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Author Topic:   Weld failure on 170 bow railing stanchion
bobeson posted 07-05-2005 07:39 PM ET (US)   Profile for bobeson   Send Email to bobeson  

This weekend I discovered that my 2003 Montauk 170's forward port-side bow railing stanchion had separated from its mounting flange. It looks like there was a weld failure, much to my surprise. There have been no unusual or significant impacts to this railing, as far as I am aware, and the railing is not bent at all. The stanchion still mates with the flange in the original position, so that the fractured weld facets meet perfectly, which provides some evidence that the failure was not the result of some sort of impact stress. I suspect that this failure resulted from the combination of a poor weld and bow rail vibration while underway, but I have no way of knowing this for certain.

Since this boat is over 2 years old now, the railing is no longer covered by the warranty, so I suppose I'm left to fix it myself. Can anybody offer advice on removing and repairing the railing? Although I have a mig welding outfit, I've only worked with mild carbon steels so far, and I'm pretty much a hack welder, so I think I'll take this to a pro. Are the bases secured to the gunnels with any adhesives? Is it as simple as removing the screws from the flanges? Should I use any sealants when replacing the screws?

Thanks for any advice you can offer.

Plotman posted 07-05-2005 08:40 PM ET (US)     Profile for Plotman  Send Email to Plotman     
I'd still call chuck benett at whaler and ask him to help. This is clearly d defect in materials/workmanship if it is as you describe, and a fairly major repair to have to take on on a fairly new $25,000 boat.
bsmotril posted 07-05-2005 09:54 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Whaler fixed broken weld problems on my conquest hardtop well after the warranty on that component had expired. I second the suggestion to contact whaler. It would also help your case to have the support and agreement of the selling dealer beforehand. BillS
Jerry Townsend posted 07-05-2005 10:29 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Several things could have happened - including fatigue or a bad weld. Repairing is not a big deal. I suggest TIG instead of MIG - better weld and better looking. If you were closer - you could just bring it over.

Take the boat to a welding shop and let them tack the stanchion and the mount (putting masking tape on the glass around the mount), then loosen/remove the rail as necessary to raise the mount away from the glass, provide some protection between the mount and the glass and put up a good solid weld. ------ Jerry/Idaho

Chuck Tribolet posted 07-06-2005 03:47 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Shake whaler's tree about it. You aren't the first.


Floodtide posted 06-19-2006 11:23 PM ET (US)     Profile for Floodtide  Send Email to Floodtide     
I have this exact same issue.

Did Boston Whaler fix your rail?

Chuck Tribolet posted 06-19-2006 11:50 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The dealer fixed a buddy of mine's. Dunno whether it was the
dealer or BW that paid.

When it failed again, he took the bow rail off and hung it on
the fence. He's a diver and WANT'S to fall off the bow.


whalerdude posted 06-26-2006 04:54 PM ET (US)     Profile for whalerdude  Send Email to whalerdude     
Just had it happen on my 2006 Montauk. (see recent post)
They are replacing it with an entire new railing.

Other items being replaced under warranty:

Backrest for Cooler seat-vinyl wore through where it rubs against rocket launchers.

Certification plate-was falling off-New plate ordered.

Moulding on center console was peeling off-glued back on.

whalerdude posted 06-26-2006 04:56 PM ET (US)     Profile for whalerdude  Send Email to whalerdude     
Why do you think the welds failed??

I did NOT abuse my railing.

I DO think they need to add a center support post!

Tom W Clark posted 06-26-2006 05:03 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The weld failure is caused by metal fatigue which is induced by the flexing of the forward portion of the bow rail. The rail needs a bow stanchion.

Jimm posted 06-26-2006 08:34 PM ET (US)     Profile for Jimm    
Hey Boston Whaler if you're reading this - what Tom Clark said - c'mon make some up and I'll buy one. You don't want people to think the 170 is a cheap boat do you? If anyone sees me going along at about 1500 rpm's they can see the railing shaking violently. HELP !!!!!!!
whalerdude posted 06-28-2006 03:45 PM ET (US)     Profile for whalerdude  Send Email to whalerdude     
My dealer said that there is a post where a member describes how to modify the rail to add a center support piece. Can you tell me where to find that post?
Casco Bay Outrage posted 06-28-2006 07:44 PM ET (US)     Profile for Casco Bay Outrage  Send Email to Casco Bay Outrage     
I think you are referring to

scroll down to the entry by imko. photo links also included.

GreatBayNH posted 06-28-2006 08:03 PM ET (US)     Profile for GreatBayNH  Send Email to GreatBayNH     
All this talk is making me question whether or not to pro-actively bring this up with my dealer. I have a new 2006 Montauk 170 however I don't notice any shaking of the bow railing (at any speed)and at present it seems quite sturdy, even without the added support of a center stanchion.
swist posted 06-28-2006 10:16 PM ET (US)     Profile for swist  Send Email to swist     
I wonder if this is a function of just certain configuration options or whatever... but the front section of my 2004 Montauk 170 bowrail doesn't vibrate at all, although I certainly wouldn't be tempted to put all my weight on that part of it.
whalerdude posted 06-28-2006 10:51 PM ET (US)     Profile for whalerdude  Send Email to whalerdude     
I love my boat but I noticed the vibrating bow rail the first time out and was immediately puzzled as to why there was no center post support at the bow.

I have had 2 classic montauks and they had the center post.

However, the classic montauks had the vertical posts screwed into the base brackets and the screws always came loose and the posts would rattle.

If they just used common sense and put that front vertical piece on we would be better than the old ones and eliminate a problem that is bound to reoccur on other whalers Montauk 170s

GreatBayNH posted 06-29-2006 04:59 AM ET (US)     Profile for GreatBayNH  Send Email to GreatBayNH     
I'll certainly be looking for vibration the next time I got out. Could you describe this vibration for me. Is it visible to the eye from the console and/or is it audible? Or does it require one to grab the rail while underway to detect/ feel the vibration?

Chuck Tribolet posted 06-29-2006 10:28 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The vibration is very visible from the console while underway.


Jerry Townsend posted 06-29-2006 06:29 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Guys/Gals - I offer the following only from my knowledge of vibration - bearing in mind that I do not have a Montauk.

The rail failure problem and vibration is a design defect - and as such, should be corrected by BW. I'm surprised that BW have not accepted that fact and acted on it.

The failure is caused by the vibration that many have commented on - and the resulting stress being excessive for the material and/or welds. The vibration problem is caused by the vibrating engine and the vibratatory motion of the boat - being too close (frequency-wise) to the natural frequency (the frequency that the rail wants to, by design, to vibrate at) of the rail.

The design of the railing should have, by definition, been based on the driving frequency of the engine and of the boat motion - both sources are known to the designer. The design of the railing should have, by definition, been based on the calculated (or tested) dynamic response of the railing. Had this been done, the problem would have been identified and the design corrected.

My intrepretation of the problem is that BW did not consider the dynamic loading of the railing in their design. As such, BW should accept their error of the defeciency and provide the fix.

Correcting the problem can be done by stiffening the rail/mount material and welds and stiffening the railing. This increases the natural frequency of the railing and decreases the magnitude of the motion - thereby decreasing the stress level. --- Jerry/Idaho

mikeyairtime posted 06-29-2006 09:11 PM ET (US)     Profile for mikeyairtime    
My 04 170 Montauk has zero vibration at any RPM. The stainless one piece bow rail seems very stout. No problems yet.
Marsh posted 06-29-2006 09:21 PM ET (US)     Profile for Marsh  Send Email to Marsh     
My 2004 Montauk 170 exhibits extreme bow rail vibration at certain engine rpms - especially at low rpms as seen while traversing "no wake" zones. I have found that I can minimize the vibration with slight throttle adjustments. However, the vibration is never eliminated, and I no-doubt will experience a weld failure at some point in the future, unless I do the modification done by Imko in a separate thread. The more pressing reason to do the mod, is that the bow rail, as configured from the manufacturer, does not appear to be able to withstand any sort of load at bow dead center. Adding another stanchion at this point would greatly improve the load capacity, and would also have the benefit of reducing or eliminating vibration.

It's a crappy design, and Whaler should be ashamed. But, hey: they saved $12 bucks or so in manufacturing costs on each 170 Montauk built since the design change. That all adds to earnings per share.


GreatBayNH posted 06-29-2006 09:53 PM ET (US)     Profile for GreatBayNH  Send Email to GreatBayNH     
How does one e-mail BW about this issue?
Jerry Townsend posted 06-30-2006 11:27 AM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Marsh - your connecting the engine rpm with the vibration is good information. There should be one (maybe two) engine rpms that more predominately causes the railing to vibrate.

But, BW also knows the typical range of engine rpms and the engines used with that boat. They then can calculate the vibration characteristics at those engine rpms. They can (or should) calculate the dynamic response of the railing and base, in part, the design the railing on that dynamic response.

Stiffening the railing can be done in several ways including: adding another stanchon as some have mentioned, welding small triangular gussets at selected joints. Or - fabricating a new stainless railing of properly designed and sized tubing with properly designed and built mounting. --- Jerry/Idaho

whalerdude posted 07-04-2006 12:23 AM ET (US)     Profile for whalerdude  Send Email to whalerdude     
Can you give me the link to imko's modification

Also, what is Whaler's modification to the railing this year. My dealer said that the Railing for my 2006 Montauk is not on the current production Montauks.

Marsh posted 07-04-2006 11:15 AM ET (US)     Profile for Marsh  Send Email to Marsh     

Check this thread, 3rd reply from the end.


Maximus posted 07-04-2006 02:32 PM ET (US)     Profile for Maximus  Send Email to Maximus     
Is the vibration and resulting weld failures attributed to a particular motor? Did gear ratios differ from '03 to '06?
GreatBayNH posted 07-05-2006 01:58 PM ET (US)     Profile for GreatBayNH  Send Email to GreatBayNH     
My 2006 Montauk 170 had its first fresh water experience this week. I paid close attention to the bow rail and noticed considerable vibration at headway speed. Other that that I didn't notice much vibration but I'm thinking a center stanchion might be better installed sooner rather than later. Now how do I go about getting BW/dealer to pick up the tab?

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