Check your V Brace / Mast Receiver set screw , I did not

New 2015 Ti

Is it going to be flush with bottom of kayak hull ??

Hi Matt
Would you please also post a description of exactly how to set up the mast receiver.
Ie what order to tighten the V-brace, Centre set screw nut etc and how tight each of these should be. Additionally should there be any gap between the forward lower edge of v-brace bracket and the hull?

Note: I also found my v-brace bracket to be loose allowing fore and aft movement when only light pressure was applied to the mast. Hence I would like recommendations from hobie on how to tighten this correctly.

_________________
Dune Tandem Island owner as of June 2013

+1

_________________
Paul

2013 Tandem Island

Hello..... ?

Sendt fra min A0001 med Tapatalk

Yep, these days we check every single one of them that we sell and so far the majority haven't been tight enough for my liking. Same goes for the bolts that secure the crossbars into place (especially the front ones, given how much load that fwd xbar is under while tacking or jibing).

_________________
Kayak Fishing Specialist: SLH
https://slhobie.com.au

I was able to tighten the mast receiver set screw on my new 2014 tandem a bit. The xbar bolts seemed ok.

Keith

_________________
2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon

I had this problem this past summer on my 2015 TI. I had just towed 2500 miles and had sailed maybe 4 hours on the lake when the mast came loose. Called local dealers without much success. Finally took everything apart and reassembled and tightened the nuts. Everything ok since even after towing all the way home.

Although I have not been able to inspect in person yet, my uncle tells me the black plastic piece that fits between metal v brace plate and the hull is missing (he heard a bang and the mast became unstable). The stud and nut were sitting in the metal hole of the vbrace, but there was nothing between the metal plate and the hull. Is that black plastic piece part of the mast receiver (meaning the mast receiver part actually broke? Is there a nut in the hull that the stud screws into below the black part, or is it actually screwing into the black part?

Galager,
The mast receiver is one piece. You can see a pic of it by using the parts finder here:
https://www.hobie.com/parts-and-accesso ... 1489782536
The mast receiver may not be broken as it could have just slipped out of place?
The stud goes through the v brace base plate and mast receiver 'toe' and into a thread in the brass molded-in hull fitting.
You will need to remove the broken stud from this brass fitting and replace it with the upgraded stronger slotted head stud.

Thanks for bringing up this old post. It was a timely reminder to do a walk around and check for issues. My xbar bolts needed a little firming.

Cheers
John

The area around that little stud at the base of the mast holder is the highest stress point in the entire design.
Leverage plays a large role in the amount of stress in this area, and the stress on that little stud. Think about it, you have an 18ft pole held 1ft from the bottom (where the delrin bearings are). If you equate this to lifting a car with a lever, imagine taking an 18ft pole placing a brick 1ft from the end, then lifting your car (a small car) with one hand by pushing down on the long end of the pole. This amounts to several thousand lbs of force (under the right conditions of course) applied to that little stud and the walls of that little brass insert in the forward/back direction, (the brass insert is embedded inside a pyramid that is molded inside the hull, the pyramid takes the bulk of the force))
When adding massive sailsets to my original TI (back in 2010) I of course tested everything to determine all the potential failure points (I'm a design engineer, lol, thats what I do), I was able to pull the main control line tight with the sail completely unfurled, just a quick tug on the control line snapped that little stud ( the old stud design)as if it wasn't there at all. The 'side to side' force (structure is strengthened by the V-braces) posed no problems.
Obviously if your not planning to add giant sails (ie... jibs, spinnakers, wings,etc), there is no need to do anything, the built in stud (if it's tight, and working), and the mast strength is all within the design spec's of the mainsail forces. Just make darn sure all the bolts and pieces remain tight.


However when adding say a 135 sq ft spinnaker, and/or a 35sqft jib to the design, those big sails generate way more force than the original design can withstand. The strength of both the mast itself, and that little stud at the base of the mast holder are greatly exceeded.
On all my designs I added a small aluminum plate inside the hull that fits between the back of the mast holder, and the front of the mirage drive well, I then made a small dam around the bottom of the hull around the mast base, and poured epoxy into that area, ( the alum plate is buried in epoxy), all completely removable of course. All my designs include a rear stay line that only allows the top of the mast to bend forward no more than 1ft, (the rear stay line prevents the mast (and stud) from breaking when the big spinnaker is deployed).
You can reason it all out yourselves, lets say for example you are in 20mph plus winds, you open up the main and spinnaker showing around 220sq ft of sail area, the boat is easily propelled to 20mph, now go to one of those online calculators that calculate how much horsepower is required to propel a displacement hull to these speeds, (required horsepower goes up exponentially with speed it appears). According to my calculations anyway, the horsepower generated by the sails alone is in excess of 20hp (maybe more). The boat as shipped from the factory is not designed to withstand those loads, (lol, actually no part of the design, (ie... mast system, the hull itself, AMA's and AKA bracing, rudder, etc, etc, etc).
I'm not suggesting anyone not add additional sails to their TI's, or not to mod your boat out, (it's your boat do as you please). I'm just saying if you are planning to do so, you need to understand the forces involved, and the limitations of the current design, then work around them.

Bottom line is the most expensive repair on the boat is if that little brass insert at the base of the mast gets pulled out or damaged beyond repair, this scraps out the entire hull, you will need a new hull (expensive), so in my opinion that little stud and the V brace system should be inspected periodically. No need to do anything drastic (designwise) if the boat and sail system remains stock (what most prefer), in other words the design is sound on the factory stock TI, as long as everything remains bolted together and tight.
Sorry I'm an engineer, I tend to over explain things...
Hope this helps
FE

One Turnbuckle Nut was only finger-tight on my AI2 when I went looking for the "Clunking" noise the mast was making, there was no sign of Loctite on any of the nuts. "Clunking" continued, maybe this is it? Will check.

_________________
Fair Skies, Max.

Can you tell me which part is the "Set Screw", I only see bolts and nuts in the photos? Thanks.

_________________
Fair Skies, Max.

Yes Max, a clunking noise on tacking is usually due to loose X-bar bolts.
The setscrew or stud is located at the bottom of the V-brace. In the pic above it has a slotted head, visible above the locknut. It screws into the brass hull fitting and provides a thread for the locknut which pulls the Brace and mast receiver down over the hull ‘nubs’
This stud needs to be tight in the brass hull fitting, as does the locknut. To check it properly you need to loosen the locknut, then check the stud tightness, then tighten the locknut.
The slotted head indicates it is the upgraded stronger stud. Earlier studs had a standard hex head.
It is vital that both stud AND locknut tightness are regularly checked as looseness can lead to a catastrophic snapped stud and mast receiver fail.

Good old Stringy to the rescue.

Thanks for explaining that so clearly that I now know how it works and what to look for.

I have some Red Loctite I guess that will be better than none?

In the aviation world it is reasonable to expect more issues with a brand new Aeroplane than one that has flown for 100 hours and had all the minor bugs ironed out, I guess it's the same with boats.

_________________
Fair Skies, Max.