Kal-P-Dal wrote:
pmmpete wrote:
Kal-P-Dal wrote:
I have participated in some races (with my Hobie Adventure) and for me there are some limits I can't pass. Maximum speed for a 10 km distance (about 6,2 miles) I can hold is 5,7 miles/hour (9,2 km/h). If I try to go harder my energy drains out fast. For distance between 40-50 km (about 25-30 miles), I can hold an average speed about 7,2-8 km/h (4,5-5 miles/hour).
Those are impressive average speeds, particularly over those distances. Have you pedaled a 13" Revolution, and if so, what do you think is the difference in speed between it and your Adventure?
Those figures relates to my BEST performance. On a race you allways perform a little better than you actually are.
I have no experience of the Revo 13. I will pass the question on to Roadrunner. He knows the diff between the Revo 13 and the Adventure.
The short answer is about .3 MPH faster for the Adventure in the low to mid 5 MPH range.
The "almost as short" answer is more at higher power (higher speeds) and/or more active wind and chop; less for lower power levels. Reasons for this are
1) Adventure design has a lower profile (wind) and can punch through chop more efficiently than the Revo 13.
2) as speeds slow, they get away from "hull speed" limitations; around 4 MPH and lower, most of the Hobie Mirage Drive boats are fairly comparable in speed vs. effort regardless of length. On the other end of the spectrum my best 1 hour "fast cruise" speed with the Adventure is about .5 MPH faster than the Revo 13.
The long answer is complex. Bob mentioned some parameters. From my point of view, actual speed depends on power and hull combinations as follows:
Power: There are 2 issues -- the Drive and the driver.
Drive performance has lots to do with speed. Having Turbos alone is huge! Having the Drive lubed, adjusted (including fin settings) makes a big difference. Excess friction and sub-optimal settings rob you of potential speed.
The driver has to do with leg power, seating position (specifically leg length), pedal position, and to a lesser extent, stroke efficiency. Practice makes for improvement.
Hull:Biggest determinants are length, width and design (hull shape, rocker, etc). Weight is secondary. Every boat has a "hull speed" (don't bother with the formulas -- none of them works for all). I think in terms of zones -- a short zone hull speed (very difficult to exceed) and long zone hull speed (more forgiving and elastic so to speak). Outback is a good example of the former and Adventure is an example of the later.
That said, results will vary from person to person. For me, here are the
average differences with Turbofins:
1. Tandem Adventure (18.5' x 30") dual -- fastest (and benchmark)
2. Adventure (Revolution 16) (16' x 28") -- -.2 MPH
3. Tandem Adventure (18,5' x 30") solo front seat -- -.4
4. Oasis dual (14.5' x 33") -- -.5
4. (tie) Revolution 13 (13.5' x 29") -- -.5
6. Oasis (14,5' x 33") solo front seat -- -.6
7. Outback (12' x 33") -- -.8
8. Revolution 11 (11,5' x 29")-- -.85
9. Outfitter dual (12.5' x 34") -- -.9
9. (tie) Pro Angler 14 (13.5' x 38") -- -.9
10. Sport (9.5' x 30") -- -.11 MPH
As you can see above, length doesn't tell the whole story. You can see the effects of power (dual vs. solo) and width as well.
Tip: you can increase boat speed as you approach hull speed by adding weight to the bow (single seat boats). Why? When hydrodynamic lift raises the bow, the LWL (effective boat length) shortens, limiting speed; bow weight restores it. Usually good for about .1 MPH in many applications. Weight varies according to boat and speed. I use 5# on the Adventure, 10# (dumbbells) on the Revo 11. A friend uses about 7# (padded rock) on the Adventure and always beats me! Keeping your boat on its lines at your cruise speed is the goal -- whatever weight it takes to accomplish that.
PS. Bob, nice speed video!
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