2005 170 Montauk Bow Rail Welds Breaking

[DonnaMarie]

For the past two seasons, both sides of the bow rail (10:00, 1:00 and 2:00) [on a 2005 Boston Whaler MONTAUK 17 boat] needed to be re-welded [because] they split from their mounts. It's a very expensive task. Has this happened to anyone else? What can be done to help eliminate [the breaking of the welds]?

Seems like there's a flaw in how this bow rail was designed as [the welds have broken] three times. My boat is only used on the weekends in summer months, in river and bay. I wanted to drop the rail, but [to drop the rail would be] cost prohibitive for me right now.

[Give] suggestions on what to do to eliminate [the breaking of the welds of the bow rail of the 170 MONTAUK at their mounts].

Does Whaler cover this under their warranty program?

Appreciate your thoughts on this. Thanks, Donna

[jimh]

To discover if the welds on the bow rail of a 2005 170 MONTAUK are components that are covered under the manufacturer's warranty against defect in original manufacture, I recommend you read the warranty statement that came from Boston Whaler. Or, contact Boston Whaler customer service via telephone and discuss the warranty coverage with them. Or, contact the Boston Whaler dealer.

Since the warranty coverage was for a 10-year period, and a boat sold as a model year 2005 boat could have been sold as early as the summer of 2004, it seems to me on the basis of elapsed time to 2017 that the period of the ten year warranty coverage may have already expired, since perhaps as much as 13 years have elapsed.

[Jefecinco]

How the bow rail has been used can affect the life of the welds. The purpose of the rail is to keep people in the boat. I've seen the rail used for play with adults and children hanging from it and even using it as a launch when diving. I've also seen it used as a guide while docking and seen a few rails malformed from collisions. Welding repair of rail bases is not a simple repair as proper alignment when remounting the rail is critical. If the base is under considerable stress when remounted the weld is at risk for early failure.

I would look for a rail fabricator to repair the rail if the welds fail again. Alignment and quality welding are important and not every welder is experienced with welding stainless steel.

[jimh]

The weld of a bow railing to its mounting base would fail in two general circumstances:

--the weld was poorly done and failed due to a defect in the weld itself, or

--the weld was done properly but there was continual vibration of the railing and this working of the railing against the mounting base caused fatigue which eventually broke the weld.

Bow railings can become involved in vibration and movement if there is some exciting force acting to set them into motion. A typical source of the exciting force is the outboard engine and its propeller. I have seen on my own boat that some combinations of engine speed and propeller will cause vibrations to be created which can be transferred to the bow railing structure, causing it to vibrate. The engine speed, propeller pitch, and the number of blades on the propeller are influences on the frequency of the vibration. Changing any of those three will change the vibration energy.

[Wweez]

The 2005 170 bow rail I have is poorly designed. Looks nice but almost totally unsupported. I am surprised any survive. The span across the bow is much too long. The rail vibrates and flexes from waves--not just people leaning on it.

There was an option on some [Boston Whaler boat railings to have] an opening center front [rail]. I would like to have one of those.

[mwallac1]

I tie a line between rail and bow navigation lamp chock to minimize vibration at low speeds.

[jimh]

If a segment of a structure like a bow railing has a tendency to vibrate when excited by certain outside forces of certain frequencies, the vibration can be reduced or suppressed by use of dampening material. For example, as mentioned above, one user of the 170 MONTAUK reports that he ties a line between the mid-point of the long center segment of the bow railing and a bow cleat or chock below it. This coupling of the vibrating element to a fixed structure helps to suppress the vibration.

In the case of a boat bow railing, the dampening material could be concealed inside the tube of the railing. An effective dampening material is some material with some weight that can be coupled to the vibrating element at a point of attachment that will suppress the initial movement of the vibration. It may be possible to similarly suppress vibrations in the railing by inserting some material into the tubing. My first idea is to insert some sort of heavy rope material into the tubing. This may not be possible with the railing in its original condition, as there may not be access to the interior of the rail tubes. But, if the railing has broken free of its welds, it might be possible to insert some heavy rope into the interior of the rail tube; whether or not this would have the desired effect would have to be discovered in the field by experimentation.

Another option to reduce vibration at one segment of the rail is to add an additional vertical support tube. Since the railing is being re-welded in the repair, it would be possible to fabricate an additional vertical support tube that would be welded to the original rail and fastened to a base near the center of the segment that is vibrating.

The total mass of the vibrating segment could also be changed by attachment of some external weights. The weight could be formed into a second rail segment which could be attached mechanically to the original railing and left to hang below it. The point of attachment could be made in multiple locations, and the system tuned to suppress the offending vibration. See the article on Stockbridge Dampers for some ideas.

Link: https://en.wikipedia.org/wiki/Stockbridge_damper

Also, the mass of the vibrating element could be altered by adding other material inside the tube. For example, perhaps filling the tube with some sort of quick-setting liquid resin would have an effect. Again, experimentation would be needed to see if this was effective.

As mentioned already, the vibration is created by some external exciting force. Another approach to reducing the vibration is to change the frequency of the external vibration force. The simplest method in the case of an outboard engine is to change the number of propeller blades. If a three-blade propeller is in use and there is a vibration problem, try changing to a four-blade propeller; or vice-versa.

[Jefecinco]

I suspect the vibration is caused by the engine's tendency to vibrate at idle speed. Even my in-line four cylinder Verado has a noticeable vibration at idle. My 190 Montauk was purchased without a bow rail so I lack first hand experience with the problem.

If the vibration is a problem only at idle speed a solution is to minimize operating the engine at idle. This can be accomplished by increasing the idle speed, shutting off the engine rather than allowing it to idle when the engine is not needed, or bumping the throttle just enough to avoid the vibration when that won't interfere with safe operation. I believe most boats spend more time at idle speed than at any other speed.

[Wweez]

The weakness is caused by no support across the entire front of the boat, unless you got the split front one.

Some [person] in a dark room designed it and some [person] higher-paid approved and built it. The rail might keep you in if you fell against it, and that is the reason mine is still in place, but if you held on and went over you would re-sculpture the thing.

It's real pretty, though.

[Antonioimp]

I had the same problem on my 2004 Montauk I was able to get a permanent fix with a JB compound that I bought at Homedepot.

[sea_of_hands]

I just repaired a broken rail weld on my 2002 Montauk with a 60 degree 7/8" Stainless Steel Rail Fitting I picked up at West Marine. The screw holes were identical to the broken off Whaler base piece that broke off. It was a clean break and an easy fix. I wish I would of tried this years ago. I went too long long holding it in place with gaffers tape and bungee cords.