Hobie Forums
http://www.hobie.com/au/en/forums/

Stiffening Hobie 16
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=66602		 Page 1 of 2
Author:  Dmbsail [ Wed May 27, 2020 2:52 pm ]
Post subject:  Stiffening Hobie 16
I’ve recently had an idea to stiffen my 16 up. I thought about taking 4 strands of line and ratcheting them to the front 2 pylons, aft 2 pylons, and then 2 diagonally port aft to starboard forward and the same for the other side. I was going to Tighten them down just enough so that the two hulls act in unison better. My question is do you think bringing the 2 hulls slightly together so there under pressure and tight would ruin the boat? Would it help? What would the suspected result on performance be?
Author:  CaptObviousNC [ Sun May 31, 2020 4:48 am ]
Post subject:  Re: Stiffening Hobie 16
That might help, but I would be concerned about adding compression load to the pylons they are not designed for. I suggest fixing the root cause, first make sure the tramp and frame bolts are tight, and shim any gaps in the corner castings. Some people epoxy the frame onto the pylons, but of course that means the boat isn’t getting disassembled. If a pylon is loose in a hull that’s a bigger problem and it should really be fixed. If you just have a little play I wouldn’t worry about it unless you’re doing competitive racing.
Author:  Dmbsail [ Tue Jun 02, 2020 11:32 am ]
Post subject:  Re: Stiffening Hobie 16
CaptObviousNC wrote:
That might help, but I would be concerned about adding compression load to the pylons they are not designed for. I suggest fixing the root cause, first make sure the tramp and frame bolts are tight, and shim any gaps in the corner castings. Some people epoxy the frame onto the pylons, but of course that means the boat isn’t getting disassembled. If a pylon is loose in a hull that’s a bigger problem and it should really be fixed. If you just have a little play I wouldn’t worry about it unless you’re doing competitive racing.


The tramp is super tight and there aren’t any gaps in the frame. However at higher speeds still the leeward hull still has a tendency to want to dive. I wasn’t going to put tons of pressure of the pylons with the ratcheted lines, just enough to stiffen the whole boat up a bit.
Author:  mmiller [ Tue Jun 02, 2020 3:26 pm ]
Post subject:  Re: Stiffening Hobie 16
This is more a safety issue I think. Cross lines could entrap you under the boat in a capsize.

Stiffening the boat is first by the trampoline tension and then possibly epoxy in the corner castings to crossbars... then lastly the pylons to the castings if really needed.
Author:  speed633 [ Tue Jun 02, 2020 5:54 pm ]
Post subject:  Re: Stiffening Hobie 16
The reason your lee hull dives is because you have a hobie 16. No amount of frame stiffness will address a lack of buoyancy at the bows. Also, once the windward hull flies clear of the water frame stiffness ceases to impact boat performance, except as it relates to inertia and pitching motions.

I guess what I am saying is stiffen your boat up using the traditional methods of tramp tension and epoxy, then get your butt to the back of the boat.
Author:  jkkartz [ Wed Jun 03, 2020 3:28 am ]
Post subject:  Re: Stiffening Hobie 16
Nothin' new here guys. 40 some years ago,Mark showed up at a Fleet 126 race at Michigan City with his 16 tied together underneath with old shrouds and turnbuckles. I don't remember anyone pulling the red flag in the parking lot, but he was shamed into removing the rigging.
Author:  Tim H16 [ Wed Jun 03, 2020 9:00 am ]
Post subject:  Re: Stiffening Hobie 16
Quote:
Dmbsail said:
However at higher speeds still the leeward hull still has a tendency to want to dive.


Either move further back (as speed633 stated above) or rake your mast back a little more (that will help level out your boat).

Also, unless you are going upwind, your jib traveler should be all the way out. Balance the wind load between your jib and main. You don't want too much force on the jib at the expense of the main sail. Having too much force on the jib also helps to push down your leeward hull's bow.
Author:  SlowSL [ Tue Jun 16, 2020 12:05 pm ]
Post subject:  Re: Stiffening Hobie 16
Dmbsail wrote:
I’ve recently had an idea to stiffen my 16 up. I thought about taking 4 strands of line and ratcheting them to the front 2 pylons, aft 2 pylons, and then 2 diagonally port aft to starboard forward and the same for the other side. I was going to Tighten them down just enough so that the two hulls act in unison better. My question is do you think bringing the 2 hulls slightly together so there under pressure and tight would ruin the boat? Would it help? What would the suspected result on performance be?


I just epoxied my boat with West Marine epoxy. If this is something you would like to do to your boat, I would make you a deal on everything you need... epoxy, hardener, filler, mixing cups, stirrers, pre-configured mini-pumps, replacement rivets, etc. It was easier than I thought, took about 6 hours start to finish. There is enough left over to do 2-3 more boats.
Author:  billonthehill [ Sat Jul 25, 2020 4:28 pm ]
Post subject:  Re: Stiffening Hobie 16
Sorry to be late to this thread. I taught advanced hobie sailing in the late 80's and early 90's and have spent many, many hours repairing hobie's for our fleet and as a side job for a a bunch of the private hobie owners. As someone said, Try to fix the problem at the source. we used to do this by pulling the whole tramp frame (with tramp on but loosened) assembly up and off the hulls. We would then shim the posts buy cutting aluminum cans in about 6" strips, fold them in half, the slide that shim over an edge of each post so that half the shim is inside the foam filled post and the other half is on the outside of the post. With a rubber mallet and a couple buddies, pound the frame back down onto the hulls. Tightens it right up.
Author:  SlowSL [ Mon Jul 27, 2020 7:19 am ]
Post subject:  Re: Stiffening Hobie 16
billonthehill wrote:
Sorry to be late to this thread. I taught advanced hobie sailing in the late 80's and early 90's and have spent many, many hours repairing hobie's for our fleet and as a side job for a a bunch of the private hobie owners. As someone said, Try to fix the problem at the source. we used to do this by pulling the whole tramp frame (with tramp on but loosened) assembly up and off the hulls. We would then shim the posts buy cutting aluminum cans in about 6" strips, fold them in half, the slide that shim over an edge of each post so that half the shim is inside the foam filled post and the other half is on the outside of the post. With a rubber mallet and a couple buddies, pound the frame back down onto the hulls. Tightens it right up.


You are right, that is a great way to do it. I did that with aluminum can shims last year. It was so tight, pounding the frame on, I was scared I was going to damage the pylon shoe connection to the hulls. This did stiffen it up a great amount, but It still felt there was still some amount of slop, but probably an acceptable amount. Add the mast/rigging weight, etc. to the boat and there it was more noticeable that there was still a bit of slop. I just wanted a rock solid connection between the joints. I will say the epoxy did stiffen it up a small amount more over the shims, but you will have to ask yourself if you want to have to heat up the connection with a torch to get them apart should something need replaced. Even with an epoxied frame, mast up, but rig not tensioned, if I lift a hull while on the trailer, there is still about a 1-1/2"-2" deviation before the other hull lifts. Aluminum can shims had around 2-1/2-3", and before any shims around 4". I know a tight tramp plays a big role in this tension as well.
Author:  Tim H16 [ Mon Jul 27, 2020 7:57 am ]
Post subject:  Re: Stiffening Hobie 16
I have epoxied several H16 frames to the pylons and cross beams (along with new 3/16"x1/2" panhead SS rivets). If done properly, it will definitely stiffen the boat.

So far, I have not been able to take any of them apart, even while using dual torches, without creating more damage (like pulling the pylon out of it's bottom shoe). As a result, it has meant replacing both hulls and frame each time I have a major problem with either hull.

It would be interesting to see if any one has ever made a video of taking an epoxied frame apart.
Author:  SlowSL [ Mon Jul 27, 2020 8:30 am ]
Post subject:  Re: Stiffening Hobie 16
Tim H16 wrote:
I have epoxied several H16 frames to the pylons and cross beams (along with new 3/16" SS rivets). If done properly, it will definitely stiffen the boat.

So far, I have not been able to take any of them apart without creating more damage (like pulling the pylon out of it's bottom shoe) even while using dual torches. As a result, it has meant replacing both hulls and frame each time.

It would be interesting to see if any one has ever made a video of taking an epoxied frame apart.


That is solid info to know, I'm not sure that I've heard anyone else say one way or the other if they were able to get the frame apart or not with heat.
Author:  Carl3 [ Wed Sep 30, 2020 7:07 am ]
Post subject:  Re: Stiffening Hobie 16
TIM, was any type of mold release applied to the castings, posts prior to epoxy?
Author:  Tim H16 [ Wed Sep 30, 2020 10:14 am ]
Post subject:  Re: Stiffening Hobie 16
No I did not use any mold release.
Not sure it would have worked based on the shape of the corner casting and pylon.
Author:  Carl3 [ Wed Sep 30, 2020 11:06 am ]
Post subject:  Re: Stiffening Hobie 16
ok, just curious,
The article by Gary Willcox mentions " You may choose to use mold release agent on the inside of the corner castings"
I did'nt on my sons 16 but will use it on mine
Page 1 of 2 All times are UTC - 8 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/