Hobie Cat Forums

It is currently Tue Sep 16, 2014 11:48 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 26 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Fri Mar 25, 2011 4:19 pm 
Offline
Site Rank - Deck Hand

Joined: Sun Feb 25, 2007 4:59 am
Posts: 17
Location: Sydney, Australia
Being a former AI owner for 2 years and now a TI owner since May last year, I have been forced to come up with a suitable way to getting the boat around on my car rooftop, and single-handed at that. I always launch off sandy beaches usually no more than 200 metres from the car. With the AI I used an extension bar to the rack but this proved way too tricky and downright dangerous to the boat and me ( I'm 60..sigh :( with a dicky back!)
After quite some reflection on how to improve the load/unload I came up with a list of features I needed ....
1) NO heavy lifting to get the hull on or off the car. Side access being my preferred method.
2) Must not in any way risk damage to ends of the hull, as was the case when using the extension bar technique, ie scraping the end corners!
3) Hull must be upside-down on the rack, the Hobie (and mine) preferred storage way.
4) The boat is easy to get right-side up or back.
5) Must be able to install my wide stance kart ( with 32cm Wheeleez tyres ) while the boat is still on the carrier. See Rule 1.
6) Must be able to open the boot ( that’s the trunk to you Yanks!) with the boat on the car.
7) Mounting rails must be at least 2 metres apart to give a safe load distribution negating the need for end ropes. My car’s racks are only 90cm apart, not good!
I believe I have met all these criteria, for me, on a sedan car, at least.
As I’m an just an amateur welder, construction was to be from square steel telescoping tubing. Aluminium was not an option for me, so weight vs strength was of great importance.
Two longitudinal bars bolt onto the roof racks on which the main carrier sits on top of and is hinged to one side of it.
Image

Image

After unstrapping the hull, 1st job is to install the horizontal and angled bars, which slide in and are pinned.
Image

Swapping end for end twice I lift and swing the hull over to the outside.
Image

Using a specially made tube with right angled gate post hinge pieces, the frame hoisted up to the limits set by the two guy ropes. There is no weight lifting here, the amas and mast perfectly counter balance the hull!
Image

Image

Now it is locked in place with the bar.
Image

Now it is a simple task to just roll over the hull onto it's bottom.
Image

Image

Whilst in this position I insert the Kayak Kart, pinning the posts from above to keep it attached. Then the boat is just lifted off the bar sideaways to a very short distance from the ground. Two 10Kg weights are then hung on the outside of the bars to counterbalance the amas/mast weight, and then the frame lowered to get them off.

Once assembled,
Image
my TI is wheeled down into the water deep enough to allow me to push down on the axle bar till it drops out of the hull and bring to the side, the kart is then disassembled and put inside the front cargo hatch. Then off we go for another great day's sailing in our much loved Tandem Island, Thanks Hobie, you guys are fabulous! :D

_________________
Image
If you think nobody cares if you’re alive, try missing a couple of payments.
Had: Mirage Tandem, Outback, Adventure Island
Have: Tandem Island


Top
 Profile  
 
PostPosted: Fri Mar 25, 2011 11:18 pm 
Offline
Site Rank - Old Salt

Joined: Fri Jan 05, 2007 9:21 pm
Posts: 2229
Location: Maui, Hawaii
WOW!!!
Very well done!

_________________
Image
http://KayakingBob.com - - - - - Hobie Island Sailing since 2006 - - - - - 2011 & 2012 Hobie AIs and a 2012 TI


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 1:52 am 
Offline
Site Rank - Old Salt

Joined: Fri May 08, 2009 5:06 am
Posts: 1577
Location: Lake Macquarie NSW AUSTRALIA
Very cleaver Hobienutter. This isn't even a variation on a theme is it, because I can't recall anything like this on the market or been done by others. Great bit of work. Hope to catch up and have a good look in the flesh on the 17th on the Harbour if you're there.

_________________
Image

Don't take life too seriously................it ain't permanent.


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 2:33 am 
Offline
Site Rank - Old Salt

Joined: Fri Dec 05, 2008 2:32 am
Posts: 1785
Location: Calga NSW, Australia
Sweet, HN. Is that Lyne Park in Rose Bay where the photos were taken?

_________________
Image


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 3:25 am 
Offline
Site Rank - Deck Hand

Joined: Sun Feb 25, 2007 4:59 am
Posts: 17
Location: Sydney, Australia
Helloes to Slaughter and Chrisj, I haven't based my rack on anything I've seen, purely on a practical needs basis :idea: . I must admit that I didn't even look deeply to see what others have done, most seem to use the side bar trick or sliding it off the end of the vehicle with many a bad gravel rash as a result.
The photos were taken at Balmoral. I also launch at Rose Bay and Vaucluse Bay, but I'm looking for other possibilities further up the Harbour as well. Know of any good ones? 8) Cheers, Hobienutter

_________________
Image
If you think nobody cares if you’re alive, try missing a couple of payments.
Had: Mirage Tandem, Outback, Adventure Island
Have: Tandem Island


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 4:42 am 
Offline
Site Rank - Old Salt

Joined: Tue Jun 19, 2007 6:14 pm
Posts: 1881
Location: South Florida
Very impressive, Hobienutter. Smart execution of a cleaver idea.

However, I have a question: I see a trailer hitch on your car--why didn't you just use a trailer?

Keith

_________________
I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"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


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 5:40 am 
Offline
Site Rank - Old Salt

Joined: Tue Oct 31, 2006 6:06 am
Posts: 360
Location: Turks and Caicos Islands
Nice setup.

I was wondering if there is some way you could take a line from your angled pieces and a couple wraps around something on the car, then you could just slip the line when you wanted to return it to horizontal. would save you from having to cart two 10 kg weights around.

_________________
Island life in the Devil's Triangle:
http://2gringos.blogspot.com/


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 6:57 am 
Offline
Site Rank - Old Salt

Joined: Thu Feb 11, 2010 12:07 pm
Posts: 1047
Location: Ontario, Canada
That's a great looking system. My only concern would be the Thule (?) roof rack that you're using. From what I can tell, a Thule Roof rack on a pre 2007 Toyota Camry is only rated to hold 165 lbs. I'm looking into converting a boat trailer into a custom AI/Revolution trailer with a cargo box as well. The whole trailer should weigh less then 300 lbs and take the boats out of the wind, which should actually give me better gas mileage.

But the biggest reason that I want a trailer is because everybody that I've talked to about roof racks is telling me that the Racks aren't designed to hold onto the car with that much weight on them.

Your system looks fantastic, but your weakest point seems to be the attachment to the car. I'd be very very careful, that's a LOT of weight up there, and with no bow and stern line, if one of those feet breaks free from your car, you're going to lose a big boat.

At the very least, I'd use a bow and stern line just to keep the boat attached to the car if one of the feet on the Thule rack fails.

Maybe I'm missing something, but I think it's worth looking into.

_________________
Image


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 7:41 am 
Offline
Site Rank - Deck Hand

Joined: Sat Aug 28, 2010 12:55 pm
Posts: 5
Location: Poland - Europe
I have this system...


on this car: Image

A lot of kayaks :) Image


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 3:24 pm 
Offline
Site Rank - Deck Hand

Joined: Sun Feb 25, 2007 4:59 am
Posts: 17
Location: Sydney, Australia
Keith wrote:- "However, I have a question: I see a trailer hitch on your car--why didn't you just use a trailer?"
I have never considered trailers very handy for my situation, right back to when I sailed a 14' dinghy, which I car topped as well. Way too limited in places to park, very much limits you to boat ramps which I find often way too slippery and a two person launch. With just my car I can go anywhere, anytime.
With this rack I can still bring it out to the side when parked between cars, rotate and put it back, then slide it down over the boot if necessary, but I haven't had to yet.

Augang wrote:-"Your system looks fantastic, but your weakest point seems to be the attachment to the car. I'd be very very careful, that's a LOT of weight up there, and with no bow and stern line, if one of those feet breaks free from your car, you're going to lose a big boat."

Believe me, I did think long and hard on this topic. I'm from an engineering background and know that these limits have a 2 or 3 fold safety margin to allow for G Forces the vehicle can impart in the load. That's why I decided to securely bolt the longitudinal bars to the racks, This makes all four footings effectively work as on giant mount rather than four independant ones. This has been borne out twice on the road when I have had to brake VERY heavily when a couple of Bozos cut in front of me and then suddenly braked hard. Not the slightest movement of the rack or damage to the roof was found. I am VERY confident with this setup. More than I believe I would be with a trailer. In Sydeny traffic you would run a pretty good risk of the boat being rear-ended by a gawker.

Gringo wrote : "I was wondering if there is some way you could take a line from your angled pieces and a couple wraps around something on the car, then you could just slip the line when you wanted to return it to horizontal. would save you from having to cart two 10 kg weights around."
I had considered a post with a pully system or gas lifts, but they have been proved entirely unnecessary.

Appreciate all you guys concern and interest, Peter

_________________
Image
If you think nobody cares if you’re alive, try missing a couple of payments.
Had: Mirage Tandem, Outback, Adventure Island
Have: Tandem Island


Top
 Profile  
 
PostPosted: Sat Mar 26, 2011 9:41 pm 
Offline
Site Rank - Captain

Joined: Wed Oct 27, 2010 6:29 am
Posts: 121
Location: Sydney, Australia
Excellent system.

I'd like to be able to do something like it.

_________________
H@mmer
"Intelligence is nothing without imagination"
Image


Top
 Profile  
 
PostPosted: Sun Mar 27, 2011 2:05 am 
Offline
Site Rank - Captain

Joined: Mon Oct 18, 2010 9:39 am
Posts: 51
I have the same system as Moses. They aren't cheap, but one of the few products that seem to be made in the UK so at least no distribution cost if you on this side of the pond.

I have 2 short L brackets with mine rather than a cradle. I have put some marks on the rack so it is quick to move the L brackets and adapt to take my AI or Scanoe. Both can be loaded solo and are lifted on to the top of a VW van! An impossible feat otherwise. What have you done moses for the akas :?: At the moment I stick them inside the van. The mast sits on top of the AI under the straps.

I had looked at these racks for years, but never bought one due to cost. Finally I went for 1 as it was the only way I was going to be able to paddle solo, and it was worth every penny. It at least will follow me from vehicle to vehicle as fixes to the vehicles roofrack. I also now will go out for an hours paddle, as the hassle of loading has gone.

Well done on the homegrown rack. Looks ideal.


Top
 Profile  
 
PostPosted: Sun Mar 27, 2011 8:14 am 
Offline
Site Rank - Captain

Joined: Tue Feb 15, 2011 9:23 am
Posts: 59
Location: Kailua, HI
Great job with your design. Good pictures. I know that there are people out there who arent sure they can handle the TI without a trailer and this is the kind of thing that shows how a little ingenuity (actually a lot in this case) can overcome a problem.

If you concieved and welded that thing up I am sure you will be able to tell if you need to worry about the car attach points. A weight "rating" for a car rack surely contains a "safety factor" padded into any published number.

The question is how much? Anyone got a junk yard nearby that would let you put a rack on a similar car and load it up with weights to failure? :)

It looks like you have a little flex in the lengthwise members that attach to the car rack in the first pic or is it an optical illusion/photo distortion?

Again great work, Aloha

_________________
2011 TI


Top
 Profile  
 
PostPosted: Sun Mar 27, 2011 12:47 pm 
Offline
Site Rank - Deck Hand

Joined: Sun Feb 25, 2007 4:59 am
Posts: 17
Location: Sydney, Australia
Hi Tiki Taki, thanks for the interest. The "loaded" side bar was in fact flexing :oops: as I had run out of tube of the strength I needed and used one I thought "might" do the job :( . Proves that i should stick with my original plan. I have since replaced that side bar with a stronger one. Peter

_________________
Image
If you think nobody cares if you’re alive, try missing a couple of payments.
Had: Mirage Tandem, Outback, Adventure Island
Have: Tandem Island


Top
 Profile  
 
PostPosted: Sun Mar 27, 2011 2:36 pm 
Offline
Site Rank - Old Salt

Joined: Thu Feb 11, 2010 12:07 pm
Posts: 1047
Location: Ontario, Canada
Tiki Tack wrote:
A weight "rating" for a car rack surely contains a "safety factor" padded into any published number.

The question is how much? Anyone got a junk yard nearby that would let you put a rack on a similar car and load it up with weights to failure? :)


As I understand it, it's not the weight that's the problem. It's the G- forces. G forces in a regular emergency stop can equal 1.5 times the force of gravity. If you swerve while braking, you're putting a lot of that 1.5 g's on just one footing. So if the rack is built to hold 165 lbs. and you've got a 195 lb boat up there with at least a 35 lb rack, you've got 230 lbs, times that by 1.5 for an emergency stop and it's like having 345 lbs up there. Plus the higher it is off the rack, the more leverage it has on those footings.

So it's not about the weight, it's about the shifting forces, and if you have a problem, it happens fast, and without any back up system attaching the boat to the car, you've got a boat going one way (perhaps straight for a pedestrian that you're braking and swerving away from) and your car moving the other.

"An object in motion, stays in motion."

I'm not saying it's not perfectly safe, but it couldn't hurt to put a bow and stern line since you already know you're over capacity. At least then if the rack breaks free in an emergency, the boat remains on the roof.

_________________
Image


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 26 posts ]  Go to page 1, 2  Next

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group