Would a TI with the main hull full of water still float?

Just wondering if a TI would float if it's main hull was ruptured by hitting reef, shark attack, bung left out etc and would it be sailable?

By definition, every Hobie must have sufficient built-in buoyancy to remain afloat when fully flooded. However, this legal requirement does NOT need to also support the weight of any people on board. Please also note that this refers to the main hull only.

However, my tests have shown that each ama requires approximately 330 pounds to push it below the surface, so a fully equipped TI would not sink unless the combined weight of crew and equipment exceeded 660 pounds.

However, in answer to your other question, whether a TI would be sailable with the main hull full of water, I would tend to think that the buoyancy of the amas would make progress possible, but painfully awkward.

I have inserted half a dozen pool noodles inside my hull, the additional buoyancy of which would hopefully improve that scenario at least slightly, but realistically, as long as you ensure the bung is in (make a launch checklist if you have a bad memory), the odds of breaching the hull on a reef are minutely small (the hull material is far more flexible than say glassfibre, so it will not normally crack), and the odds of a shark actually biting through the hull are even smaller (you have a one in three chance that the shark will pick the main hull LOL).

I am highly confident to take my TI offshore, as I believe the hull material, the three hull design, and the ability to instantly reduce sail area, make the vessel a far safer prospect than the majority of power boats you see heading out there.

_________________
Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

I agree with Tony that the TI (and AI) are more safe than the vast majority of skiffs and small power boats. Still, I have a friend who said his TI almost sank twice. His wife did not like it. He sold it. There has been talk on the forum that the TI "flexes and breathes." That is a little bothersome, because it leads to water intrusion into the hull. This problem is going to happen when you are in choppy, rough waters--not good. Many tandems loaded for camping with a couple large passengers may be overloaded. While a tandem may not sink, I don't think you want to be anywhere near that situation. I flooded my AI hull and, quite easily, made it a mile to shore. This is pure speculation on my part, but I wonder if the TI is made a bit "flimsy" to keep the weight down, which can lead to the flexing. I've never had that feeling with the AI. Now the new AI is coming out and weighs 27 lbs more than previous models--much of the additional weight is in the hull (104 lbs.) Hopefully, some of the extra weight has gone into beefing up the AI in all the right places--mast base area, transom/stern/rudder attachment, and mirage drive area. I have not heard of AI problems in the mast area (problems which seem to be common in the tandem.) I hope the larger & modified sail does not cause problems on the AI.

Just some thoughts (which will likely get me in trouble with the TI crowd.)

Keith

_________________
2015 AI 2, 2014 Tandem

"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

"Less is more" Anon

Keith, I wish you had pointed to where this "TI breathing and flexing" is mentioned in the forum. I can only recall some people talking of finding a few gallons in the hull after a vigorous sail, and this seemed to be related to front hatch sealing, and seemed to occur with both AIs and TIs. I think your assertion that somehow TI hulls are less sound than AI ones is questionable.

I stand ready to receive comments from all those who agree with you.

_________________
Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

We have been known to grossly overload our TI when we go out snorkeling with our TI just offshore in Key West(always close to shore (no more than a mile or two out), and always in nice calm weather). With 6 adults (way over a thousand lbs) the round hatches in front of each seat are typically underwater. The boat sails fine but is a bit sluggish, in that situation I typically just use my motor, and pedal to get out and back, usually when we do that kind of stuff there is almost no wind anyway. I always carry 6 life jackets on board. The boat does take in a little more water than normal, but never more than a gallon or two.
I have a feeling if the main hull breached and filled with water (very unlikely), you could still get back to shore, but it wouldn't be fun, getting the boat on your trailer when full of water would be another matter ( LOL).
It's surprising how durable the PE hull are, we have banged into and bounced off quite a bit of stuff with ours, and never had any issues.
Bob

Tony! How can I get anyone to agree with me! I'm the last AI owner left. I was trying to avoid searching for the breathing/flexing of Tandem hulls, but I'll give it a try.

Keith

_________________
2015 AI 2, 2014 Tandem

"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

"Less is more" Anon

Tony,


A quick search turned up the above quote and I really don't want to try to find more, but I believe I could. Besides, I don't think I need a better authority than fusioneng.

Keith

PS If you need to find the location of that quote, just do a search on fusioneng and a few key words like "flexing" "leaks" "bends". It was in a discussion of strengthening his bow to handle his jib.

_________________
2015 AI 2, 2014 Tandem

"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

"Less is more" Anon

Keith, it is all in good spirit, but it is telling that Bob, who was the source of your quote, has also posted hoe much confidence he has in his (overloaded) TI, and his comments regarding the weak point of the hull being where the larege opening is for the front hatch - as it relates to the extra stresses applied to the hull by adding a jib and/or spinnaker. As the hatch opening on both TI and AI is similar in size, there is no evidence that the AI is less flexible in this area.

Spending some idle time with Hobie Island specs and my calculator, I find that the hull weight to length ratio of the TI is 6.14% greater than the AI, suggesting that the TI hull walls are not thinner than the AI.

Rest me case!

_________________
Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

Yes, definitely all good fun. Still, the measurement that counts is either the length from the front x-bar to the bow point OR perhaps from the center of the front hatch to the bow point. If these distances are the same in the TI as the AI, I agree, no difference. But, if the TI is longer, that could be a source of significant difference. I only have an AI and can't make the measurements. But, I did a quick and dirty measurement from the center point of the front hatch opening to the bow point: 43 3/4 or 44" (111.1 or 111.8 cm). You can measure your TI.

I guess the other important measurement would be the size of the front hatch opening on an AI & TI. If the TI were larger, and it may well be, that could weaken the bow area and result in more flexing. Next time I'm out with a TI friend, I'll compare the 2.

Also, as I mentioned earlier, my friend, who had a TI, felt strongly it was not safe and sold his. Just anecdotal but real. Probably people have said the same about the AI.

All of this may be moot once the model 2015 comes out. My guess is that the bow area will be strengthened with the intent of bring out an AI jib.

Keith

_________________
2015 AI 2, 2014 Tandem

"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

"Less is more" Anon

Well there ya go Keith! The distance from cross bar to bow is four inches SHORTER on the TI! This makes sense when you consider the TI has to fit a second crew position, which is much longer than the difference in overall length of the hulls.

I have not measured the size of the front hatch, but would be surprised indeed if the TI one was bigger, given the above measurement.

I am perplexed about your friend's reaction... I would love to find out exactly what he perceived the problem to be. I have put my TI in situations which had my full attention (!!!), with zero concerns that the TI was going to let me down.

_________________
Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

I'm not sure we have the same measurement. Mine was from the center of the hatch opening to the tip of the bow.

I was disappointed that my friend sold his TI, because it is tough to find people who like to camp and have an AI/TI. Nevertheless, I don't think you would like to hear my friend's comments about the TI--they were quite negative.

I'm headed to bed. We have company, and I'm not getting enough sleep!

Keith

_________________
2015 AI 2, 2014 Tandem

"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

"Less is more" Anon

Thanks for the advice guys, might have put the AI cat amongst the TI pigeons
Have a bad case of 'WA shark paranioia' and will be sailing off Busselton West Aust. where there has been a few fatal attacks lately.
Planning on sitting in the front seat with the trampolines on so I should be safe

Ha, I suspected your question was shark-related! While the existence of great whites and numerous attacks in WA is well documented, I have never heard of a great white biting a kayak, or jumping out of the water to grab a kayaker. Besides, as I said above, it would be insanely unlikely that a shark would bite one of your hulls, and even more unlikely that it would choose the middle one. I would take more care driving to the launch site, as the risks are greater during that phase of your trip!

Enjoy your TI or AI (really, they are both very close siblings, despite appearances sometimes that it is an us and them thing), and you will have a ball.

_________________
Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

I think moving forward with the new improved AI design the AI sales will pick up again. I put the new AI on equal footing with the TI (all the right stuff). For a family boat the TI is hard to beat.
Of course this is all just my opinion.

Owning both an AI and a TI I have every confidence in both hulls. I would say it would be very difficult to sink either due to the built in flotation, and the 2 ama.

That said the TI does suffer from more flexing/oil canning than the AI, probably due to the larger volume of the hull. There are places on the AI that I can kneel on with no hull distortion yet on the TI those same positions cause significant distortion.
I don't consider this a safety issue though as flexing is a long way from actual hull breaching.

In this short clip the bow hatch opening flexing can be clearly seen.


This was the source of water ingress that was fixed by adding a simple spray cover, seen in the pics below.



On my to do list is a reinforcement on the inside of the hatch lip that would strengthen it and stop the lip bending inwards, which creates a gap between the hatch seals and the inflexible hatch lid. The spray cover stopped virtually all the water getting in so I haven't bothered with the reinforcement.