Mantus rode

[Delfin]

Originally Posted by skipmac

Ooo. An underwater drone. What a cool toy to have. Assume it has a wired connection to the controller as I don't think radio waves penetrate underwater very well.

Check it out....

https://www.youtube.com/watch?v=43Vkc3ae95I

This is what my dock buddy purchased, but I think he said they now cost close to $2k.

[Dockhead]

Originally Posted by Delfin

Yes, it comes with a 25 meter hard wire and an optional 100 meter control wire. My Geekometer pegged when I saw it.

*like*






https://www.amazon.co.uk/Thor-Roboti...gateway&sr=8-9

[skipmac]

Originally Posted by Delfin

Yes, it comes with a 25 meter hard wire and an optional 100 meter control wire. My Geekometer pegged when I saw it.

I probably shouldn't even ask this, but where does one find one of these and how much does it cost?

[Dockhead]

Think of the tools you could pick up off the seabed in marinas, with that ThorRobotics one with the arm.


Pay for itself in no time!

[Delfin]

Originally Posted by Dockhead

Anchor performance apparently doesn't scale once you get over 100 pounds. Dashew had great luck with his 176 pound Bruce anchors, and most Sundeers apparently still have the ones they were delivered with.


You should be getting over 30 tonnes of maximum holding power with that anchor -- what kind of rode do you use with it? That would be beyond the breaking strength of most human scale chain.


12 tonnes on 3:1 scope; probably hardly any reason to use more than that, with such an anchor. A great example of what we have been talking about.

1/2" G4, snubbed with 30' of 3/4" Octoplait with Amsteel on the boat end to resist chafe. Each component is rated as stronger than the chain, so around 4.5 tonnes minimum working load.

I sleep well at night once anchored, even if Rod believes I am endangering the lives of everyone within 1000' of my vessel with my cavalier disregard for safety and physics.

[Delfin]

Originally Posted by skipmac

I probably shouldn't even ask this, but where does one find one of these and how much does it cost?

Here you go: https://store.openrov.com/

2 boat bucks, more or less.

[Dockhead]

Originally Posted by Delfin

1/2" G4, snubbed with 30' of 3/4" Octoplait with Amsteel on the boat end to resist chafe. Each component is rated as stronger than the chain, so around 4.5 tonnes minimum working load.

I sleep well at night once anchored, even if Rod believes I am endangering the lives of everyone within 1000' of my vessel with my cavalier disregard for safety and physics.

Same chain as mine, so breaking strength of about 8-9 tonnes. So with that at 3:1 in good holding you would break the chain before you pulled it out of the seabed. Nice.


I want an anchor like that. And the next boat will have one -- the big Spade, I guess.

[transmitterdan]

Wearing that VR headset when standing on the bow will get you a geek award for sure. Just be careful you don’t trip over a lifeline and become a MOB with a bulky headset over your eyes.

[Delfin]

Originally Posted by transmitterdan

Wearing that VR headset when standing on the bow will get you a geek award for sure. Just be careful you don’t trip over a lifeline and become a MOB with a bulky headset over your eyes.

Yep, that would me. But I'll probably be dead long before that due to short scope anchoring.

[Delfin]

Originally Posted by Dockhead

Same chain as mine, so breaking strength of about 8-9 tonnes. So with that at 3:1 in good holding you would break the chain before you pulled it out of the seabed. Nice.


I want an anchor like that. And the next boat will have one -- the big Spade, I guess.

Yes, I feel very manly when I pull into an anchorage. I've always thought Dashew had it right on what is the right size of anchor for your boat. You're getting close when people look at and remark that it is way too big.

[skipmac]

Originally Posted by Dockhead

Think of the tools you could pick up off the seabed in marinas, with that ThorRobotics one with the arm.


Pay for itself in no time!

Oh yea. I can go find that 6mm Allen wrench I dropped (that probably sank in 3' of mud). That would justify one of these right off the bat.

[ramblinrod]

Originally Posted by skipmac

Oh yea. I can go find that 6mm Allen wrench I dropped (that probably sank in 3' of mud). That would justify one of these right off the bat.

[Dockhead]

Originally Posted by TommmD

So, I have a 35 lb Mantus on a rode 5/8" x 200' 8-strand spliced to 3/8"x15' d4 chain. This was built for my present 36 Hunter, 12,000 lbs + crew + gear.
Trading up to a 40' , 18,000 lbs + crew + gear.

This anchor felt oversized for the 36, so I'd like to think its more appropriate for the new boat. Plan on replacing the present 15'of chain with a longer length, somewhere between 50 & 100', but this is guesswork.

I'm in New England, if I anchor in 40' thats a lot, and 200 nylon+100 chain is over 7:1. That sounds like quite a bit. 100' of chain is 140 lbs + 35 lbs, all on the nose. 50 ft of chain cuts thats down to 105 lbs, but I'm thinking I should split the difference.

Is my thought process prioritizing the wrong thing here? How out of whack is all this? I just spoke to a friend with a 42' 24,000 lb boat (+ +) & he's carrying 300' of chain!

Thx for the thoughts,

Back to the OP. I hope we didn't scare him away with our "lively" discussion!


Only you can answer this question for sure -- everyone uses his boat differently, and anchors in different places.


18,000 pounds or only 8-odd metric tonnes is light for 40 footer, so you will want to be careful about too much weight in the bow.


So here in my opinion is a good case for heavier anchor/lighter chain as recommended by many experts. What kind of windlass does the boat have?


In a place like New England with a lot of rocky bottoms (if you go up to Maine for example), I would not personally skimp on the chain and not use less than what you have. You can reduce the weight of it by going to one size smaller G70 high strength chain.


Like others, I think a 35 pound anchor is light for a boat your size. The Rocna chart calls for something between 20 and 25kg, and the Mantus chart even says you need 30kg for a "storm" anchor (that is, an everyday anchor you can really count on) -- I would definitely go for at least 25kg unless you are really just weekend sailing and don't have any significant risk of having to anchor in any bad weather, short scope, etc.


I would suggest using the biggest anchor you could be comfortable with, at least 100 feet of one size smaller high tension chain, and as much rope as you feel like carrying.


There is a really good thread on here where sailors compare actual experience on different amounts and types of rode while crossing the Pacific, which is quite relevant to your situation I think: Minimum chain length for the pacific - Page 4 - Cruisers & Sailing Forums


You'll see there a lot of ways to skin this particular cat.

[weavis]

Thread opened.

[weavis]

Ive been waiting for the thread to debate which is the best make of anchor!

The truth is, I think in reality, and for a variety of reasons, we become attached (sic) to our equipment. Large expense items for poor Brit boys was a case of making a choice and being stuck with it.... (age 14-20)

England is a Tidal country, and us going out fishing... we would drift about a mile or a mile and a half offshore, just beyond the tide range, and sling the anchor when we hit a fish shoal. Our technique was to let it bottom, and then if the tide was flowing or ebbing, let the water settle it firmly...

None of us gave much thought to anchoring, you see, it just worked...

Having gone through a series of ever larger vessels both motor and sail as the years passed, and with a better income, the anchors got larger and heaving them over became mechanised... they still held in the main.

Ive learned a lot from this thread.