Accurate weight for catamaran in CT / RI

[myosys]

Hey cruisers, I'd like to get an accurate weight of my Catana 381 for a repower project. Does anyone have any companies they can recommend for load cells in CT? Later this summer, I also plan to visit RigPro in Portsmouth, so I'd also be haul there.

[grantmc]

Many travel lifts have a weight scale. Call the place you're planning to use and confirm there's does..

[myosys]

Originally Posted by grantmc

Many travel lifts have a weight scale. Call the place you're planning to use and confirm there's does..

Trouble is... accurate. I don't need precision, but accuracy. Lots of these travellifts do pretty poorly with lighter boats, and the travellift handles a 24' beam and hauls tugs, so my recreational cat is a paperweight.

[tkeithlu]

Can you put it on a trailer and take it to a truck scales?

Nahh. It's too wide and has its mast up. Darn

[noelex 77]

If you have an accurate plan of the hull shape, you can measure the freeboard at various locations, which will enable you to calculate the immersed volume. This will reveal the displacement. Archimedes was a clever and obvervant physicist.

It would be a tedious and lengthy calculation to do manually, but should be possible and it is something you can do yourself.

[myosys]

@noelex 77, true true, I was hoping for something less labor intensive given my lack of time (which == money.) As you can see from my profile, I have another sailing cat and small fishing boat to maintain , much less use, lol :crazy_multiple_boat_owner_emoji_needed:

[JPA Cate]

Doesn't what kind of performance you want under power come into this? You can move a big monohull with a 3 hp o/b in light air, no waves. Surely you want something more, but what?

On the other hand, you're not likely to be drag racing with it either.

Was it under powered by your standards with it's original hp? Does it have diesel saildrives? what hp? or if o/bs what hp? Maybe you can work this out from the usage perspective?

Otherwise, bless old Archimedes, and get to work!

Ann

[myosys]

Originally Posted by JPA Cate

Doesn't what kind of performance you want under power come into this? You can move a big monohull with a 3 hp o/b in light air, no waves. Surely you want something more, but what?

On the other hand, you're not likely to be drag racing with it either.

Was it under powered by your standards with it's original hp? Does it have diesel saildrives? what hp? or if o/bs what hp? Maybe you can work this out from the usage perspective?

Otherwise, bless old Archimedes, and get to work!

Ann

hahaha, well, power-wise, there are Volvo MD2030 w/ saildrives in there now. Getting mighty iffy $ to maintain, so it's time to stop throwing good money in after bad.

These engines, with the Volvo 3 blade folders, were adequate on the way up from FL back to CT; we did hit weather. I'm going for reliability and not being used as a cash mule by Volvo, so I contacted Stan at Beta Marine. Their records indicate that they've repowered my model with Beta 25. The original spec from Christophe Barreau (designer) was 18HP, so the existing MD2030 is pushing it.

The purpose of an accurate weight is to know where I land once I finish stripping the boat, and then to take care when adding weight back to the boat. I also own a high performance cat (this weighs 3800 lbs) and know what happens when you're overloaded (although, the hull design on that boat is a lot more sensitive than a cruising cat.)

[myosys]

Originally Posted by tkeithlu

Can you put it on a trailer and take it to a truck scales?

Nahh. It's too wide and has its mast up. Darn

Now you've got me thinking, maybe I can find portable wheel scales for rent.

[CarlF]

So is the engine dealer saying that he'll recommend a different engine or transmission over a small difference like 500lbs? Seems hard to believe.

The number is likely to be pretty close to published displacement (about 12,300lb - assuming that is light ship) plus 2000 lbs for minimal cruising gear and 1/2 tanks. The fuel and water tanks alone can change the weight by over 1000lbs.

Another tack is to have it hauled by 2 travelifts. If the load cells are within 5% just average them and call it done. If they are way off, use the one that seems more right based on the published displacement.

The Perfect is the Enemy of the Good

[BillKny]

My experience with having the same boat hauled by different travel lifts is that the "weight" reported by the hydraulic pressure gauges is no better than +/-15%. All they are there for is to let the operator avoid overload.

One resource for locating a strain gauge equipped lift is a local yacht club with a very serious big boat racing fleet. Some of the class rules require an annual weigh-in.

But I agree, for sizing an engine... trying to sharpen the pencil as much as you are seems pointless.

[myosys]

Thanks for the advice. I'll report back. Probably will go find a place that rents portable wheel scales.

[Jahwork]

Greetings,

A few years back when I ran a travel lift at a local boat yard we had an accident investigation team that wanted the precise weight of a vessel which had been involved in a fatality collision. They had the commercial vehicle enforcement division of our local state police put down their portable wheel scales, the ones they use to weigh semi trucks alongside the road when not near a weigh station. They had me drive the travel lift onto the four scales both empty and with the boat in the slings. I think they then employed some highly secretive super advanced mathematical formula to subtract the lesser value from the larger and voila, they now had the vessel weight with certified scales to within a pound.

Now where and how to find or rent similar scales is the part of the plan I am unable to assist you with.

Safe Journeys,
~Jake

[Factor]

What we do for OMR rating, just get 3 load cells

[Pandor]

Originally Posted by Jahwork

Greetings,

A few years back when I ran a travel lift at a local boat yard we had an accident investigation team that wanted the precise weight of a vessel which had been involved in a fatality collision. They had the commercial vehicle enforcement division of our local state police put down their portable wheel scales, the ones they use to weigh semi trucks alongside the road when not near a weigh station. They had me drive the travel lift onto the four scales both empty and with the boat in the slings. I think they then employed some highly secretive super advanced mathematical formula to subtract the lesser value from the larger and voila, they now had the vessel weight with certified scales to within a pound.

Now where and how to find or rent similar scales is the part of the plan I am unable to assist you with.

Safe Journeys,
~Jake

So were you able to compare the results with the guage on your lift to determine how accurate the lift was?