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Old 10 November 2018, 04:52   #101
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Country: UK - England
Town: South Yorks
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Length: 5m +
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Originally Posted by willk View Post
Well, I'm kinda lost for words. A very long breathless thread with numerous ups and downs. Potentially a fail for the Battery Boat Brigade or a Victory for British Ingenuity (or American Ability) - who can tell?

From my very biased and limited viewpoint, an utter waste of a doner RIB, battery, Torqueedo and whatever money when into it to produce a POS that didn't check a single box other than: 1, Astroturfed a Forum [Check]

Full marks for 'fessing up though. When the Drone Boys were giving you lessons in Capacity and you persevered, it takes big nuts to admit failure.

Awww! Cmon willk, stop being shy, just say what you mean
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
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Old 10 November 2018, 05:36   #102
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Originally Posted by Pikey Dave View Post
Awww! C’mon willk, stop being shy, just say what you mean

I do think that would help!
Mybe being "Borderline" is getting to him

A clever Man learns by his mistakes..
A Wise Man learns by other people's!

The Road to HELL Paved with "Good inventions!"
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Old 10 November 2018, 12:44   #103
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Length: 9m +
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Originally Posted by Pikey Dave View Post
Awww! C’mon willk, stop being shy, just say what you mean
No seriously, he's a field engineer for Torqueedo - I would have expected better than 7Nm at 75% thrust? If some technical gadge from BRP came on here promoting some new Etec gimmick with that level of success he would have been handed his head. I'm grumpy and I'm gonna vent...
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Old 10 November 2018, 13:43   #104
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Originally Posted by willk View Post
....No seriously, he's a field engineer for Torqueedo - I would have expected better than 7Nm at 75% thrust? ....
Me too. I thought he would have got 9 or 10Nm out of it.
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Old 11 November 2018, 12:21   #105
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 10hp Yam / 150hp opt
Join Date: Sep 2003
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Originally Posted by E-RIB View Post
Firstly an apology for not being a little more forth coming with my report how this year and the project has gone.

I do admit to have some teething problems which took some time to resolve, mainly down to software settings, weather windows and not getting full power, as well as boost mode, which gives me an additional 20kw for some seconds to get the rib out of the hole and onto the plane.

I was also lucky to be invited to Cobra ribs for them to weigh the boat. Total weight 1300Kg. This is an issue to me as I had hoped for 1000Kg max. So I went to work putting her on a weight lose plan. helm and rear seat design changed.

When power is minimum and also stored capacity also never enough, as in my case, weight has a big effect and from previous experience 1000kg was a reasonable target, but something I did not hit. It was also clear that this rib ( some 14 years old ) and having been badly maintained was wet and heavy.

But we live a learn.

I also tried the rib with several props and found one size that gave best speed ( 23knots) 13"x 13"
One that gave best acceleration ( for wakeboarding) max speed 20knots 13" x 11"

Range, which is naturally a very big talking point and show stopper, needs some explanation. At WOT my computer calculated 7 nautical miles, which in the grand scheme of things and standard expectations gives us an indication of what 22Kw of stored electricity can do for a 1300kg planing rib with 4 persons onboard so- around 300kg of humans = total 1600kg.
Running at 75% throttle and just on the plane did increase the range but only marginally.

Now, I personally am happy with the speed, all be it not comparable to standard Cobra 6m with 115hp or up some. This rib has a 80hp outboard electric equivalent, so on the verge of being under size. But having said that for what we had intended in doing, having fun, getting out on the water, wake boarding and fishing. This boat and propulsion system works great.

In fact our limitation this summer was not weather, running costs, boat availability, is was the number of opportunities to launch her due to our family time availability.

I calculated it costs 3.70p per full recharge. A result!
This was always one session, maybe a spot of fishing, family wake board session in Christchurch bay or a complete day watching the red arrows/ fishing off Bournemouth.

I recharge her at home, so recovery was always required. Although she was invited to take a berth at Lymington yacht haven and received many interested coments and many test ride were given. There shw always recharged at the berth.... a luxury in my , now well exercised recover and launch lifestyle!

The future plans -
I have now laid her up for a period whilst I do some work to her.
First job - install new battery. The new battery will be reconstructed into a long rectangle housing, that will allow it to be mounted beneath the deck. ( Much better than before)

I was able to sell my old 22kw battery and purchase a 2017 32kw version, all for the same cost! This was a right result and means I practically got 10kw extra capacity for free. Bring on our next opportunity to get her wet again!

As a Mudeford rib user, we are naturally hopeful that one day we can get to Yarmouth, I think with present energy densities of our batteries, we can get there, but not return on one full charge.

I am also looking forward to the future as a BMW i3 42kw battery has now been released and its only a matter of time til I get my hands on one.

I also heard a rumour that BMW are already working on a 60kw and 80kw i3 battery, so it seems i'm in store for many upgrade all meaning my range will increase.

( its worth stating that even as the battery capacity increases, the size of the battery does not. The weight does increase but only fractional)

So all in all a very happy and satisfied 2018 rib user, with great things to come!

See you on the water!
Interesting results.

Looks like there are a couple of issues basically due to the use of an existing boat.

1. The 6m Cobra at 1300kg is heavy. If you were to build from scratch you would be able to build much lighter. 80hp pushing 1300kg is always going to be marginal.

2. The Cobra hull form is not optimal for the speed you are running at. It has a deep V centre section with flatter sections outboard. This works well at high speed - effectively just running on the centre section. Probably optimised for 35-40kts. If you were starting from scratch you could optimise the hullform for the expected speeds (20-25kts?). A Shallower V could be used perhaps with more deadrise forward for seakeeping. A shallower deadrise hull would be more efficient / faster / need less power / greater range.

100hp on my Ribtec 585 is plenty.

I reckon if you were to build light with a hull optimised for 20-25 knots you could almost double the efficiency.

Avon now have a full electric tender - so to the naysayers you're not too far off!

With the battery sizes when you say 32kW do you mean 32kWhr?
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Old 20 November 2018, 14:53   #106
Join Date: Jun 2010
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Seen this 450hp monster, they have a 100 and 200hp coming too.

No info on battery specs yet but probably safe to say will be few big Duracell required.
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Old 20 December 2018, 12:40   #107
Country: UK - Scotland
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Originally Posted by Xk59D View Post
Seen this 450hp monster, they have a 100 and 200hp coming too.

No info on battery specs yet but probably safe to say will be few big Duracell required.
It's the V12 diesel genny under the console that offsets the clean engine!

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rib, torqeedo

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