Hobie Cat Forums

Hey all,

I went out to the lake last and noticed cracks below the cossbar on both hulls. Pics included:






Is this something that can wait untill the end of the season to fix?

Thanks,
Rebelback

Definitely needs to be fixed before sailing the boat. Most likely cracked through the hull flange. Assuming that's the case, it is major structural damage. It will be a fairly involved repair. I would take a look up under the hull to verify if the flange is cracked through.

sm

That is probably not a good idea. As srm wrote, it needs deeper inspection, and I'd take the hull off of the crossbars to assess and repair before sailing again.

You don't want this to happen to you - http://www.hobiesailor.com/archive/2004 ... chive.html

Please post the serial numbers ... especially the last 3 digits and letter ...

That will tell us when the hulls where manufactured ...

... but those cracks don't look good !!!

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

Based on the hull stripes, I'm guessing early '80s.

sm

Black triple stripe = White Knight = 1977

It's not "season ending damage," but it does need to be fixed before you go sailing again.

A good glass guy (Mark Modderman) could fix that in a day and you'd never know it was repaired.

Its a 78 white knight. there is a good glass guy in the club I'll try to get him to look at it.

Thanks for the responses guys and gals.

In addition to inspecting and repairing the visible damage to the outboard hull flange, I would also very closely inspect the deck and inboard side of the hull in the vicinity of the front crossbar for soft spots or signs of excessive flexing. This damage indicates that the bow of the hull was pulled heavily inboard causing the flange to break in tension. I wouldn't be surprised if there is corresponding compression damage on the deck and inboard side of the hull that also needs to be addressed.

sm

I have some experts from the club that are going to look it over tonight and see what needs to be done. i'll give an update if anyone is interested.

Please do, with pictures of the repair process as well if you can.

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Jeff
1986 Hobie 18 #13031
1977 Hobie 16 (As soon as I can get it out of a field...)

Boy, I don't know....looks pretty ominous to me. Unless I'm mistaken, it appears as if the stainless steel channel that secures the crossbar bolt to your hull is ripping its way up through the deck. The crack has formed in the vicinity of (but likely slightly behind) the trailing edge of the SS channel.

Let us know how it turns out. Good luck.

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Irie, mon....
'82 Hobie 18 SE with '85 Nationals Prism (White) sails
'73 Laser HID# 3463

Hi,

Using the palm of your hand ... rub your hand on the inboard sides of the hulls from the front crossbar forward. What you're feeling for are ripples/waves, these would indicate that the hulls have been "toeing" in.

There are several options for stiffening/repairing those hulls ...

... the best may involve installing a horizontial "sub-deck" from the daggerboard trunk forward to as far as you can reach inside the hull ... (you'll have to completely remove the hull ports ...) You can make the sub-deck out of NOMAX strips that will fit through the hull port opening, and then layer two or three layers of fiberglass cloth on the NOMAX to make the sub-deck ... 1/4" "Marine Grade Plywood" would work also

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

I'd say it is definitely an indicator that the hull has flexed excessively. Looks to me to be just forward of the crossbar anchor plate. This repair will involve much more than your basic fill with putty and fair. Make sure you take it to someone who knows what they're doing. At the very least this would involve grinding away much of the hull flange and deck and laminating a lot of new glass to rebuild the flange. You will probably also want to reinforce the hull internally in some manner.

sm

Hi,

The early production P19's had the same problem .... the hulls started toeing in from sheet tension pulling on the forestay ==> which pulls on the bridles ==> which generates vertical force vector and a horizontal force vector. Now the one doing the damage is the horizontal force vector ==> toe in !!!

We would rub the palms of our hands flat on the inboard sides of the hulls and feel for vertical ripples just in front of the front crossbar ....

This could be solved several ways .... in the P19's they installed a horizontal subdeck from just behind the front crossbar forward in the boats produce from approximently 1989 onwards. On older boats they would "Pop" the foredeck off to install a sub-deck ... or ... you can install a Nacra 6.0 bowfoil on the boat which greatly reduces the horizontal forces due to the angles that the bridles attach to the boat being "more" vertical ....

Unfortunately ... you can't "pop" the deck off a H18 ... and due to the lowwer freeboard I don't think a bowfoil would work as well either ...

Now ...

I went through the "red foam" issue ... in fact my boat had it's hulls replaced (under warrenty at the time) due to the port bow starting to fail ... so ... when I got my replacement hulls I "beefed" them up by installing strips of 1" wide X 1/8" thick cedar w/ carbon fiber tape "tacked" to them at either end so the strips could bend to match the hull curvature, then using WEST epoxy I installed them inside both hulls on both sides (inboard and outboard) ... I installed the first two strips side by side, w/ two more stacked on top of the first two ... this greatly stiffened my hulls ... though it did add some wieght to the hulls.

But even w/ a 8X1 mainsheet stack I can not go "block to block" which I could do w/ the "red foam" hulls as the hulls just deflected under the tow-in loading ...

A sub-deck would do the same thing as the sub-deck will act just like a "web" in a "I" beam ... you'll need to install a lip first (1/4 round molding?) on both sides, flat side up ... then you can install the NOMAX or 1/4" Marine Grade Plywood strips between the those strips ... now layer in two layers (or more) of fiberglass cloth & epoxy to make all the individual strips into one single structure ...

If you have question call me ... cell# (610) 717-8207 ... it's a Verizon Phone so if you have Verizon service you can call me anytime ... if not please call me after 9:00pm any evening .... and I'll walk you through my experiences and how I solved the problems ...

PS: I still race those hulls I strengthened to this day ...

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

I just went through the reinforcement process myself.

viewtopic.php?f=20&t=42597

The worst crack wasn't as bad as yours but on closer inspection I found little cracks all around the crossbar area. Fortunately, none inside. Added 2 (or 3?) layers of glass on the sides of each hull at the bracket. Added 3 sets of 4 strips of glass between the deck and sides with some going through the bracket. Hope that's enough. Took ME two months - "while I'm at it should do this too" - and I work slowly. By far the worst part was grinding off all that freakin' glue at the joints!

When reassembling realized I had cracked the port inboard stainless steel reinforcement bracket and bent that crossbar bolt. So I guess she's been stressed a bit!