Thought I'd start a new thread...Kevin Turner questionWater is retentive and clings to smooth, curved surfaces. I’ve found hulls with glue on UHMW had a difficult time breaking the waters grip and were slow to plane. A couple of quick port/star turns would shear the waters grip and allow the bow to rise. Once free, it was like a different boat.In an earlier post you said,
"...did one hull have full or partial UHMW (B/C UHMW will suck ya to the water until you get the nose lifted),..."
I am wondering how you got that info? The friction co-efficient of UHMW, dry or wet, is substantially less than aluminum, and it is 99% buoyant.
UHMW added to an existing hull could change hull dynamics. The longitudinals/stringers and lifting strakes might not protrude as much therefore being less effective in providing lift. Keep in mind that UHMW weighs in at 2.6 lbs/sq ft at 1/2" thick. A boat with UHMW on the bottom measuring 6'x18" at 1/2" thick adds 280 lbs to the deadweight.
I am always looking at ways to use UHMW. Any feedback is appreciated.
A simple test: Gently dangle a kitchen spoon between your fingers. Now, allow the dangled spoon to barely contact a stream of flowing water (from the sink). The water will wrap itself around the spoon and suck it deeper into the flow.
The same thing happens with differing hull designs. With no strakes to shear the waters grip, a long sweeping bow with UHMW will stay firmly planted to the water surface until the magical point of release. Once released, she’ll perform much better for ya.
I share your puzzlement...Still not with you Kevin
If you have 2 identical hulls, (same weight, width, length, deadrise, longitudinal, lifitng strakes, etc. even the same fat guy driving) one aluminum, one UHMW, the UHMW wins getting out of the water.
If you are comparing a hull that has been modified, then you no longer have a valid comparison. You would have to figure out the same percentage of protrusion that exists on the original boat and make the modifications.
We know that a boat in a light chop gets up quicker than off of glassy water. I get the retention part, but all thing being identical (which I don't see how you could pull it off) you have to also measure the drag on the aluminum over the surface area.
Therefore I do not see how the UHMWPE is the issue here.
Of the UHMW hulls I've built or taken part in building, UHMW has had a adverse handling effect on every one.
As stated above, if you don't shear the waters grip, the UHMW hull stays sucked to the water.
In my 240 Sport Jet powered UHMW hull tests, moving 200lbs of sand bags from the stern to the bow, slowed the boat 8 MPH. Using the same hull design, w/o UHMW, moving the weight forward had little effect on speed.
Another UHMW negative was handling. The UHMW only added 220 lbs to the hull, but it was sluggish & slippery in turns.