Anchor Rode Weight Bias

[Nomad Willy]

Ranger,
"Quote:
Originally Posted by manyboats View Post
So one can have reasons to use all chain .. but none of them are objective.

I over stated or tried to simplify too much. There are objective reasons to use all chain like you don't trust the splice .. or any other good reason. But gaining anchor performance is not one of them. If you use the same weight of rode in a combo configuration you will enjoy higher performance. So chain above the midway point between the anchor and bow is excess baggage if compared to a combo rode of the same weight. The weight of the upper all chain rode is just better spent on the lower half of the rode.

If you anchor in Alaska in 50 to 100' of water the load on the windlass will be high. But if there's not much wind or current one can give the winch a cool down break mid way up. Having 50' of chain would be an advantage.

FF
Most would usually have more than one aboard.

waddenkruiser,
Few agree w me here but I think saving weight on any pleasure boat is worth doing .. maybe not w the money factor included but if I had an all chain rode and a fairy godmother I' ask her to make my all chain rode into a combo rode of the same weight w chain on the first 25% of the rode. But if I already had a 200' rode of 1/4" chain i'd just leep it around here but if I was back in Alaska I'd want at least another 100' of line included. But if I was building a new boat I'd huck the 1/4" chain and use about 50' of 3/8ths and 200 to 350' of line depending on location. But not all chain.
I sure like your "ultimate catenary - stiff rode" range description of anchor performance .. Or should I say rode performance?

 

[Art]

I strongly recommend to read Eyschulman post # 16.

Therein truth of physics is stated best for the most well rounded effect that can clearly affect the multi needs regarding anchoring small to mid-sized boats.

 

[Nomad Willy]

I did Art,
Yes the longer the rode the better. For scope in deep water or to keep you off the beach when the rubber band quits. Gives great options and the most proven road to holding .. long scope. Many probably scrimp on length of their all chain rode so it's not redicoulsly heavy. That leads to short scope in deep water. Good point.
But if you've got an all chain rode that's short it's easy to just add 100' or so. Of course then it's not an all chain rode and some would'nt want to be known as one w/o an all chain rode. It's partly social.

 

[Art]

I did Art,
Yes the longer the rode the better. For scope in deep water or to keep you off the beach when the rubber band quits. Gives great options and the most proven road to holding .. long scope. Many probably scrimp on length of their all chain rode so it's not redicoulsly heavy. That leads to short scope in deep water. Good point.
But if you've got an all chain rode that's short it's easy to just add 100' or so. Of course then it's not an all chain rode and some would'nt want to be known as one w/o an all chain rode. It's partly social.

Unfortunate that some boaters make decisions in regard to what others may think... Personal insecurity - for sure!

I've anchored boats with all chain and boats with lead chain fastened to line. IMO, ample lead chain, good line, and enough scope let out are the best ingredients for anchoring small to medium sized boats. Therefrom a good quality anchor holds well and weight of rode (enough for correct scope) does not weigh the bow down.

 

[waddenkruiser]

But if I was building a new boat I'd huck the 1/4" chain and use about 50' of 3/8ths and 200 to 350' of line depending on location. But not all chain.

Eric, I'm not sure whether I would do so.
If there is a chain of appropriate strength and length available for my anchoring needs and if I could afford the weight of it I would go with an all chain rode also in my new to built boat.
Yes, the thick chain + rope combo of same weight outperforms with regard to holding force at ultimate catenary.
On the other hand there are some disadvantages IMO, e.g. the reduced holding force margin till stiff rode condition and especially the reduced ability to store energy in the rode as long as we are not beyond ultimate catenary. Only in shallow waters the combo has an advantage in the energy criteria. But I don't want to be in shallow waters when I have to rely on that my rode is able to handle high dynamic loads (they come typically together with a tendency to high swell) without going beyond ultimate catenary. I would prefer in those situations to have a bit more water under the keel to avoid even higher swell due to ground effects ... (not the right words?)

However, I can relax myself. I'm not going to built a new boat (lack of money and in addition we've got already a nice one). And on our boat I'll not change from all chain to combo since our windlass is doing fine, no need to replace it, but it can't handle a rope.
For the time being we will stay with all chain + snubber if needed. Or eventually a 24 mm diameter rope as an extension if we anchor in deep water where our chain is not long enough to ensure a low slope angle in stiff rode condition ...


best regards / med venlig hilsen
wadden

 

[FF]

"Few agree w me here but I think saving weight on any pleasure boat is worth doing ".

With only 3 HP required for a "ton" (2240lbs) of boat to cruise , and perhaps 15 HP from a gal of fuel.

Saving 1/5 of a GPH makes it a hard sell!

Most cruisers carry 3 or 4 sets of anchor gear , and 1/5 of a GPH is a small price for insurance

 

[Nomad Willy]

Well wadden if you put an extension on your chain rode it will then be a combination rode. What I've been putting forth as the ideal rode. I'm going to check and see what chain size options I have w my 5/8ths Brait line for a combo rode gypsy. I of course would be adding chain .. not line and on the other end.

Speaking of the gypsy could'nt you just get a different gypsy wheel that does line and chain? Then tack on 100 or 200' of line. That would be pennies compared to a new winch. If you had a power loss on a windward shore it would be a very welcome feature.

 

[Nomad Willy]

FF,
Yes that's true. But if done over and over one will eventially wind up w a wallowing TT .. Tub Trawler.

Adding weight to one's anchor is clearly beneficial .. and worth doing especially if one's anchor is on the light side. But adding weight to an anchor rode that has little or no benefit dosn't pay.

 

[Paul Swanson]

I‘ve finished my homework now. It was a nice engineers exercise and I will share the results although I realized that Paul has already given the answer. (Hope you will find additional input helpful.)
Recalculating Pauls data I’ve got exactly the same figures – thank you Paul, it gives me confidence in my calculation.



Wadden.

Very nice. You also calculated the energy stored in the catenary, which I did not do. Doing it in my head, I think a 10,000kg boat at about 2 knots has a kinetic energy of about 6000 J. My analysis is for a static load but, of course, the dynamic (surge) loads can add considerably to this. In addition there is the hydrodynamic energy loss as the chain moves through the water as it straightens. I don't know how to calculate this but it appears the next step is to work on the surge loads.

Paul

 

[Nomad Willy]

How does the energy stored in a stretched nylon line compare to a chain hanging in a catenary state? One thing is obvious and that's that the nylon can stretch when the chain is still on the bottom and when the rode is pulled straight.

 

[waddenkruiser]

Paul,
I considered only the potential energy of the lifted chain by integrating the mass elements along the catenary. I'll try to send you the formula by PM.
IMO we can neglect the surge or hydraulic energy which is basically dissipated, since it should be comparably low due to the relative slow chain movement through the water.



best regards / med venlig hilsen
wadden

 

[waddenkruiser]

Eric,
the nylon will only be stretched if there is a force pulling at the rode. And if there is a force the chain will also start to lift from the ground. From that point of view no difference IMO.


best regards / med venlig hilsen
wadden

 

[caltexflanc]

It seems the whole point of this thread is for someone to rationalize not having an all chain rode. Of course it is human nature to do so when one is not capable of making something happen. I'm as guilty of that as anyone. But the benefits of all chain especially for larger boats spending a lot of time at anchor in varying wind, current and sea conditions is well documented and time tested.

 

[waddenkruiser]

Well wadden if you put an extension on your chain rode it will then be a combination rode. What I've been putting forth as the ideal rode. I'm going to check and see what chain size options I have w my 5/8ths Brait line for a combo rode gypsy. I of course would be adding chain .. not line and on the other end.

Speaking of the gypsy could'nt you just get a different gypsy wheel that does line and chain? Then tack on 100 or 200' of line. That would be pennies compared to a new winch. If you had a power loss on a windward shore it would be a very welcome feature.

How does a wheel of a windlass look like if it can handle chain and rope?
Ours has two different wheels back- and starboard, backboard for rope, starboard for chain, in between the gear. Since the outlet of the chain locker is on starboard I have no idea how this windlass could handle a combo rode. And if I'd use a combo rode not as an emergency extension but as my standard rode the rope would be spliced to the chain, so it must be stored in the same locker as the chain.
So, how does a windlass or its wheel look like if it is suitable for combos?


best regards / med venlig hilsen
wadden

 

[psneeld]

The standard looking wildcat (if that's the term you use for chain wheel) with deeper grooves in it so that when it comes to the fiber portion, it wedges itself into the grooves without slipping out (most of the time).


Line size and wear is critical in many.

 

[waddenkruiser]

It seems the whole point of this thread is for someone to rationalize not having an all chain rode. Of course it is human nature to do so when one is not capable of making something happen. I'm as guilty of that as anyone. But the benefits of all chain especially for larger boats spending a lot of time at anchor in varying wind, current and sea conditions is well documented and time tested.

Not sure about the intention of anybody. IMO we should be careful with estimations.

There are pros and cons for all chain and for combos as well. At the end everybody has to decide which setup is serving his particular needs best.
I can remember the good experience we've made with the combi rode on our first boat. It was a 20+' boat and we've had difficulties to store the anchor and the 10' chain + 100' rope combo in the tiny locker at the bow. But it did its work pretty good and we've had great times ...
Last summer I joined a sailing trip in the Baltics on a 44' SY. Again (for weight reasons) the anchor rode was a chain + rope combo. It was performing well.
For the time being we enjoy the ease of handling and the shock absorption capability of our all chain rode. And we would never change it because we feel it is the optimum setup for this boat and our anchoring habits.


best regards / med venlig hilsen
wadden

 

[waddenkruiser]

The standard looking wildcat (if that's the term you use for chain wheel) with deeper grooves in it so that when it comes to the fiber portion, it wedges itself into the grooves without slipping out (most of the time).


Line size and wear is critical in many.

O.k. So the rope has to be of similar size as the chain. Do then the load capacities fit together?


best regards / med venlig hilsen
wadden

 

[markpierce]

On my earlier boats (fiberglass auxiliary sailboats), the rode was nylon rope with a short length of chain adjacent to the anchor. Rope was much easier to handle by hand compared to chain, and the chain required special handling to avoid damaging the boat. With a windlass (leastwise on my "heavy," steel cruiser, all-chain is a winner.

 

[ranger58sb]

So, how does a windlass or its wheel look like if it is suitable for combos?

The middle/deepest channel of ours is shaped like a sine wave -- or a traveling snake? -- and then size matters. Our gypsy is specifically sized for 5/16" chain and 5/8" rope, for example, although there may be some slight deviation allowed around those specs.

-Chris

 

[Art]

A Story:

This baby pictured is exact replacement to the originally installed windless that is still currently working on our Tolly - but, after 39 years of yeomen service it's greatly in need of replacement/refurbishment. By replacing with this windless I can continue keeping our classic 1977 Tollycraft in its original condition.

I found this like-new windless a while ago on Craigslist; packaged as brand new, never out of box except for some one having taken a look. Cost was throwback to yester year too... $400 cash!! All items were with it including unblemished cover. I called the manufacturer and they were astounded it was in this condition; as well they have most parts (in the back room - lol; if ever needed...) So, I figure when I change over to my new (old) one maybe I can restore the old/old windless as a great spare. These type of 'old-school' windless require on-site/hands-on supervision and some power by Armstrong. But, after all, that's another one of the ways I stay in good-condition/i.e. young!

 

[Nomad Willy]

Art,
Here is mine bought for $400 new. Makes lots of noise w it's planetary gears but is very powerful for it's size.
Wish I could send it back though as the line pulls to port strongly or crosses over itself. I feel it must be due to the flat (w turned up ends) drum. Yours (not seen in the pic) is a nice curved saddle drum.
Those Power Winch units are all over the place .. almost as common as Danforth anchors.
Speaking of old original equipment here's Willy's foredeck when we got her. I think this configuration is as new. I still have that 13lb Danny anchor. It has forged shank and flukes. If I sell Willy I'm going to keep that one. Deployed it numerous times when other anchors wouldn't set (as in hook up w the bottom). It always did! I know you like Danny anchors.

 

[Art]

Art,
Here is mine bought for $400 new. Makes lots of noise w it's planetary gears but is very powerful for it's size.
Wish I could send it back though as the line pulls to port strongly or crosses over itself. I feel it must be due to the flat (w turned up ends) drum. Yours (not seen in the pic) is a nice curved saddle drum.
Those Power Winch units are all over the place .. almost as common as Danforth anchors.
Speaking of old original equipment here's Willy's foredeck when we got her. I think this configuration is as new. I still have that 13lb Danny anchor. It has forged shank and flukes. If I sell Willy I'm going to keep that one. Deployed it numerous times when other anchors wouldn't set (as in hook up w the bottom). It always did! I know you like Danny anchors.

Hey Eric

Yup - Curved saddle drum. I'm surprised the makers of yours did not have curved drum also.

Yup - Power Winch models all over the place. None too much like my old-school model for new ones though. That old baby is a powerful biitch; three to four wraps of the line, then held taught while pulling away from winch, and if anchor is too stuck nose of boat begins to go way deeper into water! I was brought up pulling anchors with similar Power Winch apparatus.

Yup - I do greatly appreciate Danforth anchor design; another item I was brought up using. I believe that Fortress anchor design (i.e. Danforth on steroids - lol) is a good bit better than the orig "Danny" due to weight reduction and its choices of 33 or 45 degree shank to fluke angles for sandy and/or soft-mud bottoms.