Adding wings to a 1980 H18 (reinforcment necessary?)

Well, i decided to pass on the last cat i asked about b/c i did not feel comfortable with the trailer going the distances I'd need it to.
So, I am exploring other options and I have come across some solid early 80's boats.

It is clear that their have been issues with the mid-80's hull strength. Now i have read that the older(heavier) heavier boats did not have these issues. Is this b/c they are stronger or b/c they did not have wings exposing that weakness. I am wondering if i get a 1980 boat and add wings, Will i have to do the same hull reinforcements that people had to do on the mid 80's boats.

Jim

The older boats have more glass and are therefore heavier. The problem boats were built under Colemans' ownership and had serious delamination issues. Wings were never the cause of failure. If your looking for a boat with wings I suggest a magnum and not the SX. Magnum wings are smaller and stronger by design. They can be retrofitted to any 18 but are hard to find alone. I paid 1k for my '82 18 magnum with the trailer and catbox. Sails where still crisp even though I don't need or use them. Had both hiking sticks and good tramps on the boat and wings.

It would be wise to take the time to add the reinforcements, even on older boats. Why take the chance?

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

Specificly what reinforcements are ya'll doing?

thanks
Todd Hubbell
1990 Hulls with 1980 parts.....

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1980 H-18 and Jeepen.... also a little Sucbadiving

I believe he is referring to the the updated crossbar reinforcement channel. The crossbar bolts (inboard and outboard, fore and aft) as well as the shroud anchors on the original 18's passed through a bent piece of channel which fit in the underside of the deck lip. Around the mid 80's, Hobie updated this channel. The updated channel now has a "D" shaped section that prodtrudes down and allows (4) 1/4" bolts to connect the channel to the side of the hull. This helps to distribute the crossbar load between the hull lip and the actual hull, rather than placing all the load on the lip only.

Boats built within about the last 15 to 20 years have come with the new channels installed at the shroud anchors as well as on the crossbar anchors (both inboard and outboard). They can also be installed on the rear crossbar, although you will have to install port hole to do so.


sm

Not only do you want to add the anchor plates for the crossbars you also want to add extra glass to the hull/deck intersection where the crossbars connect. The older models were not built with wings in mind and the extra stress can cause a catastrophic failure of the hull. Very unpleasant.

I have to get back to work so I can't do the forum search for this. Matt Miller has written about this fix before.

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

Also have to run, 'meet the teacher' night.

Quick response is that when the H18's were being assembled, they put two small patches of fibreglass between the deck and the hull, right where the cross bars attach. That is, one patch on the left, and one on the right of each hull. There is some question (especially in the Coleman years) whether or not this 'reinforcement patch' was large enough.

Larger patches need to be applied, email me offline at lunnjohn at magma dot ca, and I'll give you more details how to do this. Or search the Forum.

Gotta go.

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2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

This confuses me! I have seen '85 or newer 18's shear off at the front bar, with or without wings. The wings attach to the crossbar, not the hull. Why would wings cause any more stress than trapezing does? The wings are just a means of trapping without a harness. The stress would be compression and I cannot see how a glass patch between the hull and topcap would displace that load at all. Please enlighten me!

I am not an engineer, just a plain and simple tax accountant, what you in the US call a CPA, but I will try and explain the issues. If others (Matt Bounds, Adrio, Jeremy at Surf City, Matt Miller etc) can help with better phrases or explanations, please chime in.

As we sheet in hard on the main, the centre of effort moves a little aft, which places more pressure on the forestay. In turn, the forestay (via the bridle wires,) pulls 'up and inwards' on the tips of the bows. This is nothing new. The only place the hulls can 'flex' is right at the front cross bar. Any movement from this motion on the rest of the hulls is more or less fixed due to the geometry of the location of the crossbars.

The same thing happens when we are sailing, and we get hit with a puff. Part of that force is applied to heeling, and part to greater speed. In other words, part will 'push' the mainsail over more, putting more strain on the standing rigging. The shrouds transfer the force to more heeling and more speed, (unless we sheet out to relieve this pressure,) but any excess will transfer to the forestay, and hence, to the tips of the hulls, causing more of the same flexing. I won't even mention wave action here.

Beginning in 1984, as I understand it, in order to make the H18 lighter, Hobie moved to a foam sandwich construction. Another aspect of the drive to save weight was the decrease in the size of the tabs. As you know, at initial construction, the fibreglass tab applied inside the hulls at the cross bar between each side of the hull and deck was only (?) 8" wide, (in a fore-and-aft orientation,) and really needs to be about (?) 15" wide. (Someone help me with dimensions here, please.) This tab acts as a reinforcement, and helps prevent the hulls from flexing too much as described above. And over-flexing, as we know, can cause interesting structural failures.

If you have buddies with newer H18's, take a flashlight and look inside the porthole, around the front cross bar. Check out the width of the tab, compared to yours. Does this do it for you?

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2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

My further understanding is that the hull failures did not happen overnight. It took YEARS of really hard sailing for the first failure to occur. So I do not want to suggest that Hobie's are not tough and well made, 'cos as we all know they are rugged and strong. That's one of the reasons we love to sail them.

However, no Hobie is bullet proof, and I consider my upcoming repair as part of normal maintenance.

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2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

I have a 1979 Hobie 18 with Magnum Wings. It was upgraded before I purchased it. It does not have the reinforced shroud anchor plate, so I’m very interested in this thread. I’ve looked at the fiberglass “tabâ€

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John Latimer
'79 Hobie18 - Magnum
Sail#4854

I believe that this is becoming even more confusing. I am pretty certain that the tabs are there to prevent the topcap from shearing off the hull, not to prevent the hull from shearing off at the crossbar. I state this as my older 18 sheared the topcap from the hull at the rear crossbar. I know this was caused by airing the boat, ie jumping waves. The impact when landing is severe as the boat falls with the wind once it breaks free of the water. That combined with skipper and crew trapezing and you've got alot of force applied to the side off the hull which transfers to the connection point of the hull and topcap. The reinforcing plates which connect the hull and topcap securely at the crossbar are directly used to eliminate this impact shearing. These reinforcements and the tabs in no way effect or prevent the bow from shearing off in front of the crossbar, which is where they break. My 81' 18 was t-boned in a race by a nacra 6.0. He hit my port hull and the pressure from being pushed sideways snapped the starboard hull in two at the crossbar. This boat had the plates and larger tabs. I have a friend that broke his bow off when caught by large boat wake coming sideways at the hull while racing with the nose buried deep to keep the stearns up. Again, I don't feel wings create any additional stress on the hulls and haven't been directly responsible for any hull breakage. This additional glass seems useless once the plates are installed IMO.