Jim, consider this: water weighs about 64 pounds per cubic foot. If a 6400 lb boat sits in the water, it really sits ON the water for the most part; only 100 cubic feet of it sit IN the water. If you add 64 more pounds to the boat, it will displace 101 cubic feet instead, and sit a little lower-but depending on how the boat's built, either a little or a lot of it will still be floating above the surface. All the boat's going to do is displace, or push out of the way, enough water to make up for the boat's weight.
When you move from salt water to fresh, you'll float a little deeper because the fresh water doesn't weigh as much and you have to push more of it out of the way to make up for your boat's weight. Dave Shaddock From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Bernstorf Sent: Wednesday, August 13, 2008 10:32 PM To: [email protected] Subject: RE: catalina27-talk: Hull speed Chris, I understand the definition of displacement. The logic of that though is that if the 6000lb boat displaces 6000 lbs of water then it theoretically would be sitting with the water at the gunnels of the boat and adding another pound would push the boat under water and sink it. I sat back and observed another discussion group arguing over this point and never did read much of anything that I could buy. I don't want to start that same argument here but I just don't think that displacement can be the same as weight or there wouldn't be any buoyancy left: it would be floating dead even with the surface of the water. Do the boat manufacturers actually mean that displacement equals weight? If they do I will sit down and shut up but it just doesn't seem exactly logical based on my understanding of the general definition of displacement in a scientific sense. On the other hand, they never list boat weight other than weight of the ballast.only displacement. Jim _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, August 13, 2008 5:14 PM To: [email protected] Subject: Re: catalina27-talk: Hull speed Jim, 'displacement' is the weight of water that the boat displaces - it's the same as weight. Chris Sent from my Verizon Wireless BlackBerry _____ From: "Jim Bernstorf" <[EMAIL PROTECTED]> Date: Wed, 13 Aug 2008 17:06:02 -0500 To: <[email protected]> Subject: RE: catalina27-talk: Hull speed So is there any relation between displacement and weight? I have wondered what the approximate weight of the C27 but have not seen that number listed anywhere: just displacement. That becomes relevant when trying to acquire/rent/beg/borrow/steal a trailer to put the boat on and drag it to my house to work on such things as repacking the packing bushing over the winter. Jim B _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Sailor Chef Sent: Wednesday, August 13, 2008 8:46 AM To: [email protected] Subject: Re: catalina27-talk: Hull speed Getting the "real" weight is easily done but not cheap. Here are 3 ways: 1. You can rent a certified scale and have your boat yard hoist you out with the scale. Best done with a "single point" lifting system. If you are in or near a major metro area just look up "scales" in the phone book and find a rental. 2. Another way is to have your boat measured for the IRC handicap racing rule, a weight cert comes with it. 3. You can also have the boat pulled, put on a trailer and bring it to your local truck stop and weight your "rig" with and without the boat, then pull out the old abacus. It's gonna run you a few hundred bucks at the least but the cheapest is probably the first. If knowing the "real" weight is that important. Mark, Gratis (6115) Want to keep your WHOLE PAYCHECK? PLEASE VISIT http://www.fairtax.org ----- Original Message ----- From: Joe McCary <mailto:[EMAIL PROTECTED]> To: [email protected] Sent: Wednesday, August 13, 2008 7:17 AM Subject: RE: catalina27-talk: Hull speed Any idea just how we get an actual boat's real weight? My bathroom scale barely reads my weight. Joe McCary Aeolus II, West River, MD [EMAIL PROTECTED] On Behalf Of Phil A Of course no one should be using an assumed factory weight but get a real weight. _____ Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.524 / Virus Database: 270.5.10/1587 - Release Date: 8/2/2008 5:30 PM
