Help Sealing Under Waterline Through Bolts for New Rudder Port

[Tom J]

One other thing, these bolts are made to use with a washer. If we used them how would we countersink them with a washer? I did try to research that because we actually prefer using them because they are larger but I couldn't find how to countersink with a washer.

If you are using the washers, you still need to have a beveled countersink under the washer. This forms a plug of sealant that stays tight against the bolt. You mentioned that Caliber had recessed the bolts. Is this the type of recess you meant, or a flat recess?
Also, as mentioned, you must tighten the nuts on the inside, and hold the bolt so that it doesn't turn once it is inserted through the hole.

 

[SV/Journey]

If you are using the washers, you still need to have a beveled countersink under the washer. This forms a plug of sealant that stays tight against the bolt. You mentioned that Caliber had recessed the bolts. Is this the type of recess you meant, or a flat recess?
Also, as mentioned, you must tighten the nuts on the inside, and hold the bolt so that it doesn't turn once it is inserted through the hole.

No Caliber did not use a washer, this is something we changed but I think we will go back to the other type of bolt that does not need a washer.
Thank you for your excellent info! Very helpful!

 

[dLj]

I would use the size needed from this group:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Or these:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Unless they are metric, then:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

I'm not sure it matters if they are shoulder bolts or fully threaded, although if I could get the right size in a flat head shoulder bolt, I'd prefer them. But if your holes are properly sized, and you are filling the hole with sealer as has been described, then both should work.

If you need to resize your hole then using an epoxy with filler might be called for, but not being there, it's really hard to know what is best.

dj

 

[SV/Journey]

Your original installation with the bolts and washers may not be the very best in theory best but it should work well. My only question is: WHY THE HELL SO STINGY WITH THE SEALANT ? I use more sealant when dealing with above water installations. You want sealant gushing out of every piece of hardwear on the OUTSIDE of the hull as per @FastOlson but not on the inside. This must be clean. Wipe it off when you're finished.


View attachment 191982

Tighten nuts FROM THE INSIDE ONLY. Do not tighten the bolt heads from the outside under any circumstances. NONE ! ! ! ! !

Last question, are the bolts snug in the holes ? Snug but not sloppy.

There is no reason whatsoever for your arrangement to leak if you:

- use plenty of sealant
- tighten from the inside ONLY
- ensure the bolts are a snug fit.

EDIT: coat the smooth shaft of the bolt with LOTS of sealant as it slides into the hole through the glass. This further ensures another seal to rely upon.

Thank you for your reply. We certainly didn't intend to be so stingy with the sealant. We just underestimated how much to use and did not know about not turning the bolts which caused what we did use to basically squeeze out. We also got some bad information and thought we only had 15 minutes working time with 4200 FC which really made us feel rushed. We will do it much different this time! Thx again

 

[Ralph Johnstone]

We also got some bad information and thought we only had 15 minutes working time with 4200 FC

More like several hours if the conditions are not extremely hot and humid.

Let the above incident be a lesson to you. The absolute worst source of information out there is "some guy on the dock". Online sites are a little better although you don't know who's knowledgeable and who's otherwise. Use Google to find manufacturer's web sites and use their publications in situations like working time for 3M 4200. They know best, they made the product.

 

[dLj]

Here's my long winded question: we've searched everywhere for diagrams or info on how to best apply sealant to under waterline thru bolts with washers. There's very little detailed information and a lot of conflicting information. We really don't want to do this again! We've read Maine Sails suggestions against creating a gasket by not tightening down all the way, waiting for the 4200 to set then tighten the nut but to us this sounds like the best way to do it.

No one has really addressed this portion of the initial enquiry.

Here's my 2 cents: If you found useful information on @Maine Sail 's site use it. My observations over the years is he has really good, hands-on, practical advice, you won't go wrong following what he suggests.

There may be others ways to do things also, but his advice is about as good as you'll find anywhere.

dj

 

[Ralph Johnstone]

My observations over the years is he has really good, hands-on, practical advice, you won't go wrong following what he suggests.

Very true, however my first choice is always to search out the manufacturer's instructions when dealing with such things as 3M 4200.

As for how much 4200 to apply .................. that I don't know ? You're either born with that knowledge or hire someone to do the job for you.

 

[dLj]

Very true, however my first choice is always to search out the manufacturer's instructions when dealing with such things as 3M 4200.

As for how much 4200 to apply .................. that I don't know ? You're either born with that knowledge or hire someone to do the job for you.

I'd recommend you actually read Maine Sails instructions.

dj

 

[Ralph Johnstone]

I'd recommend you actually read Maine Sails instructions.

I read it last year and checked it again just now. What did I miss ? ? ?

@SV/Journey said one of his biggest problems was that someone told him that 3M 4200 only had a 15 minute working time.

We also got some bad information and thought we only had 15 minutes working time with 4200 FC

He felt he had to rush and as a result, short changed the amount of sealant. Main Sail doesn't use 4200 ......... doesn't like its properties. Doesn't use it on thru hulls. Didn't mention the working time of Sikaflex 291. So what's the working time for 4200 ? Didn't help @SV/Journey much. Now he's got the manufacturer's specs on 4200 and he's getting the job done under difficult conditions.

Main Sail doesn't really dwell on keeping the bolts from turning as you tighten the nuts, in his write up.

And after all, these were the correct flat head bolts for the job. Little bit of turning isn't going to hurt too much here. Unfortunately, not much help to @SV/Journey here either.

So quit your bloody nitpicking and take a practical view of what he's trying to do, with what he's got, in a less than ideal location.

PS: @SV/Journey , just pay my air fair plus food & a place to sleep and I'll be glad to come down and do the rudder port job for you free . Plus any other little jobs as well. Winters here on the Wet Coast are really cold and miserable .

 

[LloydB]

The question came to mind how could you check to see if still leaking after 3rd try before splashing again or in the first place for that matter?

 

[Ralph Johnstone]

The question came to mind how could you check to see if still leaking after 3rd try before splashing again or in the first place for that matter?

Nothing short of the acid test of splashing the boat.

Maybe get inventive and put ink on the inside around all fittings and then fit a vacuum cleaner to the outside of the hull on the fittings (screw or bolt heads) and see if anything sucks through. Really more annoyance than anything else if a leak doesn't show and yet it leaks in the water. I doubt that these were large leaks, just the annoying dripping you sometimes get.

 

[SV/Journey]

You

The question came to mind how could you check to see if still leaking after 3rd try before splashing again or in the first place for that matter?
[/QUOTE
You have no idea how badly we wish there was a way to test for leaks before splashinh! These have been the most expensive mistakes of our lives not to mention extremely frustrating! I'm certain we can't be the only ones this has happened to. I wouldn't wish this on anyone!

 

[Ralph Johnstone]

I wouldn't wish this on anyone!

Except for maybe the guy who said " 3M 4200 FC only has a working life of 15 minutes" .