Hobie Cat Forums

It is currently Sat Aug 27, 2016 3:04 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 10 posts ] 
Author Message
PostPosted: Sun Sep 13, 2015 2:01 pm 
Offline
Site Rank - Captain

Joined: Fri Jun 05, 2009 7:44 am
Posts: 121
Location: Philadelphia, PA
Here's a picture of what this is about, before I say why I'm building it, and what the design criteria were.

Image

It's a third, front wheel dolly that fits in the front hatch, uses the front hatch shock cords to hold it in place, and has a kind of ratchet that puts a brake on allowing only one way movement if I want that happening.

WHY--The AI 2 is heavier than the AI 1 (not as heavy as the TI) but still, if you are using the heavy duty rear dolly that Hobie sells, the bow has some real weight--especially if you have gear in the front hatch. The boat launches fine from my trailer, but if I launch with the dolly I save two trips from trailer parking to the ramp. And there are places I can't use the trailer.

Recently, on a crowded day, I was landing the boat and trying to pull it on the dolly by hand up the ramp slope quickly because there were other boaters waiting etc. Both lifting and bow and pulling uphill is doable, but not that fun. Also, If I set the bow down to rest a second, it just goes into reverse sliding away, or else I'm bending over holding it still. Anyway, on that day I decided it would help a lot to have a front wheel, and furthermore one that would not roll backwards if I so desired. With the creases in the underside of the hull as natural places for longitudinal support for the dolly, and the shock cords already there--underneath the front hatch is perfect for one.

BUILDING IT--Started by taking off the hull profile and figuring out how high I wanted the bow to be to reach my hand easily when I'm towing. That resulted in the full sized templates shown below (did the best I could to bring out the pencil lines in the pic)

Image

You are seeing one of the semicircular, longitudinal pipe supports already built here. The basic structure is 5/4" US clear pine, sandwiched between 1/4' marine ply. Yes it could have been 3/4" pine as well in terms of strength, but that gave less bearing surface where the mount hits the hull.

This is one of the test fits

Image


I cut out parts of this template to outline the band saw cuts on the wood, and then tape them back in place afterwards. Here's a dry fit clamp up of the central section before gluing the three pieces of 5/4 together to get the necessary width.

Image


Below, the marine ply has been added and a test fit shows the profile to be pretty good. The white pipes fit in the hull creases which are just about parallel at this point.

Image

Above you can see how the marine ply on the semicircular longitudinal supports extends vertically upwards to create a cradle for the pipe. I'll put rubber on the part that hits the hull directly--the same stuff Hobie sells for the TI cradles (or did sell anyway).


Here's two more shots of the thing mounted.

Image

Image


Works great in the driveway, and I should be able to try it on a launching ramp tomorrow. Below it is stowed away in the front hatch. It just fits (made that way on purpose)

Image

And now here's the simple, funky ratchet gizmo, shown below first in action, and then stowed off to the side.

Image

Image

Since the dolly itself is symmetric fore and aft, I can turn it around and get this braking action in either direction if I want it. It's easy enough to lift the boat in order to make turns, and going downhill on a ramp, it's easy enough to just life the bow also. So that means I can just set the bow down and park the boat heading down hill if there's congestion on the ramp area.

After some more testing, this whole thing will get one coat of MAS epoxy, a light sanding, and then one or two coats of Epifanes varnish. Have really enjoyed building this, and I love it that the same shock cords that hold the hatch cover down can hold the dolly in place. That is so perfect. :D


Top
 Profile  
 
PostPosted: Sun Sep 13, 2015 10:45 pm 
Offline
Site Rank - Deck Hand

Joined: Fri Mar 13, 2015 1:52 pm
Posts: 12
Location: Concord, California
Mikereddy
Wow, That's too cool. I have trouble getting mine on the trailer. I've been thinking about a second set of wheels to give me more places to launch. Great mod
Mike

_________________
Papaya 2015 AI


Top
 Profile  
 
PostPosted: Mon Sep 14, 2015 2:53 am 
Offline
Site Rank - Captain

Joined: Sat Jun 06, 2015 4:30 am
Posts: 110
Location: Delnor Wiggins, Fl Peters Twp PA
Nice work!!


Top
 Profile  
 
PostPosted: Tue Sep 15, 2015 3:49 pm 
Offline
Site Rank - Captain

Joined: Fri Jun 05, 2009 7:44 am
Posts: 121
Location: Philadelphia, PA
Thank you very much BobAgain and mmmckey.

Let me know if you are thinking about building anything similar. I might be able to send you the profile of the hull at that point.


Top
 Profile  
 
PostPosted: Wed Sep 16, 2015 7:59 am 
Offline
Site Rank - Old Salt

Joined: Sat Nov 06, 2010 8:10 am
Posts: 660
Location: Satellite Beach, FL
I have been thinking about doing the exact same thing but something simple like this.
DIY Bulletproof Kayak Cart
Image

_________________
Zach


Top
 Profile  
 
PostPosted: Wed Sep 16, 2015 11:37 am 
Offline
Site Rank - Deck Hand

Joined: Mon Aug 31, 2015 7:03 am
Posts: 14
mikereddy, that is nice.

I just picked up a TI last week and after launching it a few times I wanted something similar. I am planning to use the boat trailer as the base, and I was thinking of using a trailer dolly for the third wheel:

https://duckduckgo.com/?q=trailer+dolly ... a=products

I would love to have a hand brake on that dolly, maybe activated like a bicycle brake with a lever on the dolly handle. That would allow me to slow the beast down as it rolls down the ramp and keep it from rolling in the wrong direction (much like your ratchet gizmo). But I haven't found a dolly with a hand brake yet.

Any suggestions?


Top
 Profile  
 
PostPosted: Wed Sep 16, 2015 3:45 pm 
Offline
Site Rank - Old Salt

Joined: Mon Aug 04, 2014 8:17 pm
Posts: 353
Location: Austin Texas
Mike I'm toying with something similar and wondering how you get the wheel under the boat and keep it from flopping over when installing it on land ? Or do you install it in the water and rely on it's flotation to hold it in place while you put the straps on ?
Nice design !
Thanks


Top
 Profile  
 
PostPosted: Wed Sep 16, 2015 5:39 pm 
Offline
Site Rank - Deck Hand

Joined: Mon Aug 31, 2015 7:03 am
Posts: 14
Deleted duplicate post.


Last edited by dvt on Thu Sep 17, 2015 8:34 am, edited 1 time in total.

Top
 Profile  
 
PostPosted: Thu Sep 17, 2015 4:50 am 
Offline
Site Rank - Captain

Joined: Fri Jun 05, 2009 7:44 am
Posts: 121
Location: Philadelphia, PA
mmckee--I forgot to ask you: when you say you have trouble getting it on the trailer, do you mean retrieving from the water?? I guess so.... or do you mean from a dolly back onto the trailer?

PurdueZach--that "bullet proof" dolly looks just fine and is probably easier to build than what I did. I love doing woodwork, and I love shaping things in the form follows function way. I do think the front end of the AI 2 is a bit heavy with only the rear Hobie dolly in place. Can you disassemble that "bulletproof" thing and put it in the front hatch? Remember, any front dolly that does not swivel will require you to lift the bow in order to make turns.

Buckaroo--I haven't yet tried to install it in the water, and I'm not sure how that would work. On land, the weight of the boat holds it in place while only one piece of shock cord is pulling on it. No problem there. You can't fasten both pieces of shock cord at the same time--at least I can't reach that far. But in water, it's not clear to me that the buoyancy alone would keep the first piece of shock cord from pulling the dolly sideways out from under the boat. I can perhaps test that on Saturday. Or maybe not, because I think I want to seal the wood before dunking it. I basically put the rear dolly on in the water, pull the bow out of the water, and then install the front dolly


Top
 Profile  
 
PostPosted: Thu Sep 17, 2015 5:59 am 
Offline
Site Rank - Old Salt

Joined: Mon Aug 04, 2014 8:17 pm
Posts: 353
Location: Austin Texas
Oh, so you lift the bow with one hand and place the wheel under and it stays in place without flopping over ? Thanks, I'll be curious to hear what you find out after using it a bit.
I'm wondering if it might be easier to use a strap through the frame and bring the wheel under from the front while holding the strap looped around the hull ?

On the PVC cart: I recently modified one of those I had built for my Revo to turn it into a scupper cart. The spacing wasn't quite right so I mostly replaced the frame and salvaged the wheels and axle. I was curious to see if I could make it strong enough for the TI. In the T's that the axle runs through I put 1"x1/2" reducers in all four places then glued in a short piece of 1/2" pipe in the reducers. Then I bored out the 1/2" to 5/8" , my SST tube axle size. It feels really strong but I haven't had a chance to try it on the TI yet. I may try building one with a 1" axle for the TI or use a similar setup for a single front wheel. In the picture there's an extra piece of bored out 1/2" next to the wheels just to make up the space on my original axle. It also needs the short cradle or a pad for under the hull.
Image

Chris


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


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