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Old 02-11-2012, 17:01   #1
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Bow Roller Bolted to the Stem Plate

I'm looking to mount a bow roller on my Tartan 30 but the foredeck is very crowded. I was looking around and found an anchor roller that bolts onto the front of the stem plate. It looks like a great idea but I'm worried about the load that hauling up an anchor and chain would put on the stem plate and forestay. Has anybody had any experience with these or any opinions? It sure would be an easy install and it'd allow me to keep my chocks up there. I just haven't seen this on other boats and wonder if there's a reason why. I added a couple pictures from the manufactures website.
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Old 02-11-2012, 17:28   #2
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Re: Bow Roller bolted to the stem plate

My concern would be lateral stability and how much lever force there would be when weighing and stowing the anchor or riding at anchor with the rode over the roller. A more thoughtful design might work.
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Old 02-11-2012, 18:03   #3
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Re: Bow Roller bolted to the stem plate

Quote:
I'm worried about the load that hauling up an anchor and chain would put on the stem plate and forestay. Has anybody had any experience with these or any opinions?
You don't haul up an anchor. You lift it out. Most windlass won't pull an anchor free and you don't use them to do so. You need the boat to break out a well set anchor loose then you lift the chain and anchor back on board. When the anchor is set you transfer the load off the bow and onto the snubber attached to the boat not over the roller. A windlass within your size class isn't going to pull more than 700 lbs.

The real load would be breaking out the anchor and that usually is not a shock load as you are moving the boat slowly to use the mass of the boat to unset the anchor. Again the bow roller is not carrying the load.

The only other situation is if you decide to ram something and then all bets are off.

I think you could attach the bow roller as you indicate provided there is something solid enough behind it that would spread the load up and down as well as to the sides using through bolts and backing plates.
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Old 02-11-2012, 18:16   #4
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Re: Bow Roller bolted to the stem plate

On smaller boats I've just that same bow roller installation as the OP is suggesting - and - on almost all of those boats the bow roller bracket/plates end up twisted laterally port or starboard. The cause is the thinness of the plate steel used combined with the lateral overload (left or right) when the boat veers to one side or the other of the anchor.

The anchor rode ends up leading off perpendicular to the axis of the roller bracket and either the rode jumps off the bow roller or the whole bow roller system gets twisted left or right. One additional problem is all this left and right twisting loads end up flexing and loosening the attachment bolts for the bow roller system. Then water starts migrating into the bow of the boat or the hull.

I think the optimal installation would be horizontally to the deck/stem piece surface rather than vertically to the hull. Even with my own anchor roller commercial systems that are bolted horizontally to the bow platform, I had to have 1/4 inch narrow strips of stainless steel welded to the outside of the bow roller frame to stiffen it when side loads tried to bend/twist the thing left or right.

All in all, I was very unhappy with the commercially offered bow roller systems and wished I had simply had my own design welded up out of much thicker and stronger stainless steel plate.
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Old 03-11-2012, 04:39   #5
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Re: Bow Roller bolted to the stem plate

Greetings and welcome aboard the CF, SlugmasterP.
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Old 03-11-2012, 04:50   #6
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Re: Bow Roller bolted to the stem plate

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Originally Posted by osirissail View Post
On smaller boats I've just that same bow roller installation as the OP is suggesting - and - on almost all of those boats the bow roller bracket/plates end up twisted laterally port or starboard. The cause is the thinness of the plate steel used combined with the lateral overload (left or right) when the boat veers to one side or the other of the anchor.

The anchor rode ends up leading off perpendicular to the axis of the roller bracket and either the rode jumps off the bow roller or the whole bow roller system gets twisted left or right. One additional problem is all this left and right twisting loads end up flexing and loosening the attachment bolts for the bow roller system. Then water starts migrating into the bow of the boat or the hull.

I think the optimal installation would be horizontally to the deck/stem piece surface rather than vertically to the hull. Even with my own anchor roller commercial systems that are bolted horizontally to the bow platform, I had to have 1/4 inch narrow strips of stainless steel welded to the outside of the bow roller frame to stiffen it when side loads tried to bend/twist the thing left or right.

All in all, I was very unhappy with the commercially offered bow roller systems and wished I had simply had my own design welded up out of much thicker and stronger stainless steel plate.
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Old 03-11-2012, 06:57   #7
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[QUOTE="osirissail"]

I had to have 1/4 inch narrow strips of stainless steel welded to the outside of the bow roller frame to stiffen it when side loads tried to bend/twist the thing left or right.

All in all, I was very unhappy with the commercially offered bow roller systems and wished I had simply had my own design welded

Agree I did as you say welded plate to the sides and added a lower plate that bolts through the gunnel. On mine the only attachment point was 2 bolts through the deck on the aft end. Maybe the intention is to provide a base and we get to beef them up to a better standard.
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Old 05-11-2012, 15:48   #8
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Re: Bow Roller Bolted to the Stem Plate

Would the twisting and lateral movement be an issue if I'm only using it to drop the anchor and lift it out? The rest of the time while at anchor I'll have the nylon rode running through chocks and cleated off.

Pblais I think that's what your getting at right? That the roller isn't meant to be used while at anchor. If that is taking the stress from the movements of the boat I could see how there could be problems with bending and twisting.
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Old 05-11-2012, 16:00   #9
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Re: Bow Roller Bolted to the Stem Plate

My B393 came with only one anchor roller, the one on the starboard side. We removed the stemhead fitting and got another one welded on. Very strong and does not look as if it's just an add-on.

Another view.
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Old 05-11-2012, 16:47   #10
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Re: Bow Roller bolted to the stem plate

Quote:
Originally Posted by Pblais View Post
You don't haul up an anchor. You lift it out. . . .
The real load would be breaking out the anchor and that usually is not a shock load as you are moving the boat slowly to use the mass of the boat to unset the anchor. Again the bow roller is not carrying the load. . .
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SlugmasterP Would the twisting and lateral movement be an issue if I'm only using it to drop the anchor and lift it out? The rest of the time while at anchor I'll have the nylon rode running through chocks and cleated off.

Pblais I think that's what your getting at right? That the roller isn't meant to be used while at anchor. If that is taking the stress from the movements of the boat I could see how there could be problems with bending and twisting.
Here is where reality and theory clash. When "at anchor" you normally have a bridle attached to the anchor rode and also attached to either the bow cleats or a Samson post so that loads imposed by wind/waves or current are not directed through the portion of the anchor rode between the "bridle" and the windlass but instead transferred to said Samson post or bow cleats.

Then comes "weighing anchor" or "up the hook" time. The bridle is removed and the anchor rode is established back over the anchor chock roller assembly. Then the anchor rode is hauled in by "whatever" means until the anchor is nestled back in the chocks.

Except - when the anchor is firmly and dastardly buried in the sea bottom, usually in clay or some seriously deep mud. [This happens about 2 or 3 times per year to me]. Also things can get really nasty when the anchor get tangled in sunken boat wreckage or abandoned mooring chains. Then retrieving the anchor becomes an extreme ordeal and loads are imparted to that commercially made bow anchor chock/roller system that it is simply not strong enough to handle.

Typically, veering is employed - driving the boat over the anchor and off in a side direction - to try to dislodge or loosen the anchor. Here is where the side loads generated in this maneuver twist and bend the thin side plates.

Or, you drive the boat over the top of the anchor and straight ahead attempting to rotate the anchor vertically to the opposite direction and break it free. Here the buoyancy of the boat is used to cause the bow to "dip" and then yank vertically on the anchor rode/anchor. Here is where the weak side plates and even the bottom plate and bow attachment bolts are stressed and bent.

On smaller boat - under 35 ft (12m) I have seen quite a few bent and twisted bow anchor chocks. The frustration of not being able to promptly raise the anchor when "it is time to go" frequently results in these less than optimal techniques for retrieving a stuck/buried anchor being employed.

Patiently putting a vertical load on the anchor rode with gentle boat movement (sort of, wiggling around) over time will work the anchor free except when it is caught in sunken debris. I have spent as much as an hour and a half working an anchor out of the mud in Luperon, D.R. after it has been "down there" for several months. One way to put a vertical load on the anchor rode and not on the anchor chock/roller is to use a spare fore halyard from the main mast and attach it to the anchor rode. Then winching in the halyard puts a purely vertical pull on the anchor rode and with time wiggles the anchor free - or even in one case, raises the sunken vessel part that your anchor has grown an intimate attraction for.

So yes, you can go years without overloading one of those commercially made anchor chock/roller systems - or - you can twist the heck out of it during one frantic "got to go now" moment.
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Old 05-11-2012, 17:22   #11
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Re: Bow Roller Bolted to the Stem Plate

Quote:
Pblais I think that's what your getting at right? That the roller isn't meant to be used while at anchor. If that is taking the stress from the movements of the boat I could see how there could be problems with bending and twisting.
Yes it was. We have a bowsprit and you just don't load those up on purpose either if you can help it The basic setting and unsetting the anchor usually is a small load but once set and you feel snug as a bug you set up a bridle then all of a sudden a storm or what ever the loads get high. Time wise you know what it is when you set the hook but then you stay a while anything can come up. When leaving being impatient is always a bad thing. When it won't break out under normal conditions you need to stop and rethink! It's one of the corollary rules about not ever being in a hurry on a boat!

As noted above you can get the odd situation and suddenly the light weight bow roller gets loaded up too much. The problem is it could be possible that nothing you could do would be strong enough. You go head on into a concrete bulkhead and stuff will break no matter what. It comes down to what you do on purpose not what is possible.

You don't use a windlass like a kedge to pull the whole boat. They don't do that very well and a good one will blow the thermal fuse and stop you cold (know how to reset the breaker / fuse).

I consider the windlass to be the most dangerous bit of gear on the boat and I never let anyone else but me risk losing a finger. I did get the tip once on one finger and it wasn't pretty yet I saved the whole finger with no scare and regretted the accident for about a month. Chain on a gypsy is a mean battle.
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Old 06-11-2012, 00:41   #12
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Re: Bow Roller Bolted to the Stem Plate

Hi SlugmasterP,

Rex Hear, I don't know if it helps but we have been producing heavy duty bow roller arrangments now for many years,Yachts, commercial work boats and pleasure boats never had one bend, you can view these on our web site, we do not have a distributor oin your part of the world but may be of interest. click on bow rollers left hand side of home page.

Regards.


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