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| Hydrofoil https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=2305 |
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| Author: | BEEZY [ Wed Aug 06, 2008 9:14 pm ] |
| Post subject: | Hydrofoil |
Just wondering who has tried a hydrofoil on their boat. Not sure which one would be best. My boat is a 1998 245 Sundowner with 5.7 and duoprop. I have F4 props. Thanks in advance. |
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| Author: | St. Louis Dave [ Thu Aug 07, 2008 11:52 am ] |
| Post subject: | Re: Hydrofoil |
I had one on my 21 foot cuddy. Made a nice difference in holeshot and I was able to maintain a plane at lower speeds. It's worth the $75 IMO. |
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| Author: | M3eater [ Thu Aug 07, 2008 2:03 pm ] |
| Post subject: | Re: Hydrofoil |
Beezy ...... Do you have the 280hp (GS-i) Volvo-DP or the 250HP (GS)? The 280hp GSi should have F6 props. Mine had these and there was plenty of power. Cruise of 2500 to 3000 rpm resulted in 25 to 30 mph ... very fuel efficient too. The 250hp GS would have had F5 props. Your F4 set (which is what our 268V with the 280hp GSi has) is likely spinning the engine too high. An F4 set on a 280hp (in the 245 Sundowner), would be WAY to little prop. We never had a need for thinking about adding a 'foil to the 245. |
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| Author: | BEEZY [ Thu Aug 07, 2008 5:39 pm ] |
| Post subject: | Re: Hydrofoil |
It has an OMC motor I'm not sure what the horsepower rating is. It definitely isn't too small of a prop. It bogs off the line and I've had it (according to the speedometer on the boat) at 47 mph running at about 4400 RPM. I'm the second owner and I'm pretty sure the previous owner put a cam in it. There was paperwork about a cam and it sounds like it lopes pretty good. |
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| Author: | ht32bsx115 [ Sun Aug 10, 2008 1:34 pm ] |
| Post subject: | Re: Hydrofoil |
Howdy, Are you saying that at WOT it turns 47mph at 4400 rpm? If so it "sounds" a bit over-propped. Most 5.7 engines want to turn upwards of 4800-5000 rpm at full throttle..... propping it so it only turns 4400 at WOT would cause it to be a little slow out of the hole... (F4's wouldn't be over propped IMHO) Now having said that, unless you verify your speedometer (with GPS or other known speedometer) and your tach (some tachometers can be as much as 500 rpm off at the high end) you're wasting your time trying to fix anything. (I'm assuming there's nothing else wrong with the engine timing/compression/carb or EFI/plugs/etc) EDIT: Ok...I did a little searching around on Doug Russells site......They don't post parts for an OMC later than 96. You said it was an OMC 5.7L V-8? (It may be a left over 96 model).......Is it TBI or carb? If someone put a "trick" cam in it (and it's TBI) there would have been no way to reprogram the fuel injection. If it's a carb and it's original) is it a 2bbl? Oh by the way, I think a hydrofoil would be a waste of money on any dual-prop boat. Hole-shot is usually not as much of a problem when you have have reduced prop-slip from a dual prop set up. (My hole shot was terrible with the original 460 King Cobra even when it was new!!....now I FLY out of the hole more than twice as fast with the Bravo III and the same HP) Regards, |
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| Author: | BEEZY [ Mon Aug 11, 2008 8:52 am ] |
| Post subject: | Re: Hydrofoil |
Yes, that is at WOT. As far as other problems, Yes. It is also running hot after letting off of the throttle. I replaced the thermostat and the impeller, the circulating pump appears to be fine, the manifolds and risers are new. I am now thinking it may be a head gasket allowing exhaust gasses to get into the circulating pump which would reduce the efficiency of the pump and also cause power loss. |
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| Author: | Cap'n Morgan [ Mon Aug 11, 2008 10:58 am ] |
| Post subject: | Re: Hydrofoil |
Do a compression check a.s.a.p. That will confirm if you have a head gasket issue. Believe me, you don't want to use the boat if that is the case. Until it is repaired. Also, the hydrofoils can cause undue stress on the lower unit at speed. They do help with holeshot, but a correctly set up 245 with DP, should have no problems getting out of the hole. |
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