Do I need a back plate to my new anchor rolling?

[raintoomuch]

My 30' Soveral does not have a anchor roller. I wanna attach my windline that a friend gave to me. I have a Danforth (not sure how big, came with boat) and a 35lb Delta plow.

Do I need a back plate? What material should I use, and how much of it should I use? Is there anything I should know about?

I plan on living on the hook, so yes, I need it for storms and everything in between. Finding stuff info for Soverals is difficult and I find most people don't know much about them.

[thinwater]

Originally Posted by raintoomuch

My 30' Soveral does not have a anchor roller. Attachment 156967Attachment 156968 I wanna attach my windline that a friend gave to me. I have a Danforth (not sure how big, came with boat) and a 35lb Delta plow.

Do I need a back plate? What material should I use, and how much of it should I use? Is there anything I should know about?

I plan on living on the hook, so yes, I need it for storms and everything in between. Finding stuff info for Soverals is difficult and I find most people don't know much about them.

Not knowing the structure of the boat we have to make some conservative suggestions.

First, you probably do need a backing plate. The pull could be as great as 1500 pounds, assuming you use nylon rode. However, this pull should be taken by a deck cleat when anchored. That said, the roller can take some good tugs.

Second, lacking better information, a simple way to estimate loads is to go by fastener size. The assumption is the the designer knew something. In this case, a fiberglass backing plate generally needs to be about 65-75% of bolt diameter thick, and an aluminum or stainless plate about 40-60% of bolt diameter thick, depending on the underlying structure. If the bolts are 5/16" dia, 1/8" metal to 1/4" fiberglass is about right. Use standard bolting washers in addition.

Third, the backing plate should extend at least 5 boat diameters beyond the fasteners and beyond the footprint of the equipment.

Finally, the backing plate needs to make good contact. If the surface is uneven, bond the plate with either thickened epoxy or polyurethane sealant to spread the load.

Fender washers are NOT backing plates. They bend into cones as soon as the load comes on. Heck, you can bend them with pliers.

There are many other correct answers.

Good luck!

[raintoomuch]

For the record, I'm an idiot when comes to boat building terms and boat terms in general. I have three 1" bolts Marine whatever grade and no idea the fiberglass of measurements.

[redsky49]

A backing plate, roughly the same size of the anchor roller mounting base, 1/4" thick aluminum, would be overkill and precisely what I would install. Protect against any dissimilar material corrosion. Caulk deck penetration carefully.

Redsky is right. And there is another way.

You can also use timber for a backing plate, but you must thoroughly coat it with epoxy, to seal it. Then, when you drill the holes for the roller, seal the insides of the holes with runny epoxy, so they are sealed to water before you put the bolts through. This will keep you from having the potential problem of dissimilar metals corrosion, which redsky told you to protect against. What you choose to do will depend on what you have available. Sometimes there's pretty good scrounging in boatyard dumpster bins, sometimes not. If the bow of your boat is curved for draining, you may want to epoxy in the backing plate with filler, a really stiff mix, to make a good sealing surface. You mix it up, thicker than mayonnaise. You will want a stick or something to push the plate tight to the inside of the hull, while the epoxy sets; and it should be scrupulously cleaned beforehand: sand off any loose stuff, and wipe with lacquer thinner or acetone till the rag is clean, keep turning it.

It is a good first project for you. You may want longer bolts, but wait till the backing plate is in before you measure, you have to allow for washers, too. Smear plenty of caulk over the top of the hole.

When you actually install it, it can help a lot to have a friend with a paper towel or two below, to catch excess caulk, and to hold the nut with the wrench. Bye the bye, there's no real reason you can't put them through from the bottom, if you prefer, but you will need someone to support the bolt then, till you've tightened it. This will allow you easier removal of the roller in the future. Most things on boats are not forever deals.

Ann

[UNCIVILIZED]

1/4" aluminum or G-10, a bit thicker if you like. And 25%+ larger than the footprint on deck of the roller. Keeping in mind that the loads at the back end of the roller can be fairly strong, due to the lever arm involved, so a bit of extra backing plate in said area couldn't hurt.

The other thing though is that you'll want to ensure that all of the cleats, especially on the foredeck have good backing plates. And if you can use one piece of material for all of these things, so much the better. Especially if you use some thing like G-10 or FRP (fiberglass) plate & bond it to the underside of the deck with structurally thickened epoxy. Milled or chopped glass fibers works well for this, & for structurally bedding or bonding things. That way you have one big monocoque structure.

Also, it's good to taper (bevel) the edges of backing plates, so as not to create stress risers (hard points) where they end. As the taper eases the transition of the loadings from the areas with the backing plate to those without. Since obviously the section with the backing plate is stronger & stiffer.

Oh, & make sure that you're not mounting high load items in areas that have cores like balsa. As, sadly, they're prone to getting wet, & then soft & squishy, negating their structural properties.

[Suijin]

I would not use wood, even impregnated, in the anchor locker (an inhospitable environment for most materials) for the simple fact that there are better materials to use for the job. You can buy sheets of G-10 on Bay that would be superior. Cut it to size with a bi-metal metal blade with a jigsaw and drill out the holes. Done.

Looking at your picture you may need longer bolts depending on the thickness of where you are mounting it and adding in the backing plate thickness. Factor in a fender washing and a lock washer (for 5/16" I would add a quarter inch to assure you can get the nut on). When tightened down, the bolt needs to fully extend through the nut threads.

[SVTwilight]

Originally Posted by redsky49

Redsky is right. And there is another way.

You can also use timber for a backing plate, but you must thoroughly coat it with epoxy, to seal it. Then, when you drill the holes for the roller, seal the insides of the holes with runny epoxy, so they are sealed to water before you put the bolts through. This will keep you from having the potential problem of dissimilar metals corrosion, which redsky told you to protect against. What you choose to do will depend on what you have available. Sometimes there's pretty good scrounging in boatyard dumpster bins, sometimes not. If the bow of your boat is curved for draining, you may want to epoxy in the backing plate with filler, a really stiff mix, to make a good sealing surface. You mix it up, thicker than mayonnaise. You will want a stick or something to push the plate tight to the inside of the hull, while the epoxy sets; and it should be scrupulously cleaned beforehand: sand off any loose stuff, and wipe with lacquer thinner or acetone till the rag is clean, keep turning it.

It is a good first project for you. You may want longer bolts, but wait till the backing plate is in before you measure, you have to allow for washers, too. Smear plenty of caulk over the top of the hole.

When you actually install it, it can help a lot to have a friend with a paper towel or two below, to catch excess caulk, and to hold the nut with the wrench. Bye the bye, there's no real reason you can't put them through from the bottom, if you prefer, but you will need someone to support the bolt then, till you've tightened it. This will allow you easier removal of the roller in the future. Most things on boats are not forever deals.

Ann

Rather thm coatimg timber I used 3/4" starboard and the biggest fender washers I could find.

Easy to cut and form, Great results amd no rot ever!

[skipmac]

I would stick with a metal backing plate. I pulled a dozen or more, thick fiberglass backing plates off my boat under stanchions, cleats and such. Over time they had compressed and deformed.

Since you have a SS roller and SS bolts use a SS backing plate. I think Thinwater's recommendations are spot on and how I did mine.

[Sailorbob8599]

Originally Posted by skipmac

I would stick with a metal backing plate. I pulled a dozen or more, thick fiberglass backing plates off my boat under stanchions, cleats and such. Over time they had compressed and deformed.

Since you have a SS roller and SS bolts use a SS backing plate. I think Thinwater's recommendations are spot on and how I did mine.

Good suggestion! . . . I used s.s. backing plates for all exterior hardware when I built my boat, also stainless Nylok nuts & bolts. Do NOT use regular type lock washers . . . they have a habit of breaking and allow standard nuts to come loose.

[UNCIVILIZED]

You guys are familiar with G-10 right? Some grades of it are, thickness for thickness, stronger & stiffer than aluminum. Not to mention lighter, & much easier to bond.

[raintoomuch]

Originally Posted by UNCIVILIZED

You guys are familiar with G-10 right? Some grades of it are, thickness for thickness, stronger & stiffer than aluminum. Not to mention lighter, & much easier to bond.

Tell me more about G-10. Btw, all this info makes me much more confident in the project. Makes me think I'll need new cleats too, I have little wimpy ones.

[Island Time O25]

Another vote for G-10.

I had a teak bow roller platform fail during an anchoring maneuver - two motor boat speeders came one after another and the chain load on the 30+ year old teak was too much. So with the help of my marine pro buddy I decided to re-do the whole set up. Moved the bow roller a bit aft (and no teak platform now), installed an old war horse Nilsen windlass and reinforced the forward cleats. All reinforcement was done with G-10 plate. According to my friend in the long run as a backing plate G-10 is the best solution for that area as it is the most wet area on the boat after the bilge. We glassed the backing plates to the under side of the deck and used beefy ss bolts with add'l beefy washers and lock nuts. My other friend - the boat builder - when he took a look at the new set up said laughingly that now my boat can be hoisted just by the bridle running around the cleats and the windlass. And he also said that the bow portion of the deck will be the last area destroyed on the boat in any event.

[Cheechako]

a) you will likely find you need some sort of wedge between the roller and the deck as the deck is most often not flat to the world.
b) make the biggest backing plate you can, but in that bow interior you may end up with THICK large fender washers on a couple of the bolts, depending on the room you have.
c) Dont be surprised if you have to drill another bolt hole to get enough attachment.
d) the underdeck may be lumpy You have to make shims to level things out under there for the backing plate.

[raintoomuch]

I'm sold on the G-10, I'm thinking an easy 12"x12" plate at 1/4" will do the trick. Any suggested retailers?

[redsky49]

McMaster Carr is good source. It's useful to have some of this onboard for multiple projects.