Ideas, Thoughts, Recommendations, I'll Take Anything

[Ralph Johnstone]

My forward opening hatch is a Bomar 1080-10A with a single support arm. Manufactured in 1998 and installed in my 1998 H-310, it has a single support arm.

Since day one, this hatch has been near impossible to open due to the friction in the holding mechanism of the support arm.

Below is an exploded view of the holding mechanism :

This is a closeup of the above exploded view.

Once the lid has been easily and smoothly pushed open, it takes only a small amount of torque in the CW direction to hold the lid in place. When it comes time to lower and lock the lid closed, that's when the grunting and cursing commences. The amount of CCW torque needed on the grooved handle to relieve the pressure on the lower tapered split tube is many times the initial CW torque applied. Should someone unfamiliar with the problem open the hatch and secure it too tightly, a wet rag and pump pliers are required to loosen the upper grooved tube.

Anyone ever run into this and how, or did you overcome it ?

Any and all replies : serious, humorous, comforting, discomforting, insulting and extremely offensive would be most appreciated.

 

[JamesG161]

Bomar 1080-10A

Mine is Bomar 1011-10 with 2 openers.

I guess , just like your accumulator, short changed again.

Jim...

 

[Joe]

Ralph, I wish I had constructive insight regarding the hatch issue. However, I will congratulate you for perhaps the best "I have a problem" presentation I've seen here in quite some time. Such an achievement in communication, where the challenge has been made so clear, is bound to stimulate a creative, yet precise, solution. Here's wishing for a successful outcome.

 

[Rick486]

My forward opening hatch is a Bomar 1080-10A with a single support arm. Manufactured in 1998 and installed in my 1998 H-310, it has a single support arm.

View attachment 217491

Since day one, this hatch has been near impossible to open due to the friction in the holding mechanism of the support arm.

View attachment 217496


Below is an exploded view of the holding mechanism :

View attachment 217499


This is a closeup of the above exploded view.

View attachment 217500

Once the lid has been easily and smoothly pushed open, it takes only a small amount of torque in the CW direction to hold the lid in place. When it comes time to lower and lock the lid closed, that's when the grunting and cursing commences. The amount of CCW torque needed on the grooved handle to relieve the pressure on the lower tapered split tube is many times the initial CW torque applied. Should someone unfamiliar with the problem open the hatch and secure it too tightly, a wet rag and pump pliers are required to loosen the upper grooved tube.

Anyone ever run into this and how, or did you overcome it ?

Any and all replies : serious, humorous, comforting, discomforting, insulting and extremely offensive would be most appreciated.

I suspect your problem may be related to the increase in temperature of the mechanism due to sunlight. It could be heating the threaded segment of the locking mechanism, and/or the aluminum shaft.
You might try tightening the shaft mechanism with the hatch closed on a sunny day and see if there is a difference.
As a possible repair, consider shortening the threaded section of the locking mechanism to reduce the holding strength of the mechanism.

 

[Davidasailor26]

Maybe some PTFE or silicone lubricant on the threads to keep it from binding up so much?

 

[dlochner]

A few thoughts.

The weight of the hatch when open may be increasing the friction on the plastic parts making them more difficult to turn.

Plastic on plastic may have a higher coefficient of friction than we expect which when coupled wear on the threads increases the friction.

Lubricate the threads with Superlube. The same stuff Peggy wants you to squirt into the pump on your head.

 

[jssailem]

Great write up.
Lubrication seems like a quick fix.

I wonder if it will affect the function of the strut. Once applied will the unit still function to stop the hatch from closing.

Looking at the structure I think the difference in the force your wrist applies rotating the strut break could be a factor. You exert more force on the part in the CW direction than in the CCW direction.

Have you thought about replacing the adjustable with a spring loaded gas strut?

I used a pair of old design struts that worked on my old bow hatch similar to these.

Perhaps more cumbersome but finger tight they work.

 

[Tally Ho]

Great write up.
Lubrication seems like a quick fix.

I wonder if it will affect the function of the strut. Once applied will the unit still function to stop the hatch from closing.

Looking at the structure I think the difference in the force your wrist applies rotating the strut break could be a factor. You exert more force on the part in the CW direction than in the CCW direction.

Have you thought about replacing the adjustable with a spring loaded gas strut?

I used a pair of old design struts that worked on my old bow hatch similar to these.
View attachment 217508
Perhaps more cumbersome but finger tight they work.

I think you want to put some PTFE on the threads of the black plastic locking mechanism, not the strut metal arm.

And if you take some pressure off the hatch (manually push up on it) while turning the black plastic part CCW, is it any easier?

Greg

 

[Rich Stidger]

@Ralph Johnstone , I have the same problem with several of my hatches. I will be watching your thread for a solution. It appears that the binding is on the threads in the barrel vs the sliding friction on the strut, although after loosening my barrel lock, it is sometimes hard to get the hatch to close. This is a secondary issue, not your primary one.
Regarding lubrication, I would choose McLube spray as opposed to Superlube.

 

[Ralph Johnstone]

Thanks all for your replies although I see that none of them rose to the level of extremely offensive. Ho hum .

I agree with all that lubrication is at the heart of the matter, but don't ask me how. So far, I have tried the following lubes on the male threads and the lower split tapered portion of the bottom tube only.

-SuperLube
-plumber's teflon paste
-a mixture of plumber's paste and Superlube to thin out the mix

I have never touched lube to the aluminum rod as that's really going to cause problems with "getting it up and keeping it up ". In every #$^%&@* case, the feel of loosening the grooved tube has been identical on the first try after application of the lube. You bust a gut to break the initial binding force and then the rotation is as smooth as silk with the required torque gradually decreasing. It's as if the lube has never come into contact with the high friction area. So where the hell IS the high friction area ? ? ? Also I would mention that gently tightening the grooved tube is also as smooth as silk. No binding at all, but stop at that point and try to loosen by going CCW and it's jammed again.

My next move will be to scrupulously clean the two suspected high friction areas of old lube and try a dry silicone lube, McLube, and anything else in the workshop which is unlikely to attack the threads. At this time the threads appear to be in good shape.

I suspect your problem may be related to the increase in temperature of the mechanism due to sunlight. It could be heating the threaded segment of the locking mechanism, and/or the aluminum shaft.

Great minds etc, etc. .............. One of my early thoughts about 2001 while lying on my back early one summer morning in a sun drenched anchorage adn contemplating this thing. Some time, later in the fall with no sun and light rain, ran a few tests tightening and un-tightening the tube after a period and no difference to the crap I had already experienced.

I used a pair of old design struts that worked on my old bow hatch similar to these.

Perhaps more cumbersome but finger tight they work.

I can remember these in my grandmother's house over half a century ago. They would certainly work in this case. My only concern would be getting stuck in the eye by the rod while getting up in the middle of the night to see a man about a horse.

 

[Tedd]

That's a very shallow cone angle on the taper. As you probably know, the shallower the cone angle the greater the grip. Your strut has a taper shallower than a ball joint which, if you've ever removed one, can exhibit impressive grip. Since lubrication doesn't seem to work, I'd be tempted to try cutting more slots in the taper to help it release more easily. It's essentially a collet, so the more relief slots it has the easier it will grip and release.

 

[Ralph Johnstone]

I'd be tempted to try cutting more slots in the taper to help it release more easily. It's essentially a collet, so the more relief slots it has the easier it will grip and release.

Definitely worth looking into as an additional two opposed slots would definitely be able to close on the rod easier. However, not entirely convinced they would be inclined to offer a smaller resistance force when opening. If I can find a replacement aluminum rod and locking mechanism assembly, I will try this after experimenting with a few new lubricants. If I screw up the holding assembly I may be stuck holding the hatch cover open with duct tape stuck between the hatch cover and the mast. That would NOT be a class act.

 

[Tedd]

My thinking regarding the slots is two-fold.

Most importantly, extra slots will mean that the fingers of the collet will be pushing back against the nut with less force, which will reduce the torque required to overcome static friction and loosen the nut. I expect the material is very soft (relative to, say, tool steel), which means that the static friction will be non-linear with clamping force. Even a small reduction in clamping force could result in a large reduction in the torque required to overcome static friction.

In addition, the extra slots will reduce the torque required to lock the collet in the first place, which will further reduce the releasing torque.

That's all theory, of course. You'll only know if you try it.

 

[Ralph Johnstone]

You'll only know if you try it.

It all sounds good in theory. However, if I bugger up the taper on the lower tubing section, I'll be madder than a bull chewin' on a hornet. I'm searching for replacement supports now.

 

[JamesG161]

How about extra torque?



Jim...

 

[Ralph Johnstone]

How about extra torque?

And where does it all end ? Rubber strap wrenches with 36" snipes on the end ?

 

[jssailem]

I will try this after experimenting with a few new lubricants.

I suggest a Canadian product made by Lear Chemical Research Corporation called Corrosion Block. It is designed for metal. Since you’re going to experiment it might be worth a try.

Corrosion Block’s non-toxic, non-greasy atmospheric barrier protects metal surfaces for up to 18 months. It can be sprayed, brushed, or wiped onto marine electronics, batteries, circuit panels, standing rigging, fishing gear, inboard and outboards, and is compatible with plastics or rubber component found on your boat. Being “Pro Active” about corrosion control is the best way to protect your marine investments.​

 

[Claude L.-Auger]

I unfortunately do not have the number of my Bomar hatch, but my boat being an 84 it's certainly an older model. 20'' X 20'', it has 2 screwed on and off locks and only one holding arm. It is a very simple design with a notched sliding rod inside of a tube. To open the hatch, you release the 2 locks and push the hatch up to the desired opening, then screw the small handle into whichever notch of the rod you want. Has worked like a charm for the 24 years that I've owned the boat. Perhaps something like that would be easier to find than a solution to your problem ? Good luck

 

[JamesG161]

Rubber strap wrenches with 36"

Actually there is a smaller one in that $8 kit, that fits 3/4th inch.

Leave that one strapped on and use it to hang a "Emergency LED" light on it.

You did know that is an "Escape Hatch" just in case you below and sinking?

Safety and Convenience combined

Jim...

 

[Ralph Johnstone]

then screw the small handle into whichever notch of the rod you want.

This was the epitome of simplicity .............

.................. with the screwed lock mechanism. WHY did they have to change it to a new and sleek design which just about kills you when you want to release the rod ?

Thanks for the idea but I'm afraid it belongs to a long ago and far better design.