Anchor roller design questions

[Chris & Lenore]

I have a commercial roller that's about 2 inches wide and 15 inches long.

I realize it needs to overshoot the bow about 4 or 5 inches to provide enough clearance for the Bruce it will be carrying.

My thoughts on how to mount and provide support are similar to what Bob Hussey did.

I plan on a metal strip 2 inches wide and about 24 inches long that will support the roller.

It will overshoot the bow the required number of inches and then bend downwards to match the bow angle (and also be bolted to the bow "V").

The original stem head will be removed and the forestay will attach directly to one side of the roller "U channel".

There will be a decent size backing plate on the underside too.

My question is around choice of material. I can use stainless steel but what thickness? Price goes up substantially between .188 and .250 While the quarter inch thickness seems robust, is it overkill? The roller itself appears to be made from much thinner material. Given that this "platform" will be in air space for 4 or 5 inches, will .188 be sufficient thickness?

The other option is aluminum. I could use 1/4 inch 6061T6 or 7075T6 for about half the cost of stainless.

Any thoughts on this?

 

[centerline]

you really need to have some shear support for it to be strong.
if you used something about 14 gauge with 3/4 to 1" legs formed into it on the sides, it would be strong enough, and then use a piece of .250x1.25 for the support leg....

to use a piece of flat bar and bend it to the shape you want, it has no structural stability, either sideways or up and down or twisting.
with legs formend into it (like a piece of channel iron) it gives it great strength in all directions. with if you were to use 1/8"thick material and have it formed so it has 1.25 high legs, and around 3.25-3.5 inches wide, finished size, it would be strong enough to just mount to the deck without a lower support leg.
I think your deck would be the weak link then.... but that would also depend on how long the entire piece is, and the ratio of how much is attached to the boat and how much overhang you have.....

 

[Sumner]

Maybe think about spending more on the roller so you don't have to beef one up.

The other thing that I would do if I made my rollers again would be to make them wider than I did with wider rollers on them. I think mine (I'm not home) are at least 2 inches and might be 2 1/2 inches wide. You then need to think about shackle sizes that will easily move over the rollers and fit between the sides and 2 inches might prove to be a problem. Not sure what size shackles/chain you are running now but consider that at some point you might want 5/16 chain with the appropriate shackles.

Sum

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[Chris & Lenore]

Hmm - Centerline's comments started me thinking. The strip of metal I'm talking about is really just to provide a "platform" ( with leg) for the front third of the anchor roller. My anchor roller is a regular "U" channel but would have too much "leverage" if just bolted to the deck.

So, my thought is now - why do I feel the need for a strip of metal under it at all? If I add a leg from the unsupported front to the "V" of the bow (and bolt it in place), then nothing is "unsupported". A decent backing plate would ensure the remaining leverage is spread out.

It may be that a piece of hardwood or HPDE under the roller assembly is a good idea too. My original design required that I grind down the "ridge" at the bow so things fit flush to the deck. With wood or HPDE, I can shape it to fit over that ridge. I think Oreana 123 did it that way.

Now if only the weather cooperates...

Chris

 

[redhead78]

some ideas and pics on add anchor bow roller

I had same thoughts, my 38 jeanneau, has a roller furler right in the center, and had no room to leave an anchor out. To deploy I had to lift out of the locker, and feed down between the bottom rail of the bow pulpit, and the furler.You would have a hard time handing a basketball through this space....Here are some pics of what I did last weekend,I used 2 ets of backing plates under the inside of the deck, and 2 side bolts u can not see into the side of the existing bow piece. You could also add a small triangular gusset attached to the underside if you think u need more beef. I will post better pics after the weekend... Red

 

[centerline]

Hmm - Centerline's comments started me thinking. The strip of metal I'm talking about is really just to provide a "platform" ( with leg) for the front third of the anchor roller. My anchor roller is a regular "U" channel but would have too much "leverage" if just bolted to the deck.

So, my thought is now - why do I feel the need for a strip of metal under it at all? If I add a leg from the unsupported front to the "V" of the bow (and bolt it in place), then nothing is "unsupported". A decent backing plate would ensure the remaining leverage is spread out.

It may be that a piece of hardwood or HPDE under the roller assembly is a good idea too. My original design required that I grind down the "ridge" at the bow so things fit flush to the deck. With wood or HPDE, I can shape it to fit over that ridge. I think Oreana 123 did it that way.

Now if only the weather cooperates...

Chris

Chris,
if the anchor roller you have is only 15 inches long, it wont be long enough to get the anchor out away from the boat. very likely that it mat strike the hull during retrieval if you try to draw it up over the roller.
if yo utry to stick it out far enough, you wont have enough structural support even if you add a large backing plate.
the support has to go back on the deck far enough to separate the stress areas.... the aft end of the "roller support" will be trying to lift up and away from the deck, while the front of it, near where it leaves the deck to go out to the roller, will be trying to push down into the deck.... you need these two stress areas to be apart from one another so you can control each area individually.

if you dont separate them and they are too close together, you can NOT control them and they will work together to try and peel it all out of the deck..... a backing plate may prevent instant failure, but cracking of the glass and gelcoat as it tries will be the beginning of the complete failure of it.


when i built mine, i fabbed a piece kinda like the anchor roller piece only wider and a bit longer... then mounted it solidly to the deck. that gives a strong foundation to mount the anchor roller to with it hanging out farther forward like it needs to be to be practical....

 

[Chris & Lenore]

So that is a good question - how far should the roller part be from the hull?

I have seen many at about 4 or 5 inches (with a Bruce) and other (like Oreana123) that project a good foot.

I assume that "more is better" but what is the feeling on minimum practical?

I had another look at my roller assembly and the distance between supports would be about 12 inches. The front leg bolted onto the V of the bow will take the weight of several people on it (if not more). But that assumes an overhang that places the roller about 5 inches past the front lip of the boat. The geometry is almost identical to Bob Husseys.

It snowed last night!!! Guess I have time to figure this out properly...

Chris

 

[THECUSCUS]

Chris, here a pics of my roller. I have a 1/4" alum backing plate, cut to the inside shape of the bow area. The bow is probably one of the stiffest, strongest areas on our boats. The glass is thick, and curves and corners add strength. Put the anchor you are going to use into the roller, and place the roller on the bow and see how far out it needs to go so the anchor doesn't hit the hull. The tip of my anchor actually sits rearward of the front edge of the bow, but I secure the anchor well and it doesn't move. I don't think the leverage is going to be an issue (unless its sticking out a foot or two). The important thing is to use the proper amount of scope when anchoring, so that the angle of your rodeos not pulling close to straight down on the end of the roller. And a good bit of chain will help. I use 25' of 5/16". Oh, and don't worry about the short overhang, the angle of the bow gives you plenty of room, unless you motor over your anchor. I always pull my rode in by hand so the anchor is always out in front and don't put the motor into gear until the anchor is in the roller.

 

[Sumner]

Chris are you thinking of a vertical support coming up from the bow to the front of the roller? That will help but also consider some side to side loads as the boat swings on anchor.

I know you guys like longer trips and are planning more so I'd also consider putting the roller on in such a way that you could possibly add a second down the road. We really like having the second roller and often put two anchors down as it is quick and easy to do with our anchoring gear.

I just added a second bow roller to the Endeavour and a manual winch as we wanted 2 anchors handy and available on the boat. The old roller ...

...on the right rode up on that forward deck plate and bolted down to the deck in the back causing it to twist, kind of like the raised part on the Mac. I ....

...cut some plates and put then under both rollers so that they now sit flat. Did something similar on the Mac to get the roller over the ridge, but it was built into the roller base.

Here ....

... the two rollers are in place and here...

...the anchors are on and the manual winch is mounted.

The rollers have quite a bit of overhang, but are so well built that I can stand on the ends of them with no flex.

The winch pivots side to side to work with either anchor and there are two chain lockers. The forward one is under the back right side of the winch and the chain goes below just forward of the vertical support. The other chain locker is the one you see the chain going down into and that one is under the hinged hatch.

 

[centerline]

the bow area IS strong... when I removed the nav light, the deck thickness was about 5/8" or maybe a bit more. but the farther back you go the weaker it becomes.
you may not need or want a tipping roller setup. i think with a delta anchor, the design of it is self deploying, but not all anchors are. my roller setup was designed around one that is not on purpose.... because want it to self deploy any anchor I choose to use.
the first three pics are of my setup on the the 21 I had and it worked great. I had to add a bit of support under the edge as it left the deck, because with the first install, it made cracking sounds.
the basic anchor roller shown is almost identical to the one you have, except i welded a tube to the bottom of it for a pivot.... i had the base piece formed so it would catch enough deck to be solid, and then drilled holes where i needed them.
the anchor cleared the rail by 1 inch when retrieving, but it was already stabilized on the roller by the time the clearance got that tight.
with it being off center, you will never notice any difference than if it was straight out the front....

the last 5 pics show the setup on my 25...
its a simple design. I knew I was going to move my bow/nav light to the hull, and if i did that it would free the deck for a heavy duty stem fitting that I could incorporate an anchor roller into and have more adjustment for the forestay....
NOTE... for an anchor roller, the lower support to the hull may be not be needed, but as I was intending to attach the forstay and jib to it, i needed strength upwards also...and it helps with strength in all directions.
the anchor does stick out farther than necessary, but on the roller part there is another pivot hole that I can use to move it rearward if i feel the need, but i want the clearance, and the stress is close to the deck so i dont see the need to yet... but with a delta or bruce anchor, it may stick out way farther than needed on the current setting because the balance of the anchor may be different.
for size reference, the danforth anchor shown in the last 4 pics is 30"long. the flukes are 16".... so you can see i have a lot of clearance.

it may all seem like overkill, and probably is, but I come from the school of thought that dictates that a good foundation is the key to strength/security, and i have the ability and tools to make it look nice and be strong, so why not?

 

[oreana123]

The bow area will be even stronger if you fab up a backing plate and install it under the deck and spread out the affected area. I camped on my boat last night, about 100 feet of rode out and stern tied to a friendly tree. Slept like a baby because I know the boat isn't going anywhere.

 

[Timo42]

I mounted mine without much trouble backing plate under the deck and filled in the glass under the bracket, I don't intend to leave the anchor line on the roller while at anchor, there is a fairlead on either side for that, so no extra reinforcement needed. . The claw anchor curls around the bow without contacting it.