Structural Integrity of Owner-Added T-Top

[RaySmiley]

The previous owner of my 2003 170 MONTAUK added a custom-made T-Top. The T-Top and the center console both wobble [when the boat is underway] in a bit of chop, and [this occurs at a boat speed that] is not super-high.

Q1: can this wobble motion cause the [center] console to become loose?

Q2: is the [wobble motion of the console and T-Top] “safe”?

Q3: should I remove the T-Top?

Q4: should I replace the T-Top with a Bimini Top?

BACKSTORY
I recently purchased a 2003 170 MONTAUK. The previous owner barely used it. The 2003 170 MONTAUK was sitting in his yard [for ten years, or] since at least since 2016. The first time I was able to take out the boat was just a few days ago.

I have spent $20,000 on this boat, which includes installing a new Yamaha 90-HP engine and buying a new trailer. At this point, I am “in” too far to give up.

All suggestions [in reply to my questions] will be appreciated.

[jimh]

Q1: can this wobble motion cause the [center] console to become loose?

If the T-Top and center console are already wobbling, then they are already loose.

Q2: is the [wobble motion of the console and T-Top] “safe”?

The notion that there is already a wobble in the support structure for the T-Top and the console has become loose are evidence of problems in the design, reducing its safety.

Typically when Boston Whaler offers a hardtop or T-Top option for their boats, they have very carefully assessed the structure and the load imposed on the hull at the attachment points. The attachment points are then properly reinforced to sustain the load that will be exerted on them. Also the rigidity of the supporting frame that holds the hard top is carefully analyzed so that it has proper flexibility to match the flex in the hull, in order to reduce the loading on the attachment points.

With some "custom-designed" T-Top there is no way to know what sort of calculations were done to create a structure that would have appropriate flexibility. And, certainly, there is little expectation that the attachment points chosen have been sufficiently reinforced.

[jimh]

Q3: should I remove the T-Top?

Without knowing much about the construction of the T-Top and how it has been installed, for readers to form an opinion on whether to remove it will be difficult.

Q4: should I replace the T-Top with a Bimini Top?

A canvas top or Bimini Top is much more common on a 17-foot boat like a 170 MONTAUK. The advantages of a Bimini Top over a T-Top are:

• reduced weight aloft, leading to better stability;
• reduced windloading, leading to less drag;
• ability to fold and stow the Bimini when not needed, such as for trailering the boat at highway speeds;
• better protection from sun due to the Bimini Top usually being closer to the heads of the people standing under it compared to a T-Top; and
• much less effect on boat performance due to lower weight and lower drag when underway.

Unless you are a very avid angler and the particular species of fish you are targeting will require that you have 360-degree walk-around ability in the cockpit area in order to be able to successfully land the fish, I don't see a compelling need for the T-Top.

[NorthShoreWhaler]

It would be helpful to post some pictures of the boat and T top.

[RaySmiley]

Theres no cracks around the [T-Top frame] mounts in the [cockpit deck] around the T-Top or console.

By wobble I mean [the T-Top and center console] shimmy side-to-side.

[Moderator's note: the new non-boating topic about how to have image files hosted by the website and included in posts to the forum and several replies to the new topic have been deleted. Please do not use a boating forum to solicit advice on how to use the forum. For help with the forum software, post to the forum Introduction to the Forum Software.

There is already a topic in the Introduction to the Forum Software forum that discusses how to upload images files for hosting on the website. Read more at Adding Image to Post.]

[RaySmiley]

My boat is a 2003 170 MONTAUK with a T-Top. The T-Top is fastened into the [cockpit deck] about one to two-inches from console, and also fastened to the console.

The T-Top wobbles back-and-forth [when the apparent wind on the boat has a strength of about] 10-nautical-miles-per-hour. What appears to be a plastic part of the console wiggles a bit with it. The console itself is not "walking" but it is definitely under stress.

[NorthShoreWhaler]

[Download the PDF file linked below, which is a drawing from Boston Whaler that shows the locattion of embedded reinforcement areas in the hull of a 2002 170 MONTAUK:]

170-Montauk-Wood-Locating-Models-2002.pdf

(94.44 KiB) Downloaded 47 times

[You will see that there is] no [embedded] wood on either side of the center console for securing a T-T-top.

[It is likely that the support for your the T-Top is] screwed into the deck with undersized hardware for the load. The T-Top places a large load with wind and sea state on the attachments. If your console is moving at slow speeds then you have a problem.

One option would be to remove the T-Top and secure the console.

[jimh]

The fundamental nature of the Boston Whaler Unibond hull prevents post-molding installation of embedded reinforcement materials into the Unibond hull such as a simple backing plate, as there is no access to the underside of the cockpit deck surface.

Attempting to attach structures to the cockpit deck such as a large wind-area T-Top will produce very significant forces at the attachment points, and those areas are not designed to tolerate those forces and will not be able to hold a threaded fastener as part of the attachment point.

[RaySmiley]

[I have decided] I will have the T-Top removed [from my 2003 170 MONTAUK].

NEW TOPIC

Q5: what Bimini Top is suitable for a 2003 170 MONTAUK?

I want the Bimini Top to be tall enough so I can stand up underneath it.

NEW TOPIC

Q6: where can I get a grab rail for the [center] console of a 2003 170 MONTAUK?

The original grab rail on the center console of my 2003 170 MONTAUK was removed to make room for the T-Top.

Thanks for all the advice.

[jimh]

On new topic of Bimini Tops:

I want the Bimini Top to be tall enough so I can stand up underneath it.

Q7: how tall are you?

[Jefecinco]

Carver Covers is an excellent maker of Biminis and boat covers. They have a web site at http://www.carvvercovers.comwhere examples can be seen.

[jimh]

On new topic of sources for OEM parts for Boston Whaler boats:

Q6: where can I get a grab rail for the [center] console [of a 2003 170 MONTAUK]?

OEM components for Boston Whaler boats can be purchased from a Boston Whaler dealer.

[RaySmiley]

Q7: how tall are you?

I'm 5-feet 11-inches [tall], and I would like at least maybe a foot of clearance [from my head to the Bimini Top].

[jimh]

I'm 5-feet 11-inches [tall]…

You are not unusually tall, so I would expect all Bimini Tops would allow you to stand under them.

A Bimini Top for a 17-foot boat typically only has one main support frame. The orientation of that frame will affect the height of the frame above the gunwales.

I would like at least…a foot of clearance….

Having the Bimini Top mounted almost 7-feet above the cockpit deck sounds excessive. The less height in the top, the more shade useful it provides underneath it. Creating shade is the essential purpose of a Bimini Top.