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Old 12-11-2021, 12:50 PM   #321
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It wouldn't work on most motor yachts, but please remember our extreme focus on designing an underwater-ship that is very efficient.

My own opinion here, and I mean this with all respect and deference to your own priorities and choices, but I think this is very much the wrong focus for 99% of boaters. I think it only makes sense if:



1) You are doing it primarily as a science experiment to explore efficiencies are various designs, or


2) You intend to be at sea on passage nearly all of the time.


Only you can speak to either of these goals, but I do know that the most intrepid cruisers I know, including those who have ventured around the world, spend well less than 5% of their time on passages.


As a result, power cruising boats have evolved to where they are today. In Bebe's pioneering days when he was trying to prove the viability of long distance power cruising, his boats looked like sail boats with the masts removed and larger engines and fuel tanks installed. With no need to watch sails all the time from an open, aft cockpit, those wet, cold, uncomfortable helm stations moved inside. But now the helm and house were sharing the same space creating a conflict over lighting during night operations. So the helm moved to a pilot house. And all that extra fuel stored down low, along with the engine and other machinery, had the fortuitous effect of moving the salon up to or above the water line, and everyone realized how nice it was to no longer be living in a cave. Then with the helm moved out of the cockpit, people realized that was a really nice space for fishing, or just hanging out to enjoy the outside when the weather is nice. It also makes for a convenient boarding area. Then people realized that when the weather is nice, it's great to operate from outside, so the fly bridge was born. And it sure is a nice view from up there, plus a great place to just hang out and enjoy the view. And along the way people realized that there isn't really that much difference in operating cost if you have a wider beam, but you sure can have a lot more living space and a more comfortable boat, so boats got wider.


If you look around, I think there are a lot of reasons why power cruising boats are set up the way they are, and why they out-number FPB-style boats probably a thousand to one.



And on folding props, don't be tempted. The noise and vibration from a folding prop is massive compared to a properly sized fixed pitch prop. They are a necessary compromise on a sail boat, but not on a power boat. Smooth and quiet is preferable, in my opinion.
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Old 12-11-2021, 01:09 PM   #322
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Thanks for sharing, TT!

Yes, the boat is designed to be sailing (or motoring) most of the time. Yes, the standard cruiser/trawler sales heavily outweigh FPB-like designs. Yes, I think Bebe was spot on with his design priorities.

I feel - personally, so for me - that a way back to his original ideas would be a step forward. Especially since modern technology makes it much more viable. My focus - like his was - is on crossing oceans. And on making it a safe and totally enjoyable affair.

Regards, Edwin.
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Old 12-11-2021, 02:12 PM   #323
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... and wider ships do come at a hefty efficiency cost.

Regards, Edwin.
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Old 12-11-2021, 06:43 PM   #324
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Our first calculations show that in moderate winds it'll take the ship to 6 knots.
I’m not a sailor and my only technical degree is in hillbilly engineering, but I’ll still say getting that boat to run 6kts with a kite alone will be tough to achieve.
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Old 12-12-2021, 02:03 AM   #325
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kite calculations

Here are som initial calculations, gentlemen. A work in progress, so still to be fine-tuned. But the grit of it goes as follows:

At a wind difference between sailboat and wind of 5 m/s (5 meters per second or 17 feet per second), a square meter of sail produces about 1 hp. The 1 hp per m2 includes the inefficiency of the ship being pushed over. Keeping a sailboat at angle costs energy.

Kites deliver a higher output per m2 than sails. Research from Delft University shows at least an improvement to 1 kW per m2 or 1.36 hp per m2. The efficiency gain comes from a kite-driven device usually not needing a long arm (aka mast), and the kite propulsion system thus creating less leverage (hope that's the right word), resulting in the generation of more net energy.

In other words: less power is lost to keeping the vessel at an angle, resulting in better efficiency numbers. Hence the kite outperforming the traditional sail by at least 36%.

Now that we know that a kite produces at least 1.36 hp per m2, let's investigate how much power is needed to propel our ship at 6 knots. The power needed is 13 hp (see picture of the relevant resistance-to-power chart for our ship's design underneath).

Knowing the power delivery of a kite per m2, the power that's needed to propel our ship at 6 knots, we can now make a calculation of how big the kite needs to be. 13 hp divided by 1.36 equals ... about 9 m2.

Regards, Edwin.
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Old 12-15-2021, 10:13 AM   #326
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On ocean passage have used
Double head sails no main
Asymmetric and symmetric spinnakers
Bought and used a parasailor on last boat
Codes 0 and 1

The universal difficulty is all winds vary 10-20 degrees in direction and all winds vary in intensity. Degree of these variations vary in degree but are always present to some degree. So apparent wind varies in direction and intensity. But there’s also always a fall in the speed of the apparent wind the faster you go.. For efficiency you need to trim. This remains true for kites. For a fully manned race boat that’s a non issue. For a cruising boat that’s a PIA. Many cruisers get around this by not going DDW. There’s is a fall in efficiency but by not going DDW the sail plan is more tolerant of minor fluctuations in direction and apparent wind speed. This is routinely seen as a improved VMG as on passage as long boards are possible. Gyping at change of watch isn’t onerous. Kites are less tolerant of going to a far reach and do require more attention if you do.
So think kites are a viable get home fallback but also think it will end up something you have but don’t use. We spent a bunch of boat bucks on our Parasailor. Only used it when there were at least 3 experienced sailors on board. Ended up using double headsails no main 95% of the time when going down wind. Especially on passage as with reliable roller furling pull two strings and no rags up. That could be done by one crew so thought that the safest set up for passage.

Forgetting headers and lifts going down wind there’s holes. That sail hits a lull or gets back winded from inattention it will collapse. Maybe you save it before it gets wet. Maybe not. Then given boat speed will only slow gradually you have sail and string under the boat. Not fun. Sure hope for the best but plan for the worst. Personally wouldn’t fly a kite on passage in powercraft except in anger(get home) or extremely limited settings.
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Old 12-16-2021, 01:46 AM   #327
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We see the kite addition as something that can be used on longer stretches, taking advantage of trade winds, for instance.

Currently, we are talking to several ship yards to see which one is best suited to help us build the first LM65h! Very exciting stuff!

Regards, Edwin & Veronika.
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Old 12-16-2021, 05:36 AM   #328
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Edwin
A few years ago we met up with an aluminum 65' sailing vessel called Thor. Thor is an amazing boat and owned by a serious globe girdling couple. When looking at your post#1 it checks a lot of the boxes. Google sailthor.com for details.
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Old 12-16-2021, 06:35 AM   #329
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Thanks! We'll look her up!

Regards, Edwin & Veronika.
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Old 12-16-2021, 08:54 AM   #330
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Updated picture LM65h

Here's an updated picture. We added windows to the back of the main room. This makes it possible to sit on the bench on the outside aft deck and still maintain vision on what happens in front of the boat.

The dingy is also added. As well as three mobile davids systems. That's just to see how positioning would work. In reality, there'll be only one davids system that can be applied on multiple locations.

Regards, Edwin & Veronika.
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Old 12-16-2021, 10:09 AM   #331
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Always wondered about dinghy storage on passage. With dinghy upright it wouldn’t quickly clear green water if subjected to a boarding sea or a pooping. Water is 65lbs/cubit ft.. is this a concern? Does that stil allow use of a drogue in case of a complete mechanical failure?
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Old 12-16-2021, 01:08 PM   #332
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From the render it looks like Hammerhead's aft platform has about 2 or 2.5 ft of freeboard. It would have to be large seas to poop the dinghy, which would obviously have a tight cover on it.

I remember Robert Beebe's comments about storing the dinghy upright, and how it was a fantastic place to store hundreds of pounds of stores, bananas, etc. during a long voyage.

Edwin, have you thought about a small step (say 2' deep) at the aft end for use as a convenient swim platform that would be about 8" from the water - or will you be relying on a removable swim ladder?
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Old 12-17-2021, 01:21 AM   #333
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Mako, there will be a swim ladder, I think. Will discuss further with NA, but think it is required for CE-A certification by definition.

The dingy can both be covered tightly, yet also has a drain. it is an aluminium structure with ribs around it.

Bebe's idea of using the dingy for additional storage is a nice one, indeed. Not completely sure we need it, since the yacht will be 65 feet and will be couple-operated most of the time.

Regards, Edwin & Veronika.
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Old 12-23-2021, 04:45 AM   #334
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Just sharing some of the design updates on phase 2 of the development of the LM65h ...

Since we already have a mast for the kite, I decided to extend that and also house the radar, etc. there. The mast will fold down, when needed.

Advantages over the original position are a lower overall profile with the mast folded down, allowing for French canal cruising as a means to travers Europe via inland water ways. And less hard shadow for the solar panels that will be situated on top of the roof of the main cabin.

Here is a first picture. It teaches us that we still need to raise the mast by about 3 feet, in order to get a clear radar resolution looking back.

Regards, Edwin.
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Old 12-23-2021, 09:37 AM   #335
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Speaking of radar, have you worked out what other electronic need to be located outside, and where they might go? Competing location requirements make it a difficult puzzle to solve, with no real “solution”, just the most optimal compromise.

At a minimum I expect you will need locations for:

3 VHF antennas, two for radios and 1 for AIS

- A weather instrument

- A sat compass

- A gps mushroom for the AIS

Then given your cruising goals, you may want to double up in things for redundancy. That would lead to:

- Second Radar
- back up mushroom gps

Also maybe add a FLIR camera.

Then there is communication. At a minimum and external Iridium antenna. Also external cellular and WiFi antennas. And maybe a sat dome?

I fitting the final puzzle pieces on my boat so this is front on my mind.
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Old 12-23-2021, 09:58 AM   #336
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Designing & Building Hammerhead

And along those lines, I would suggest that the front mast mounted radar be a 4G. Although their performance is not comparable overall, having one could provide the excellent close-in detail needed for navigating around obstacles within 100ft or so. I found lots of fishing hazards myself in SE Asia and the Persian Gulf - wow what a nightmare!

Then use the large radar arch at the stern for a real man’s open radar and all the other stuff @TT mentions.

Also since the 4G is for forward-looking primarily, your mast does not need to extend too high.
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Old 12-23-2021, 10:34 AM   #337
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Thank you for chiming in, gentlemen.

Here's what I am looking at now:
- Raymarine Quantum 2 doppler radar (great detailing, low power consumption, 20 Nm reach);
- Double VHF;
- Double GPS mushrooms;
- AIS;
- Weather instrument.

I am expecting we'll add a FLIR, but that'll probably sit on the forward rim of the roof on the main room.

For satcom and internet, I am expecting StarLink to be a viable option by the time the ship launches.

Anything I missed?

Regards, Edwin.
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Old 12-24-2021, 05:13 AM   #338
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I think the Raymarine M300c would be a great FLIR option. What say you?

https://sensormaritime.com/wp-conten...tasheet-EN.pdf

The M400 is ... offering a bit more, but very, very cost prohibitive. 70-80k vs 7-8k.

Will probably be installed in the mast, just under the radar ...

Regards, Edwin.
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Old 12-24-2021, 05:21 AM   #339
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My opinion? Time to stop planning and designing and start building
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Old 12-24-2021, 05:48 AM   #340
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Thanks Dan! That's where my heart is as well.

Regards, Edwin.
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