50' Cat with 12f draft???

[valhalla360]

Originally Posted by David Ess

Valhhala, I think youre right about the motors/generators, and various options. Ive read a fair bit about these various european builders going hybrid, and im pretty sure theyre all claiming about 25% or more, overall. In fact, even re cars, I have a Hyundai Ionique and get way better milage on long trips too, not just in cities. I guess this boat it holds about 2600US gallons of fuel, and it seems impossible to calculate its milage, I like speeds of 5kts.
Also, I mentioned that there is capacity for about 10kw of solar panels above the huge work deck. All that charging the massive battery bank would help with the rangeThats what id do instead of toys. Hopefully they will send me the tech specs, etc. I cant find any price anywhere, but its likely over $2milion. By comparison, a 'fancy' hybrid catamaran, the Silent 55, is about 2.5million.
I think this would make a great long disyance boat.

Big improvements with hybrid are almost exclusively with stop and go operation. Otherwise, it's more efficient to spec an appropriately sized diesel and connect it directly to the prop. Hybrids rely on capturing power output that would otherwise got to waste (or running the motor at an inefficient speed). If you are running at a steady cruising speed most of the time, they can match the most efficient motor output to power demand pretty closely, so there is little or nothing to gain from going hybrid. In fact converting power to electric and then back to kinetic energy will waste some power.

Again, on a service boat never intended to run more than short distances before stopping and maneuvering, hybrid can make a lot of sense. For straight line several hours at cruise speed getting from A to B, I can't see them getting 25-30% improvements.

As far as 10kw of solar...at peak output, that's around 13.5hp or if you are looking at total energy generation per day you can figure around 40kwh. On a boat that requires a 500hp engine, that's maybe enough to maneuver around the marina but not enough to get any significant propulsion. What it could do is take the place of the generator for house loads. Depending on the overall size of the interior and how well insulated, it might even cover air/con.

[David Ess]

Valhhala, fair enough if you disagree with all those clever Scandinavian and German engineers that prefer serial hybrid, instead of parallel hybrid. Certainly I cant argue their case. And for sure , we see many parallel hybrids too, and serial/parrallel ones, likecmy Ionique car. too. On your one point though about requiring a 500 hp, it s not a case of this boat ...requiring that, but is one of several options. Somebody mentioned 100hp ones I guess. And Ive seen such ads in the various lit by builders. One of the factors there is the speed the customer wants to achieve. Some want 20kts...others 10, and me 5kts. It makes a big difference you have to know.

[dougweibel]

Your pictures have not swayed me. The berth with armchair picture reminds me very much of my accommodations in the arctic - no windows. Galley - no windows. Living room - small windows you can't see out while seated. Not what I would want for my home.

From the beginning I have not tried to dissuade you, but have only pointed out such a boat will not appeal to most as a cruising boat. If it is what you want then that is great. My preferences should not impede or insult you. There is no reason to take offense at others saying what they see as weaknesses in a boat that appeals to you, or even a boat you own. Boats are compromises. There are plenty of things others don't like about my boat. There are things I myself don't like about my boat, but on the whole I like it a lot.

If I see you in some anchorage some day in a NabCat I'd be happy to have sundowners. I'd probably tell you you have a cool boat. There are lots of cool boats that I'm glad other people own.

[David Ess]

Originally Posted by dougweibel

Your pictures have not swayed me. The berth with armchair picture reminds me very much of my accommodations in the arctic - no windows. Galley - no windows. Living room - small windows you can't see out while seated. Not what I would want for my home.

From the beginning I have not tried to dissuade you, but have only pointed out such a boat will not appeal to most as a cruising boat. If it is what you want then that is great. My preferences should not impede or insult you. There is no reason to take offense at others saying what they see as weaknesses in a boat that appeals to you, or even a boat you own. Boats are compromises. There are plenty of things others don't like about my boat. There are things I myself don't like about my boat, but on the whole I like it a lot.

If I see you in some anchorage some day in a NabCat I'd be happy to have sundowners. I'd probably tell you you have a cool boat. There are lots of cool boats that I'm glad other people own.

Fair enough, as with so many things in the boating world its a matter of taste and compromise. In fact the nabcat is TOO fancy in some ways, like with those wood floors we see in the pics. Im fine with bare alu deck plate, with persian throw carpets in a few places. Re the galley, for me just a place to cook food, and eat on the pilot house tables where you have a view. Living room? Thats for nitetime when you can see outside anyway. Small windows=stronger. Same with cabins, for sleep, not views. Different taste.

[valhalla360]

Originally Posted by David Ess

Valhhala, fair enough if you disagree with all those clever Scandinavian and German engineers that prefer serial hybrid, instead of parallel hybrid. Certainly I cant argue their case. And for sure , we see many parallel hybrids too, and serial/parrallel ones, likecmy Ionique car. too. On your one point though about requiring a 500 hp, it s not a case of this boat ...requiring that, but is one of several options. Somebody mentioned 100hp ones I guess. And Ive seen such ads in the various lit by builders. One of the factors there is the speed the customer wants to achieve. Some want 20kts...others 10, and me 5kts. It makes a big difference you have to know.

I'm not disagreeing with them. I'm saying their numbers are based on a use case that is not consistent with typical pleasure cruisers use case.

You also misinterpret the comment about the 500hp motor. You will almost never see the motor putting out the full rated 500hp. They put in larger motors so it can provide higher output at low RPM for maneuvering and accelerating (consistent with a service boat that does a lot of starting and stopping). Most likely something on the order of 40-60% of the rating will be typical output at cruising speeds...so let's call it 250hp output in a typical use case. Drop it to 5kt and maybe 100hp actual output is viable.

10kw of panels generating 40kwh (55hp-h) is going to be good for less than 1hr cruise time or about 5nm...Yes, technically possible but highly impractical and costly.

[David Ess]

Originally Posted by valhalla360

I'm not disagreeing with them. I'm saying their numbers are based on a use case that is not consistent with typical pleasure cruisers use case.

You also misinterpret the comment about the 500hp motor. You will almost never see the motor putting out the full rated 500hp. They put in larger motors so it can provide higher output at low RPM for maneuvering and accelerating (consistent with a service boat that does a lot of starting and stopping). Most likely something on the order of 40-60% of the rating will be typical output at cruising speeds...so let's call it 250hp output in a typical use case. Drop it to 5kt and maybe 100hp actual output is viable.

10kw of panels generating 40kwh (55hp-h) is going to be good for less than 1hr cruise time or about 5nm...Yes, technically possible but highly impractical and costly.

Qurite right on your comments about a ,500hp motor.....IF a normal boat. But this is not, apparently its a serial hybrid one. If true, that means the motor operates at its sweet spot to charge the 462 kWh hr of batteries. So on your point about manouvering, in such cases it only needs battery power, to eliminate pollution and noise while docking, etc. and That much capacity is plenty to do that in any harbour/bay, right? And with electric motors you can go as slow as ONE rpm, one side forward, the other hull in reverse While in port, or out, all those solar panels continue to recharge. They list an electric engine of 350kw...presumably they mean one of those on each hull. Some catamarans have only one genset, some two...its not clear in this case.
Another big issue for us both is that we dont know the discplacement...not even the draft of this boat. If you also find it interesting, maybe you would also try to click on their ..send me details.....place. Ive tried twice, and havnt heard from them. Perhaps they only respond to big companies.

[valhalla360]

Originally Posted by David Ess

So on your point about manouvering, in such cases it only needs battery power, to eliminate pollution and noise while docking, etc. and That much capacity is plenty to do that in any harbour/bay, right? And with electric motors you can go as slow as ONE rpm, one side forward, the other hull in reverse While in port, or out, all those solar panels continue to recharge. They list an electric engine of 350kw...presumably they mean one of those on each hull. Some catamarans have only one genset, some two...its not clear in this case.
Another big issue for us both is that we dont know the discplacement...not even the draft of this boat. If you also find it interesting, maybe you would also try to click on their ..send me details.....place. Ive tried twice, and havnt heard from them. Perhaps they only respond to big companies.

On a sail boat using batteries for port maneuvering is viable if you are willing to rely on the vagaries of the wind...this is a power boat, so that's doesn't control the design. You need power on demand any time you are under way.

1 RPM is meaningless. No one is ever going to purposely operate at 1 RPM. Fun theoretical point but it serves no practical purpose.

At 250hp output, the 500hp engine is going to be pretty close to peak efficiency, so a hybrid isn't going to add much having a generator putting out 250hp converting it to electric, storing it in the battery, then converting back to electric before converting it to kinetic energy. There is no delta in energy production vs demand to gain back the losses.

If you do plan to cruise at 5kt with maybe a 7-10kt top speed, you might be able to drop the engine size to something on the order of 100-150hp/engine. Pending response from the company, that would be the way I would lean for a cruising boat.

As mentioned, one of the pictures showed the plimsoll lines with 1.8m at the waterline, so there is a pretty good idea of the draft. I suspect they don't list draft as it's a commercial boat and the draft can change significantly depending on the cargo. Cruising boats list draft based on assumed loading for typical cruising.

With an 80ton cargo capacity and 4m wide hulls...it's likely an absolute beast compared to a similar size fiberglass cruising catamaran. Also, I'm betting the hulls aren't designed for maximum efficiency but load carrying capability

Again, pending pricing and some other details, I think the boat could make an interesting cruising boat...but the hybrid aspect is likely not a key selling point in terms of fuel savings.

[David Ess]

Originally Posted by valhalla360

On a sail boat using batteries for port maneuvering is viable if you are willing to rely on the vagaries of the wind...this is a power boat, so that's doesn't control the design. You need power on demand any time you are under way.

1 RPM is meaningless. No one is ever going to purposely operate at 1 RPM. Fun theoretical point but it serves no practical purpose.

At 250hp output, the 500hp engine is going to be pretty close to peak efficiency, so a hybrid isn't going to add much having a generator putting out 250hp converting it to electric, storing it in the battery, then converting back to electric before converting it to kinetic energy. There is no delta in energy production vs demand to gain back the losses.

If you do plan to cruise at 5kt with maybe a 7-10kt top speed, you might be able to drop the engine size to something on the order of 100-150hp/engine. Pending response from the company, that would be the way I would lean for a cruising boat.

As mentioned, one of the pictures showed the plimsoll lines with 1.8m at the waterline, so there is a pretty good idea of the draft. I suspect they don't list draft as it's a commercial boat and the draft can change significantly depending on the cargo. Cruising boats list draft based on assumed loading for typical cruising.

With an 80ton cargo capacity and 4m wide hulls...it's likely an absolute beast compared to a similar size fiberglass cruising catamaran. Also, I'm betting the hulls aren't designed for maximum efficiency but load carrying capability

Again, pending pricing and some other details, I think the boat could make an interesting cruising boat...but the hybrid aspect is likely not a key selling point in terms of fuel savings.

The 1 rpm of an electric boat means something, not that anybody would do it, bot you might do 100 if forward on one hull, and 100 reverse on the other for accurate, easy, silent , non polluting docking. And yes, if no 80 tons cargo, you can have small motors for cruising, charging batteries. I also figure draft is about 2m or so.

I think id like a robust commercial boat like this one. Only 50', but lots of room for various possibilities. i wouldnt hesitate to take my kids thru the NW passage in it.
Another hybrid this company has is a 21m fishing boat too, monohull, which also looks real interesting, you can see on their site.