I have debate going. Need a little advice
|
GIjaywhaler |
Posted on 05/17/11 - 1:02 PM
|
Member
Personal Page
Posts: 60
Comments:
1
Joined: 06/17/09
|
Here is the topic.
If you have two Kayaks that are the same lenght and have the same beam and you fill the void or space between the inner and out shell of one kayak with foam. And you leave the other with nothing but sealed in with air. Which one would be able to carry a heavy load. I said the one with the foam core. They guy at work says the boat with just air between the shells. He says the reason is because the foam has weight to it and cant hold as much as the one with just air.
So what say every one on here which kayak would be able to hold more cargo?
Thanks
Jay
|
|
|
|
Swamp |
Posted on 05/17/11 - 1:17 PM
|
Member
Posts: 162
Comments:
0
Joined: 01/28/11
|
The foam would add weight to one boat. The volume would be the same between both boats. The boat with more weight (foam) will displace more and sit lower in the water. It would take less added weight to swamp the foam-filled boat than the air-filled boat.
So the foam filled boat could carry less weight. But in reality, the difference would only be a few pounds.
That is assuming the two boats are exactly the same otherwise.
Edited by Swamp on 05/17/11 - 1:18 PM |
|
|
|
Paulsv |
Posted on 05/17/11 - 1:37 PM
|
Member
Personal Page
Posts: 122
Comments:
0
Joined: 08/27/07
|
If all you are talking about is weight and displacement, the foam boat, being heavier, would carry less weight. In the real world, the boat with the foam core would be much stiffer, because of the shell / foam / shell lamination, and therefore the shells could be made thinner and lighter while retaining the same stiffness. The boat could be made lighter than the one without foam, and it would then carry more weight.
|
|
|
|
Bake |
Posted on 05/17/11 - 2:17 PM
|
Member
Personal Page
Project Albums
Posts: 902
Comments:
8
Joined: 01/30/06
|
I would have to agree that just putting foam in does not equal more buoyancy. I guess I would be stating the oblivious to say if the foam were on the outside of the hull it would displace volume and float higher with more weight.
|
|
|
|
mdpolakow |
Posted on 05/22/11 - 5:46 AM
|
Member
Personal Page
Posts: 9
Comments:
0
Joined: 05/04/11
|
As a Naval Architect I feel somewhat qualified with my answer. The amount of weight that a boat can carry is equal to the mass of the water that it displaces when empty. Adding the foam effectively amounts to cargo and will take away from the total. So the boat filled with air will carry more weight on deck by the weight of the foam added to the hull of the kayak. In the end you could argue that it is just how you loaded the weight.
|
|
|
|
Tom W Clark |
Posted on 05/22/11 - 9:02 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
I am not a Naval Architect, but I did take Physics as a Junior in High school. That makes me equally well qualified to answer this question and I concur with the obvious answers above.
The answer is so obvious I kept waiting for the punch-line; I assumed it was a trick question.
|
|
|
|
jharrell |
Posted on 05/22/11 - 10:01 AM
|
Member
Personal Page
Posts: 77
Comments:
0
Joined: 08/26/09
|
How about this for a punchline:
There is no replacement for displacement?
|
|
|
|
Tom W Clark |
Posted on 05/22/11 - 10:29 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
Hey! That's pretty good.
|
|
|
|
GIjaywhaler |
Posted on 05/23/11 - 4:39 PM
|
Member
Personal Page
Posts: 60
Comments:
1
Joined: 06/17/09
|
Tom W Clark wrote:
I am not a Naval Architect, but I did take Physics as a Junior in High school. That makes me equally well qualified to answer this question and I concur with the obvious answers above.
The answer is so obvious I kept waiting for the punch-line; I assumed it was a trick question.
No there is no punch line. After I mde the thread I should have deleted right away. Because after typing out my first response and then rereading it. I said to myself "self that just doesn't make any sense. Air weighs next to nothing compared to what foam weighs. Of course the boat with air is going to carry more". Then I went back and replayed the conversation my Co-worker and I had. And that is when I found out where we both went off course and how this thread came about. He and I were talking about 2 differnt things. I was talking about a boat that was filled with a closed cell foam could still carry a load even if the hull had a hole in it. While the other air filled boat would then sink do to water now filling the once Air filled boat. And he was talking about a swamped boat and somthing else as well. Once I brought this up to him we both agreed that we had once again started talking about something and then both of us end up talking about something else completely different.
Any way thanks for the replys to this thread.
Jay
|
|
|
|
JohnnyCW |
Posted on 05/23/11 - 5:52 PM
|
Member
Posts: 684
Comments:
0
Joined: 08/16/09
|
As obvious as it may seem to some, it isn't to everyone. I remember a conversation with a college a while back about him wanting his small aluminum jon boat to float a bit higher in the water. He passed an idea by me of adding pourable foam into two large storage spaces under each of the seats.
I think some folks just associate foam with flotation and don't put much thought into it beyond that. The fact the foam itself adds mass just seems to escape consideration sometimes.
|
|
|
|
Binkie |
Posted on 05/23/11 - 8:30 PM
|
Member
Personal Page
Posts: 2012
Comments:
0
Joined: 12/19/05
|
I said the one with the foam core. They guy at work says the boat with just air between the shells. He says the reason is because the foam has weight to it and cant hold as much as the one with just air.
If the guy at work is not your boss today, he will be by next Monday.
|
|
|
|
theo |
Posted on 05/23/11 - 8:37 PM
|
Member
Personal Page
Posts: 252
Comments:
0
Joined: 08/26/08
|
Hmm. Start out talking about the same thing and end up with completely different subjects. Sounds a little like being married!
Edited by theo on 05/23/11 - 8:38 PM
Ted
1985 15' CC, 1994 60 hp Merc (Wednesday built), 5" jack plate |
|
|
|
Wiley64 |
Posted on 05/24/11 - 7:01 AM
|
Member
Posts: 1
Comments:
0
Joined: 07/17/07
|
Depends on the kayak, ocean kayak- yes, non-ocean kayak completely different story. Picture a non-ocean kayak that can take on water if your not wearing the stupid skirt for it. Fill that with foam. Boat A filled with foam, which is simply glorified air that can not be overtaken when the boat is taking on water. Boat B filled with air, begins taking on water. Put a giant weight on both boats. Boat A floats, boat B sinks.
Edited by Wiley64 on 05/24/11 - 7:04 AM |
|
|
|
CES |
Posted on 05/24/11 - 7:17 AM
|
Member
Personal Page
Photo Albums
Project Albums
Posts: 2681
Comments:
7
Joined: 04/27/07
|
I am not a Naval Architect either, however I am a retired US Navy Sailor who's spent many years on board huge metal floating cities which makes me equally well qualified to answer this question and I too agree with the statements above.
With that said, I'd rather be out at sea in a boat that has holes in it that's filled with foam than be out at sea in a boat with holes in it that's not filled foam....
Just sayin'.....lol.
Cliff
1966 13' Sport with a 1993 40hp Yamaha 2 Smoker |
|
|
|
JohnnyCW |
Posted on 05/24/11 - 8:52 AM
|
Member
Posts: 684
Comments:
0
Joined: 08/16/09
|
CES wrote:With that said, I'd rather be out at sea in a boat that has holes in it that's filled with foam than be out at sea in a boat with holes in it that's not filled foam....
I think I know a boat built just like that... lol
|
|
|
|
CES |
Posted on 05/24/11 - 9:09 AM
|
Member
Personal Page
Photo Albums
Project Albums
Posts: 2681
Comments:
7
Joined: 04/27/07
|
JohnnyCW wrote:
CES wrote:
With that said, I'd rather be out at sea in a boat that has holes in it that's filled with foam than be out at sea in a boat with holes in it that's not filled foam....
I think I know a boat built just like that... lol
Yep, we're seeing eye to eye here. Lol.
Cliff
1966 13' Sport with a 1993 40hp Yamaha 2 Smoker |
|
|
|
GIjaywhaler |
Posted on 05/24/11 - 12:31 PM
|
Member
Personal Page
Posts: 60
Comments:
1
Joined: 06/17/09
|
Binkie wrote:
I said the one with the foam core. They guy at work says the boat with just air between the shells. He says the reason is because the foam has weight to it and cant hold as much as the one with just air.
If the guy at work is not your boss today, he will be by next Monday.
Try the other way around... But thanks for playing just the same....
|
|
|
|
duf |
Posted on 05/24/11 - 3:27 PM
|
Member
Personal Page
Photo Albums
Posts: 840
Comments:
9
Joined: 04/22/07
|
Frankly, you guys make my head hurt. Think i'll stick to fixing helicopters..........
Duf
|
|
|
|
CES |
Posted on 05/24/11 - 4:16 PM
|
Member
Personal Page
Photo Albums
Project Albums
Posts: 2681
Comments:
7
Joined: 04/27/07
|
duf wrote:
Frankly, you guys make my head hurt. Think i'll stick to fixing helicopters..........
Duf
Lol, a device that's not supposed to fly but does.
Cliff
1966 13' Sport with a 1993 40hp Yamaha 2 Smoker |
|
|
|
John Fyke |
Posted on 05/24/11 - 6:18 PM
|
Member
Personal Page
Posts: 1307
Comments:
0
Joined: 09/06/06
|
The initial thread sead nothing about holes in the Kayaks but I will agree that no foam will cary more weight.
John Fyke
Re-Fit or Reef It
1979 15' Sport with Super Sport conversion and 70hp mercury. |
|
|