Requirement of backer board for stern cleats?

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Requirement of backer board for stern cleats?

Post by ktm_2000 »

Hi All,

I'd like to know people's opinion of the strength of the transoms in regards to installing stern cleats and if it requires a backer board.

I've been using this person's B31 transom as an inspiration for my project with the storage area in the center to allow hoses,wires, etc to come up from the bilge and am wondering about the requirement to put backer boards beneath the cleats.
https://photos.app.goo.gl/bviKG4vtb9PwxcFTA

In my project I did the inside glass on the transom core where I left 2 layers somewhat short with the thought process that I would come back later and wrap the inside transom corners with several layers of fiberglass to strengthen that area. I was thinking originally to put a board on 45 degrees to the corner and put the cleat on that because I didn't want any fasteners to show on the transom. I am thinking the complexity of figuring out that corner board plus making sure my arm could fit in behind that to attach the cleat would be to many opportunities for me to mess it up and have to do re-work.
https://photos.app.goo.gl/NusFxbEm92Yt75hc6

I am going to wrap the corner with 3 layers of fiberglass either way, do you think backer boards for the cleats are worth it?
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Confused as a 31 is not cored in the transom, sides or bottom.

None the less my 31 has the cleats built into an H blocks laminated to the hull sides.
Two upright pieces of wood having the top and bottom fiberglassed to the hull sides, center notched out for the horizontal block to be nested then fastened in. The cleats are mounted to the center block with lag bolts that go through the side panels, into the block. Center block is approximately 1-3/4 x 5 x 8". No through-hull protrusions and strong enough to snap 1/2" dock lines in the last storm.

Not as simple as through bolting and not as involved as a top hat mount as shown on the 31 you show the picture of. But you do need side panels to cover.

My .02, through bolting, may not offer the clean a look desired, but to me it is perfectly acceptable showing the boat is built no-nonsense tough instead of being built pretty.
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Re: Requirement of backer board for stern cleats?

Post by Rawleigh »

I used the existing H block and beefed it up to include a threaded backer plate for stove bolts through the cleats to thread into. The factory setup was just large wood screw.
Last edited by Rawleigh on Oct 8th, '20, 14:09, edited 1 time in total.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

Carl,

I get the concept but have not seen pics of the setup which you are describing, a google search on "Bertram 31 Stern Cleats" doesn't come up with a lot of great images.... The ones that it does come up with are where the cleats are attached to covering panels and the panels are attached to the gunnels and deck similar to how the B25 had a molded stern panel in the I/O config.
https://photos.app.goo.gl/YfeNjZNmtdaRVVJ97

I tried towing a boat once that weighed more than mine and when the towed boat went over a wake, the stern panel screws got ripped out along the bottom and it popped the engine cover open. No major damage, just the configuration was not strong enough. I ended up re-routing the tow line to go in the stern hawse pipe, back on top of the top cap and tied off to the midship cleat then tied off again to my bow cleat.

At the time the inspiration pic was posted, there was another which I didn't save which showed the bolts coming out the transom had washers and cap nuts. I agree with you that the setup is no nonsense and would be tough but I am wondering if it would be strong enough or if a backer board to spread out the load is needed. I think on my boat the transom glass (outside the bump-out which is cored) is a little under 1/2" thick
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

It isn't too much more work to add a backer plate inside so I used a strip of scrap 3/4" meranti marine plywood. It was already the width that it was, I cut 2 pieces to length and then beveled the edges.

The area where the panels will land is a little rough with a couple of high spots, I didn't want to put on grinding clothes over lunch and be itchy for my afternoon meetings. I'll take care of grinding the inside before bonding it in tonight.
https://photos.app.goo.gl/eX5FPnB7mVeKTAxa8
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Image

Rude and crude, but works well. Cockpit deck sits right under with side panel in front all clamped with cleat bolts. Lag bolts are 1/2" dia x 3 or 4" long.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

Carl,

Thank you for the image and your advice. I think I am going to go with the more simple thru-bolting method along with the backer plate inside the boat at the cost of some visual blemishes outside the boat. I'm thinking of it as a KISS situation, because far too often I over-complicate things and end up the last S.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Your calling a couple 316SS polished washers and finishing nuts blemishes, I'd call them badges of honor.


Alright, maybe badge of honor is a little overboard...but not by much.
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Hi guys,
I’d glass in an aluminum plate so it can be narrow and nice looking from the inside. That way you can pre drill and tap plate per cleats you will use, and apply teff-gel to bolts. BTW those inside gunnels took me about two weeks to fair and smooth for that open layout without panels! I know those under gunnel knees anywhere! Coosa.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

Rocky, that is an interesting idea. I have no idea where I could get the auminum stock but a neighbor is a welder and I can ask him tonight
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Yes I think the large surface area of bonding and glassing a plate into that transom would never blow out. Not even Jaws with 2 barrels on her!
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Re: Requirement of backer board for stern cleats?

Post by Snipe »

I made cleat pads out of aluminum and coosa then bedded them down under the gunnel in the stern. I also faired the cockpit out for a clean look.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

I took Rocky's advice and am going with glassing in aluminum plates to mount the stern cleats into the back of my boat. Here's a pic of the stock which came in today along with one of the B25's original stern cleats.
https://photos.app.goo.gl/kyxAjxaZRuVK9PaG7

I discussed the idea with my neighbor and went a bit thicker at 5/8" 6061 aluminum plate. The little bit more thickness will add a some more metal to bite into. My neighbor recommended alumicut to tap the holes as well as going with a finer pitch thread to get more thread area to catch on. His last recommendation was to purchase cheaper steel bolts and to cut the heads of and sharpen them to a point that way when I am glassing the panel in, the threads would be sealed an the point of the bolt could be pressed through the glass. After it cures the bolt could be removed via vise grips.

I'm going to track down drill bits, tap and bolts of all the same thread before messing with this, the last thing I want to do is drill and tap one thread then not be able to get the right pitch thread bolts in stainless.
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Nice. That will function and look great. 5/8” thickness, beefy!
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Re: Requirement of backer board for stern cleats?

Post by Yannis »

Ktm,

Aluminum is soft and the progressive pounding at the dock may take a toll on those threads.

Instead of creating threads onto the aluminum, why don't you take precise measurements of your cleats and make four real holes without threading.
Then, you could insert the bolts of your choice and reverse the slab so that the bolt threads are visible. You could then secure the cleats with nuts on the visible side.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

I won't get into the course/fine thread strength debate seeing how thread strength is not a big issue since cleat pull is 90 degrees.

I do want to mention Alum and SS do not get along in a saltwater environment, so Tuff Gel when assembling is important if you want to remove bolts down the road. Also, fine threads are not very tolerant of dirt and debris so make sure everything is clean when assembling...a little dirt or corrosion on a 1/2-20 fine thread will screw up the aluminum threads real quick. I am thinking 31 Bertram...you might be smaller with 3/8-24

LAst...if your drilling free hand do your best to make sure you go straight through, do not wander off at angles enlarging the hole. There is very little holding material with a fine thread, an enlarged starting hole gives even less.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

Carl,

I'll be honest - I'm not too knowledgeable about metalworking. I have a drill press (for woodworking) and want to get the holes drilled off the boat, hopefully that keeps them straight. I believe the screws on the original cleat were 5/16", I will check as I still have the original screws too. I know you are in the machining business and you say the thread strength is not a problem because the 90 degree pull, is it worth the fine thread then? I could see myself mucking up the tapping process more easily with fine thread and it would be easier to find a standard thread tap and bolts will be straight forward to locate.

I agree on the dissimilar metals - galvanic corrosion, when the aluminum corrodes, ions transfer from less noble metal (I took chemistry in college - get that part) so tef gel it will be.

Yannis - the boat is a trailer queen, typically tied up at a dock for 15 min max when launching or landing so no real long term progressive pounding. I would be more worried about a 1 time shock like I did when I tried to tow a @30' sailboat who lost power at the end of the cape cod canal. In a case like that, would 3 layers of 1708 set in vinylester resin hold or would 4 bolts pull out? who knows hopefully I won't be in a situation to find out.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

My concern would be the vinylester resin. To my very limited knowledge it is not the best choice as an adhesive to things other then itself. I believe epoxy resin is best for structural and joining dissimilar materials. I could be wrong though...not my area and I believe there are work arounds with prep or...

Using a drill press for holes is a wise move.

Tapping is easier with a fine thread as less material gets removed and you have the mechanical advantage of the fine thread. But you are right about trying to locate a fine thread...its a bit tougher to get started and much easier to crossthread.

As the cleats are being pulled 90, the hardware would shear before pulling out. If a direct pull, the fine thread pulls before the course, but I'd epect the hardware to fail first, especially if using SS hardware. Now if the bolts are loose...all bets are off.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

I am not as concerned about the resin which I am using as the surface area is significantly larger than the plate itself. The plates are 6x14" but I was going to place them flat on the transom and then I was going to fill gaps and edges with filler to make a nice radius to put 3 layers of 1708 starting at the edge of the transom storage part I made then wrapping the corner and going 12" around the side of the hull side. so roughly 24" on transom, 12" on hull sides.
https://photos.app.goo.gl/41ER1LJZC8KFUor76

I'm now thinking for simplicity that a standard thread pitch is the way for me to go.
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Re: Requirement of backer board for stern cleats?

Post by mike ohlstein »

The purpose of those roughly triangular hawseholes is to set the direction of pull of the stern lines in relation to the cleats. This causes the force on the aft cleats (and more importantly, their hardware) to be in shear, not tension. Since we're now talking about shear strength, the cross section of a fine thread is going to be beefier than a coarse thread, so fine is stronger. As screws tend to have relatively little shear strength to start with, BIGGER is always better. Threaded bolts are even better, lag bolts are better still.

And again, epoxy is an adhesive. Polyester (and all of the other esters) are not. A monolithic pour of polyester will be just as strong as (and cheaper than) epoxy. But when you want something to stick to your 45 year old boat, epoxy is the ticket. Accept no substitute, and don't listen to anything that anyone else tells you. "If you prep it right...." Bullshit "I've done it a thousand times..." Bullshit "It will outlast you....." Bullshit.

Just don't do it. Make your parts out of whatever you like, but when it comes time to adhere them to the boat, epoxy. Always epoxy.
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Re: Requirement of backer board for stern cleats?

Post by CamB25 »

Wow...this got complicated. Threading aluminum? Really? Even I wouldn't do that! :-D As Carl said, the threading is not important as the load is almost pure shear. You can keep this simple by glassing in a piece or two of plywood and mounting the cleat with stainless lag bolts. All you really need to do is "pin" the cleat in place.

If I remember correctly the stock cleats where not even mounted to the hull, just the hull liner (fiberboard) with a piece of plywood glued on the back side.
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Re: Requirement of backer board for stern cleats?

Post by Tony Meola »

Carl

How difficult would it be to drill and tap a piece of stainless plate? I know I tried to drill a hole in the stainless tubing on my Bimini and gave up. But flat plate might be easier. Any advice on how to do it?
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Tony -

Drilling and tapping SS Plate or any other shape is as easy or hard as you make it.

Wrong tooling, wrong speeds, feeds and drilling and tapping SS can be dam near impossible. Do it the right way and it's just another material...at least for most grades of SS, some are a bit challenging. Running a job now, 1600 SS plates that are sawcut, brought to size than 5 holes in two different sizes are drilled and tapped. Running the job very conservatively spotting, drilling and tapping the 5 holes take 2-1/2 minutes start to finish. Thousands of holes done on the same tooling.

So the how...

Use sharp tools. Regular quality HSS tools work well, cobolt is better, carbide if setup and work is rigid.

There are formulas to get the drill to spin at the correct rpm and how fast drill should progress with each revolution, but a seat of your pants method is to listen to what the "chip" tells you.

If you are drilling SS, you must be getting a chip, if not, the drill is rubbing.

**Warning**
More info then you asked for- - but some insight to the why.
Rubbing creates alot of heat. Heat makes the SS harder, creating more heat. Drill bits can drill holes becasue they are harder then the materail being cut. Drills start out soft and are hardened by a heat treating process...if a drill gets too hot the heat treatment is lost and drill turns soft again.

So you must be getting a chip when drilling. Now look at the chip, if it is coming out shiny silver your good, keep going. If the chip is looking tan its getting too hot which means turn the drill slower. If the chip is coming out Blue...your WAY Too hot, much slower and a drill that goes blue has usually turned soft. Stay away from that speed.

SS needs to be pushed on to cut...it goes back to you must be getting a chip. Drilling anything over 3/8 to 1/2" by hand is a real chore with a hand drill as you have to push SOO hard to avoid rubbing it can hurt. (its why drilling in a drill press is better, usualy slower speeds and the mechanical advantage of a drill press is up there. ANYWAY- Speed of most hand drills do not go slow enough...even my larger 1/2" drill have to bumped on and off to go slow enough. But it works.
Pre-drill. Nice idea, but there is a down side. The sides of the hole tend to be hard from drilling the smaller hole...but to go large sometomes you have little choice.
Cutting oil- - yes it works. But the oil also makes it difficult to read the chips as the oil burns off coloring the chips.


SS railing as in your Bimini top rail- - They are a royal pain. Thin SS is a bear to drill as the heat from drilling top side overheats the bottom as heat has no place to go. You have to really push with drill turning very slow...then as drill breaks through it wants to grab breaking the sharp edges, so your next hole, it may be time for a new drill bit. That is just the nature of "thin" SS. SS Tube is made from thin strips and formed round...the forming also cold works the material making it harder. Then you have the seam that gets welded and they can be hard, soft or a combination...drilling that is a treat.

I am assuming a hand drill on the boat to drill
So how...first center punch rail where you want the hole. Punch needs to make a dimple. Use a drill small enough to locate in the dimple, if not the drill just dances around. I prefer not to predrill so I may stop before breaking through...then use the right tap drill size to go through. A small countersink to chamfer slightly larger then your screw diameter comes next. Countersink angle also helps to get the tap started.

Tapping-- Sharp tap, make sure you start straight. Taps are very hard and do not bend so use a tap handle with even pressure on both sides turning and pushing straight in. If tap jams, do not force, but back off a little to break the chips and clear the flutes. Then proceed again till though. If it should bind still after backing off a little, remove tap, clear chips on tap flutes and in the hole. Tapping fluid is a benefit...SS can be hard, but it is also gummy and the fluid lubricates the tap so chips slide instead of sticking to the tap.



If your thinking of saying to use SS over aluminum...its overkill. The bolts will shear before they pull out of either material.





Mike is right about fine thread having a larger solid crosssection after bolts are threaded. If I had to mount to a plate and I was the least bit concerned about bolt strengh, I'd go up a bolt size or two over using a fine thread in an aluminum plate, especially in a salt water boating environment.



I gave my opinion early on about the glassing in wood and lag bolted being good. My original wood H cleat mount is 58 years old and just snapped a 1/2" dock line. Or opting for super simple and strong through bolting the cleat to hull.

Personally I have reservations about encapsulating alum in fiberglass with an exposed section. Alum and saltwater= corrosion.


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Re: Requirement of backer board for stern cleats?

Post by bob lico »

thank you tony we are on the same plane. i decided to make cleats strong enough to put individual straps on each cleat and literally pick up the boats buy rear cleats directly below hawsepipe. step one i cut out a piece of aircraft quality titanium 1/2" thick and 10" wide and two foot in height. a real pain in the ass to drill and thread using cleat as template and drill and tap 1/2" NF . i spend a week laying up the plate to the ground to green glass transom . i slayed up 2 1/2 " of bias at 45 degrees to each other and 10 layers of woven roven.next step i made a 1/2" panel of Azek brand PVC board across the entire transom with back up flush with back of Azek panel (it looks like the cleat is being supported by the 1/2" Azek, creates a good laugh) . trust me you could lift the boat by the transom with a crane if you wanted too. i don't want to mislead anybody titaniam is a bitch to work with.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Bob, I'd ask why...but your Bob.
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Re: Requirement of backer board for stern cleats?

Post by bob lico »

carl i have a towing attachment on my 100 ton USCG lic. i throught i might have to tow a container ship into new york harbor some day.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

so there is a spectrum of strengths.....

Original B25 - Molded fiberglass stern panel held in by a bunch of screws, cleat thru-bolted - pretty strong but towing with a non-stretchable tow rope allowed me to pull out the screws on the bottom and pop open my engine cover.

Original B31 - wooden pieces held in by fiberglass work - most likely woven roving and polyester resin - plenty strong - handles stresses of much larger boat for many years - well proven.

My plan for bonding in an aluminum plate and putting several layers of fiberglass set in vinylester resin - plenty strong for a smaller vessel than a B31.

something stronger than my plan, epoxy resin, more glass, etc

even something stronger - not sure what

even something stronger than that

Bob Lico's setup

My requirements is a bit better than the original B25 setup, to be able to work in vinylester to eventually have a clean gelcoated surface, I think my plans will achieve that. Will it be the best? heck no, but I do not have the same requirements as Bob nor anywhere near it. Something tells me Bob's setup the whole hull would fall apart before his cleats would come out.
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Re: Requirement of backer board for stern cleats?

Post by mike ohlstein »

ktm_2000 wrote:Original B31 - wooden pieces held in by fiberglass work - most likely woven roving and polyester resin - plenty strong - handles stresses of much larger boat for many years - well proven.

My plan for bonding in an aluminum plate and putting several layers of fiberglass set in vinylester resin - plenty strong for a smaller vessel than a B31.

something stronger than my plan, epoxy resin, more glass, etc
Ok, one more time. Epoxy isn't stronger than polyester. Epoxy is an adhesive while polyester isn't. Polyester feels sticky. I get it...... It's still not an adhesive. When they originally built the boats and glassed in the wood that the cleats are screwed into, they used polyester resin. That's ok, as long as they are primary (or chemical) bonds. That doesn't happen 45 years later. 45 hours, yes. 45 years, no.

Also, while more glass is often stronger, it's the layup schedule that makes the biggest difference.
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Re: Requirement of backer board for stern cleats?

Post by mike ohlstein »

Perhaps reading this particular article from Captain Pat will help. Here he builds a large repair section from polyester, and then epoxies it into place....

http://bertram31.com/proj/tips/hull_repair/index.html


"Now, why didn't I just lay up the hull directly?

I could have, of course, but:

1. It's far easier, cleaner, and more controllable to lay up on a shop table than on a semi-vertical hull.

2. I want the bulk of the patch to be polyester/glass to conserve on the expense of epoxy.

3. New polyester only has a mechanical bond on old polyester. Epoxy, being a true adhesive, will bond the panel to the old glass far better than any bond could be achieved using polyester.

So my plan of attack is to create a strong, void & bubble free polyester panel, that will be bedded with thickened epoxy, and then tabbed around the perimeter with epoxy & fiberglass. The resulting repair will be very high strength, exceeding the strength of the original hull, even in a non-damaged area, by choice of materials. The cross section of the repair will closely match the hull thickness in similar, but un-repaired areas. Finally, the repair will be more economical than epoxy glassing directly to the hull & with less shrinkage to potentially print through over the coming years"
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Re: Requirement of backer board for stern cleats?

Post by Tony Meola »

Carl

Thank you. Actually very informative.
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Well, if you want to keep the drilling and tapping simple and worry free, you could always hand your plates and cleats to a machine shop and if worried about dissimilar metals contact, have them
Heli-Coil your plates (stnls). This is what Volvo Penta did from factory on there drives, at least the 280 drive I owned was wherever there was a stnls fastener into aluminum. I couldn't imagine a competent machine shop taking too much time in doing this. In knowing how Bertram put original cleats on wooden blocks with lag screws, your plates will exceed original strength and look nice doing it. I tore mine right off (blocks)with a short bar- the roving just pulled right off hull.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Rocky wrote: Heli-Coil your plates (stnls). This is what Volvo Penta did f
You have your answer right there, over-complicating simple to the extreme with little to no benefit, a feat Volvo is well known for in the marine world.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

bob lico wrote:carl i have a towing attachment on my 100 ton USCG lic. i throught i might have to tow a container ship into new york harbor some day.


AWESOME answer Bob!
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Yeah Carl, why my original suggestion of teff-gel.
I like to think we all have some “well thought out in us”, sprinked with some overkill in there too! Bob for instance, now that’s extreme!
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Re: Requirement of backer board for stern cleats?

Post by Tony Meola »

Actually this was an informative discussion. If I get ambitious enough, I may glass an aluminum plate to the back of the block and tap it so I can use as bolt instead of what is thered now.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

It's easy to get caught up in Rube Goldberg contraptions. And while fun to watch it's concerning that each of the steps along the way further complicate and introduce points of failure.

Glassing in a mounting plate is pretty straight forward, just remember those countersinks in the cleats are there for a couple reasons. Flathead mount flush and the head provides location and support preventing the cleat from sliding sideways adding to the shearing action. It was mentioned fine thread has a larger crosssection then a course thread...and that makes a fine threaded bolt stronger....while true the point forgottten is the bolts used should not be fully threaded to the head for just that reason. Or you go up a size.

Who knew there could be so much talk about mounting cleats...
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Re: Requirement of backer board for stern cleats?

Post by Tony Meola »

Carl

It is like that book from the 70's that was titled. "Everything you wanted to know about sex but were afraid to ask".

We all wanted to know how to remount but were always afraid to ask.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Tony Meola wrote:Carl

It is like that book from the 70's that was titled. "Everything you wanted to know about sex but were afraid to ask".

We all wanted to know how to remount but were always afraid to ask.


lol
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

let me get Mike riled up............

I agree with you that Epoxy is stronger than polyester and vinylester resin but I think vinlyester will be "good enough" for my application. Going back to physics class, Force = Mass x Acceleration my B25 is less than 50% of the weight of a B31 so any action I put on my boat pulling on a cleat, I would have to do more than 2x the acceleration to generate the same amount of force as a what a B31 would need to do. What that means to me is that I can get away with not building that area up to the same level that a B31 owner would need to do. I think my plan will be more than acceptable for a B25 but would be unacceptable for a B31.
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Re: Requirement of backer board for stern cleats?

Post by Carl »

Ut oh...it's back to physics class.


I'm not sure what class this came from... but Size Matters. A 31''s cleats are larger than a 25's so there is more surface are being glued in place on a 31 making for a proportionally stronger bond.

I am really just assuming the cleats are larger on the 31, I have not seen a 25 to know.


At the end of the day, it's your boat and you get to do what you want. It just seems odd to go through all the extra work to make the backing plate as strong as possible (although not Bob strong) then glue it in place with a lesser glue. Kinda like going with oversized Brembro brakes and leaving the old undersized wheel studs. Or buying Internationals and using crappy line. Buying and oversized anchor with lots of chain, but undersize anchor line, Or...
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Re: Requirement of backer board for stern cleats?

Post by mike ohlstein »

I majored in physics (for 2 years) and owned a fiberglass shop for several years. Don't make me find you......
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Re: Requirement of backer board for stern cleats?

Post by Tony Meola »

Ok, so this is a first. I have seen a lot of threats from Mean Mike, but this is the first time I can remember that he has used the "Don't make me find you" card.
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Re: Requirement of backer board for stern cleats?

Post by Snipe »

Trying to post some pictures let’s see if it works https://imgur.com/gallery/9sX5kdt
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

Snipe - those aren't going anywhere without an extreme amount of force.

Not that I would go down that path as I like the triangle hawse pipes that my boat came with in the top cap were you attached your cleats, I am curious how you added chaffe protection when passing the dock line through the side of the hull?
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Re: Requirement of backer board for stern cleats?

Post by Snipe »

I have some oval hawse pipes that I am installing. I did away with the triangular ones so I can install covering boards at some point with a clean look.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

I didn't want to mess up where I needed it for real so I did a test hole and tapped it in the corner of one of the plates, the area can be filled in when I bond the plate, it came out ok but I don't think it is completely right. The tap was getting hard to turn by hand and I didn't want to snap the tap so I backed it out, cleaned the waste material, covered it with more oil then put it back in. A screw goes in fine but it is somewhat sloppy, I was fairly careful to not cross thread while being gentle putting the tap back in but am sure I caused the slop by not getting it done in one pass. I will research some more before trying another test hole.
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

I'm sure a lot of you know this metal tapping tip, I am not as familiar with metalworking, this is what I learned last night. I watched a couple of youtube videos then did another test hole which seems to have turned out well. After turning the tap in a few turns forward and getting to the point of getting jammed up, turn it backwards a turn or so to break up the waste material then go back forward and cut some more, rinse and repeat until you are done. I think my mistake on the first test hole was taking the tap completely out of the hole to clean it and when I put the tap back in, it was ever so slightly cross-threaded. By keeping the tap in the same thread pattern there is less of a chance of cross-threading and the screw fit is tight.
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Re: Requirement of backer board for stern cleats?

Post by Rocky »

Yes practice makes perfect, good your doing that off to the side before the real holes. And don't forget that epoxy lesson, or else!
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Re: Requirement of backer board for stern cleats?

Post by ktm_2000 »

plates drilled out, tapped,, junk screws with their heads cut off waxed into the holes. I cut 1/4" deep crosshatch patterns in the back of the panels with a grinder blade to add more surface area to bond. I mixed up a 16oz batch of Epoxy for each plate then mixed with milled fibers and cabosil. I could have probably done it in 1 batch but the fillet around the edge took up a lot of material but it also adds a lot of surface area and will make it easier to cover in 1708.
https://photos.app.goo.gl/86UcGGpPCG8TRAUT8

I don't have enough epoxy left to do 3 layers of 1708 the size I was hoping to (2'x3') so I may only do smaller pieces of glass covering the plates or do the covering glass in vinlyester. I have no other tasks for epoxy this year and I don't want it to sit so I'm not buying any more right now.
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Re: Requirement of backer board for stern cleats?

Post by mike ohlstein »

Image
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