Accurate weight for catamaran in CT / RI

[django37]

Had my boat weighed 3 times using scale meant for weighing windturbine blades. Accurate to +/- 10 kg at weight less than 10,000 kg. Each year less than 20 kg diff.

[Sand crab]

They rent load cells btw. Here's one:
https://www.hydrowates.com/load-cell...equipment.html

[Captain Bill]

I read somewhere that someone tested several travel lifts for weight accuracy and that they averaged 50% error. I've had mine weighed twice on travel lifts. Lightship weight from the factory is 14,500 lb. Adding all the stuff on board Including a 450 lb genset, fuel, water cruising stuff I figured I have between 4000 and 5000 lb of stuff on board. I got one reading of 19,400 and another at 29,900 with no significant change in load. The lower reading is probably more accurate as it is pretty close to a rough approximation that I made from displacement. My rough approximation definitely was an over estimate based on rectangular approximations of various sections of the hull's displacements, which came in at about 22,000 lb, but did not account well for rounded sections of the hull. My guess is that it weighs about 20,000 lb fully loaded for cruising so one travel lift was probably close to accurate and the other off by about 50%.

[Jahwork]

Pandor,

I should have mentioned earlier that the old 40-ton travel lift I ran did not have built in weight sensing or measuring capabilities. The old school method was we used the “as built” weight ratings to determine whether or not we would lift a boat. If we were concerned, the old school method was......and I know many will not find this acceptable.....we would hoist the boat about two feet off the water, wait for about 20 minutes and if it hadn’t fallen back in the water by then we hoisted her out. Probably isn’t what would be acceptable today but back in the day that was how it was done. Never dropped a boat by the way. Where I own a slip and keep my boat today is next door to a mega yacht manufacturing and maintenance facility here in Seattle. Here is an example of what their massive 440 ton travel lift, with all the fancy technology, did to a 22+ million dollar yacht during launching last year after it had been in the shed for 10 months undergoing a complete refit. It has been back in the shed now for the last 6-10 months being rebuilt again after flooding a large portion of the vessel and damaging the running gear after being dropped onto the river bed. It was quite a show to see, hear and feel as the massive wave crashed through our marina when the boat fell. I am amazed that the forward straps didn’t fail after the stern crashed into the water.

Safe Journeys,
~Jake

[MIRELOS]

Bridgeport Boat Works are well equipped and haul lots of multis of every size

[myosys]

Originally Posted by MIRELOS

Bridgeport Boat Works are well equipped and haul lots of multis of every size

Yeah, they're not far from me. In my experience, most travellift scales are pretty "meh" on the accuracy. If I remember correctly, Bridgeport Boatworks is the old Derecktor's site. I see a lot of cats hauled there now when I drive by on I-95.

Totally off topic, but there are more yards capable of hauling cats now.

New England Boatworks (now Safe Harbor?) in Portsmouth was working on carving in a new travellift basin a few years back and they just finished last summer. They can haul a 34' beam. I'm going to head there this summer for a visit with RigPro since I need a carbon mast specialist for service.

And the original Derecktor's yard in Mamaroneck has always had a giant crane that can haul cats of any width. It's just a small yard and fairly pricey.

But I digress... thanks for the constructive advice.

[myosys]

Originally Posted by Jahwork

Here is an example of what their massive 440 ton travel lift, with all the fancy technology, did to a 22+ million dollar yacht during launching last year after it had been in the shed for 10 months undergoing a complete refit.

Wow... excessive hubris due to travellift size? perhaps, lack of maintenance "who checked the shackles last" or "gee that strap looks pretty fuzzy"

I remember watching video of the failed launching of "Bäden" in Anacortes, WA. "oo.. oooo.. oooo nooooooo"

[purvisgs]

I would call around to cranes and see what equipment they have - depending on your haulout plans & duration etc - that could (perhaps) offset the higher haulout cost vs travel lift by allowing you to haulout and pay for a (potentially more affordable) storage or work space in a location that might not otherwise be accessible to a multihull.