Speed on the Water
Active member
Big news from the most high-powered class in offshore powerboat racing, https://speedonthewater.com/in-the-...ass-unified-to-decrease-power-for-2019-season.
Headlines
Offshore Racing’s Unlimited Class Unified To Decrease Power For 2019 Season
- Thread starter Speed on the Water
- Start date
Ratickle
Founding Member / Super Moderator
I can't believe it will slow them down much though. A 388 Skater pleasure runs 170 (171 actual) with 1100's. I'm assuming a 40 Skater would run almost the same speed based on the competitive nature of both 40' WHM Skaters with the 388 boats.
The canopy improvement to speed should offset any other speed loses associated with a 40 versus the 388.
The canopy improvement to speed should offset any other speed loses associated with a 40 versus the 388.
Ratickle
Founding Member / Super Moderator
Correct, but if they reduce the power in the big cats, a 40' Skater fits in the class. And the original WHM used to be an incredible boat with the bigger motors, ask Jay and Billy. I think that boat, with 1100's, would clean up on the bigger boats with the same power. I'm saying it would run as fast as they do now with 1650's.....
Ratickle
Founding Member / Super Moderator
Absolutely, they need to make the canopy rules have minimum compression and yield requirements. We saw it just recently in the difference between the flips of Beckley's Skater outboard and Nick's Wright outboard. They both flipped in St Clair at about the same speed, just a year or two apart. Beckley didn't even get wet, opening the bottom hatch and climbing out to the recue boat (Balsa Cored Canopy). Nick's canopy imploded and instantly filled the boat with water (Foam Cored Canopy). Difference between end-grain balsa and lightweight foam.
"Shear Strength: The shear strength of most PVC foams is around 40-60 psi; some are much lower. Balsa is 400 psi." http://www.yachtsurvey.com/core_materials.htm
"The fact is that foam cored laminates are extremely vulnerable to impact damage, and can be highly prone to core separation. Our examination of balsa cores revealed that they, too, fared much better than foam cores. The advantage of balsa is that it has both superior bonding strength and superior shear strength. Whereas foam is very weak against inter- laminar shearing forces, balsa is quite strong. This is easy to understand because we all understand how wood is weak with the grain, but very strong against the grain.
We have all heard the hype that foam cored panels are stronger than solid laminates. What you may not have heard is that cored panels are only stronger if they are flat! Curved cored panels are decidedly weaker than solid glass panels, particularly when compressive loads are applied in shear mode. Most foam cored panels take very poorly to bending. The "S" shaped reverse curves of the typical sailboat hull is a case in point, and accounts for why so many failures occur in sailboats. Here we see that the shape of the panel has everything to do with the performance of cores.
The effect of stress and compression loading on foam cored panel. Bending causes inner and outer skins to creep at different rates due to the difference in the radius, causing the core to shear or separate.
To understand what happens to curved panels, imagine an "S" shaped panel like a sail boat hull section. Now, apply a compressive load on the ends as shown opposite. What happens? Well, the inner and outer laminates bend and creep at different rates, owing to the fact that they have a different radius. This causes a very unexpected shearing force that shears the very weak foam. This, in a nutshell, demonstrates why so many foam core failures occur on curved surfaces as compared to flat panels. The shear strength of the foam is simply inadequate to resist these forces." http://www.yachtsurvey.com/HiTech.htm
Graphs of shear and compressive strengths of foam core materials versus balsa core materials: https://www.boatdesign.net/articles/foam-core-properties/index.htm
john acosta
Member
Its simple .
750 cat class period.ok ?
there would be a huge field.
Lose the limited unlimited less hp.boats entirely.
those are for bragging rights .not true competition .
sorry but im right no sense telling me im not
750 cat class period.ok ?
there would be a huge field.
Lose the limited unlimited less hp.boats entirely.
those are for bragging rights .not true competition .
sorry but im right no sense telling me im not
Ratickle
Founding Member / Super Moderator
Of course we all know there are no curved surfaces on a race boat......
The effect of stress and compression loading on foam cored panel. Bending causes inner and outer skins to creep at different rates due to the difference in the radius, causing the core to shear or separate.
To understand what happens to curved panels, imagine an "S" shaped panel like a sail boat hull section. Now, apply a compressive load on the ends as shown opposite. What happens? Well, the inner and outer laminates bend and creep at different rates, owing to the fact that they have a different radius. This causes a very unexpected shearing force that shears the very weak foam. This, in a nutshell, demonstrates why so many foam core failures occur on curved surfaces as compared to flat panels. The shear strength of the foam is simply inadequate to resist these forces."
The effect of stress and compression loading on foam cored panel. Bending causes inner and outer skins to creep at different rates due to the difference in the radius, causing the core to shear or separate.
To understand what happens to curved panels, imagine an "S" shaped panel like a sail boat hull section. Now, apply a compressive load on the ends as shown opposite. What happens? Well, the inner and outer laminates bend and creep at different rates, owing to the fact that they have a different radius. This causes a very unexpected shearing force that shears the very weak foam. This, in a nutshell, demonstrates why so many foam core failures occur on curved surfaces as compared to flat panels. The shear strength of the foam is simply inadequate to resist these forces."
phragle
Charter Member
thought long and hard about that stuff when I beefed up the bottom of the avanti. I had 3/4 coosa avail, but what I did was grind the gel out of the bilge, laid down 3 layers of 1708 with vinylester, then added 4 small stringers and capped it with 3 more interlocking lavers of 1708. So in essence I added 9 more layers of glass.
phragle
Charter Member
thought long and hard about that stuff when I beefed up the bottom of the avanti. I had 3/4 coosa avail, but what I did was grind the gel out of the bilge, laid down 3 layers of 1708 with vinylester, then added 4 small stringers and capped it with 3 more interlocking lavers of 1708. So in essence I added 9 more layers of glass. since the motor is out I will try and get some piks this weekend.
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