Modifying a Hullavator
Posted by: old_user on Jan-05-13 1:59 PM (EST) Category: Other Gear
Got a couple of high vehicles so bought a used Hullavator yesterday. Gas springs are worn so I plan to replace them. Has anyone replaced the gas springs with higher rated ones? Lift is rated at 40lbs so I assume each spring is 20 lbs. I was thinking of swapping in some 30lb or maybe even 35lb springs to increase the lifting power since I have heavy boats. Anyone tried this? What was your success?
Kayak Motor Kit
4-place Boat Trailer
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|Messages in this Topic|
Posted by: Marshall on Jan-05-13 3:52 PM (EST)
How old is are the units? Be careful if it they are early models. The locking pawl wasn't great on those so the extra oomph of your planned upgrade could give you an uppercut when you don't expect it.
Posted by: old_user on Jan-05-13 4:11 PM (EST)
It's an early model and I've read about the locking problems. Looking at the mechanism it seems possible that the locking 'pawls' could be bent a bit to improve the latching. McMaster Carr sells the gas springs of varying poundage in the correct length and the correct end fittings can be screwed on to them I think. I also suspect that a heavier spring would solve part of the problem that people complain about--the two hullavators not rising in parallel. One issue with replacing the gas spring is that the outer end is held in with a long rivet and there's not much room between the ends of the rivet and the outer housing which drops down over it for a standard bolt. The rivet on the inner end can easily be replaced with a bolt.
Lifting Capacity Definitions|
Posted by: guideboatguy on Jan-05-13 8:12 PM (EST)
Posted by: old_user on Jan-05-13 9:39 PM (EST)
No ratings on the existing cylinders. It was the first thing I looked for. I can't use a scale to determine the rating either because the springs are worn out. Springs are available in this size up to 130lbs.
Posted by: old_user on Jan-05-13 9:41 PM (EST)
The boat could weigh as much as 80 lbs.
Choosing Spring Ratings|
Posted by: guideboatguy on Jan-05-13 10:01 PM (EST)
Posted by: old_user on Jan-05-13 10:18 PM (EST)
I know a fair number of math teachers. They should be able to figure it out I suppose if they are willing to tackle it.
rating of gas springs|
Posted by: old_user on Jan-08-13 5:15 PM (EST)
I talked to Thule and they said that each gas spring was rated at 40 lbs. I will probably try 60 lb springs. I'm not that confident that the customer service rep was giving the correct rating of the spring since 40 lbs happens to correspond to what they say the rack will lift.
It COULD be correct.|
Posted by: guideboatguy on Jan-08-13 5:39 PM (EST)
We know that the springs need to be a lot stronger than what the rack will actually lift. There are TWO springs, so the total force is 80 pounds, and the rack is rated to lift 40. It's certainly possible that they gave you the right information. I bet it's also possible that you talked to some dummy who knows absolutely nothing about this stuff, and the 40-pound rating was stuck in their head, as you suggest.
Posted by: old_user on Jan-08-13 6:16 PM (EST)
It could be right. And the number didn't just come immediately to the rep's mind. He left the phone to investigate the question and came back to tell me that Thule does not sell replacement gas springs but a 40lb spring would be needed. So it appeared that someone somewhere was familiar with the problem of failing gas springs on the Hullavator.
Posted by: old_user on Jan-20-13 12:45 PM (EST)
Thule provided inaccurate information. The original springs were clearly not rated at 40 lbs. I bought two 60 lb replacement springs and installed one. The power of a 60lb spring is considerably less than the power of the originals. It takes less than half the effort to 'cock' the Hullavator with a 60lb spring. I've sent an e-mail to Thule with a complaint regarding their information. I was told 40 lbs on the phone and 40lbs in a separate e-mail. It took quite a bit of effort to replace the original spring and I am not happy since I acted on misinformation. I would not recommend that the average DIY or inexperienced person attempt to replace the gas springs. It is a tricky procedure which would result in bodily harm if the compressed spring gets away from you.
Posted by: Marshall on Jan-21-13 10:34 AM (EST)
I would guess that Thule doesn't want any modifications to the mechanism being done by anyone other than Thule, for the exact potential injury and mechanical complication issues you've mentioned. I don't know how much traction your complaint is going to get.
Posted by: old_user on Jan-21-13 12:59 PM (EST)
Yes, that's probably true. But, I did tell them exactly what the problem was and what I intended to do in replacing the gas springs and that I needed to know the exact poundage of the springs in order to do that. They told me 40lbs.
Posted by: suiram on Jan-22-13 9:46 AM (EST)
Not to defend Thule, but 40kg come out at 88lb, which is quite close to the 100lb
Thule customer service problem|
Posted by: old_user on Jan-22-13 10:54 AM (EST)
I think their problem is that they think that since the Hullavator lifts 40 lbs, the gas springs must be rated at 40 lbs. It was the same mistake I initially made. But it could be 40kg.
Posted by: CEWilson on Jan-21-13 11:56 PM (EST)
Instead of spending ~half a K on a hullavator, put that cash into the boat! You can then left your kayak onto the racks and carry it to the water. Neat concept, get a lighter boat.
cost of hullavator|
Posted by: old_user on Jan-22-13 9:28 AM (EST)
I've got plenty of boats, many of which are light, but I also am getting plenty of years, so the Hullavator is more appealing. I have a couple of high vehicles and getting any boats up there, light or heavy is an awkward task. Hence my interest in overpriced accessories.
Another leverage option|
Posted by: Marshall on Jan-22-13 9:54 AM (EST)
You could always use a Kari-Teck Rolling Rail Rack arrangement. It requires a bit of coordination but I carry 3 kayaks on it in Thule Hull-a-Port Pros on my SUV which is way tall.
Kerry, We have two Hullivators and |
Posted by: shirlann on Jan-22-13 7:37 PM (EST)
like you we are getting up there in years, plus I am a shorty. Hubby is 5'8". Love my Hullavator. Wish I'd had one years ago, but glad it isn't the earlier style which had problems with the gas struts.
Reply from Thule|
Posted by: old_user on Jan-23-13 11:51 AM (EST)
I heard back from Thule. They agreed that their tech department had given the 40lb figure and offered to resolve the problem by shipping me new lifting assemblies with struts.