and batteries alone for day sailing - if batteries are low you stay at home or use shore power to charge them.

I am not sure how your Number system corresponds to the points I am making. But I am guessing this is the part where I asked

|> Or are you saying there is no other viable alternative to hydrocarbons?

|> If, in your considerable opinion, spinning the drive motor is a crappy way to make power, that cannot be made worthy, then please say so. If it is only very difficult and tedious, but doable, then that's a different thing.

And I find it a non reply. You do list ways of powering, but not if prop driving a generator is viable. Or non viable.

It is, however an expansive response. So I will engage.

| No matter how a battery is charged it will have limited range because weight comes with capacity and that is not consistent with the HP concept.

Weight is always capacity. From food to toilets, laundry to to liquids, weight is always required, and it's limit is the limit to range.

Yes, batteries are heavy. As are diesel gensets. The difference being batteries are getting cheaper and lighter every year.

| If you are relying on wind to charge the battery you may as well be making the best of sailing because you will be losing 3 to 5kts to charge the battery over a few hours and the lost ground will not be made up motoring when the wind drops.

Unless you are willing to trade knots for power in your batteries. You may not see that as viable, but how can you say no one will? If you know you need to motor into a location in a few days, and need your battery pack at some level of fullness, it seems a reasonable trade off. Not everyone is gonna sail their boat at top speed always.

| 8. The original drive on the 18m proa was ...
| Direct coupling a diesel to a prop brings up a whole lot of issues.

What would be wrong with one directional, tenderish drive as suggested by the more recent if Robs designs?

It may not be practical for the 18m proa. But is it practical for HP's?

| If the props are permanently in the water they are offering considerable drag.

Why leave the props in the water permanently?

| Access in the narrow hulls is very tight for mounting and maintaining motors.

Why put them in the hulls?

| Two motors are required rather than one. Even if the props can be feathered they have to be able to stay feathered in both directions at 15kts or more otherwise they present substantial drag.

Why would you not lift them?

| The water intakes need to work reliably in both directions and be such that they do not force water into the motors when at speed.
| An outboard on each hull for a smaller HP is not a bad option but they will need to cope with a lot of water over them when motoring in windy conditions. A bi-direction boat is not the ideal location for an outboard primarily designed to go one way while mounted on a broad transom that rarely gets submerged. Also storing gasoline has higher fire risk than storing diesel.

Oh, I see, you are discussing the 18m proa, not a HP.

It seems on a HP, with a tilted tender, much of this applies to a more or less degree, right? Some of it not at all?

Should one assume a HP NEEDS to motor in either direction? Is there a reason I cannot see to assume bidirectional motoring?