Flying Saucer Build

Outboard designs up to 14'

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miyot
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Location: WV

Re: Flying Saucer Build

Postby miyot » Sun Oct 05, 2014 6:55 pm

vupilot wrote:Pretty amazing that you built this in the amount of time you did, it looks great! I'd love to see some video of it with that new 25 pushing it along when you take it out.


Thanks, Vupilot. It sure doesn't look like the other fellows boats on this site. But the goal was to get it done quick and still have a nice little boat, and I think I accomplished that. I can't wait to see how she performs. If I can figure out how to down load some video, I will. That 4 stroke on her looks like half the boat. I'm confident she will perform nicely. Its a nice design.

Mojo
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Re: Flying Saucer Build

Postby Mojo » Wed Oct 08, 2014 12:46 am

Wow mate! Start to finish in a few months! Also interested to hear how she goes in the water.
Cheers
Mojo

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travis24
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Re: Flying Saucer Build

Postby travis24 » Sat Oct 11, 2014 3:37 am

Impressive ! Way to go on your build. Have fun now and enjoy!! :D

Travis
It's like anything you Build. You have to be Patient.

Measure Twice, cut Once.

Keep em Alive ! Vintage & Antique outboards

www.liquidassetsonline.org

miyot
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Joined: Tue Jul 22, 2014 10:23 pm
Location: WV

Re: Flying Saucer Build

Postby miyot » Sat Oct 11, 2014 2:31 pm

Well here are some performance figures for the first splash. At full throttle we got 27 mph ( my daughter and I). Porpoising started at 26 mph. I may need to re prop, although I don't have a tach. It seemed to need a little more prop. My outboard dealer will run it next week with a tach to see what I'm turning. I believe the porpoising problem is inherent with this hull after reading a lot of other posts on this boat.

I am not going to try a fix for the porpoising as it only does it at full throttle and she runs perfect around 22 - 24 mph. (quite fast enough for me) I am happy with the performance and will only re prop if she is turning over specs. Hard over turns were quite comfortable. She slips quite a bit without a little skeg or keel on, but I like just how she runs. Hard turns didn't bleed off a lot of speed and I liked that. At speed she runs a little bow high, but never felt loose or unstable.

If I shimmed the engine so I could trim it in a little closer to the transom I feel it would bring the bow down a bit and give me a little more speed. I don't feel the performance increase, if any, would be worth the effort. The 4 stroke Merc 25 HP is quite heavy at 180 lbs and trim tabs may help her plane off a little quicker and also bring the bow down a bit with perhaps a gain of 1 or 2 mph. Again I am going to pass on this upgrade as well. I could have just said I'm happy with her performance.
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Mojo
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Re: Flying Saucer Build

Postby Mojo » Sun Oct 12, 2014 3:49 am

Glad to hear it got wet. Congratulations!
I wonder if part of the reason these hulls are porpoising is because we are running more powerful and heavier engines then what was originally designed. I imagine if I was running an old 25hp (which is equivilant power to a modern 20hp) then I would probably only be getting speeds just over 20mph. My Flying Saucer would be stable at these speeds and it sounds like your would be too.

Cheers
Mojo

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vupilot
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Re: Flying Saucer Build

Postby vupilot » Sun Oct 12, 2014 8:27 am

Great pictures! Thanks for the report. It really looks really nice on the water.

miyot
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Location: WV

Re: Flying Saucer Build

Postby miyot » Mon Oct 13, 2014 5:51 am

Well here is another update. I spent 6 hrs running the boat yesterday. Overall, going down current, the boat begins to porpoise around 20 - 21 mph. Going up current the boat begins to porpoise around 19 - 20 mph. Under these speeds the boat performs well. These tests were done with 2 adults on board. If we both moved forward the porpoising lessened.

I believe a lot of the problem is the weight of the engine (25 hp 4 stroke at 180lbs.), as stated by Mojo. I get significant bow rise until the boat comes on plane. Although my battery is up front, I don't have room to put the fuel tank up there. I don't feel adding weight forward (such as sand bags, etc) is the right fix. So I will be adding the smart tabs. As it is now, it takes longer than it should to get on plane and I'm losing about 7 - 10 mph off my top end.

I believe the trim tabs will give me the fix I'm looking for. Quicker to get on plane and perhaps 4 - 5 mph more or a little less for cruising speed. Which now is around 18 mph. I could live with that, but I feel the 180 dollars for the tabs will pay off in the long run. Also at around 14 mph hr the boat wants to drop off plane, I hope the tabs will give me a little bigger planing window. It is a nice little boat and overall I am happy with it.

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vupilot
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Re: Flying Saucer Build

Postby vupilot » Mon Oct 13, 2014 6:22 am

I rode in Ted's Zip with one of the hydrofoils on the outboard. It had a big Honda 4 stroke and the hydrofoil made the boat plane quicker and stay on plane slower as well as a smooth ride at all speeds. I think either would give you the results you are looking for.

miyot
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Re: Flying Saucer Build

Postby miyot » Sun Oct 19, 2014 7:00 pm

Porpoising update: I installed Bennett SLT (self leveling trim tabs). The porpoising has been eliminated. No sign of it at any speed. The boat comes on plane with hardly any noticeable bow rise. Cruise speed went from 18 mph to 20 - 22 mph. Top speed is 27 mph at wide open throttle and no trace of porpoising, even in a swell and heavy chop.

The boat now stays on plane down to about 11 mph or a little less, 3 - 4 mph slower than without the trim tabs. I'm sure now that the porpoising problem was caused by the weight of the modern 4 stroke engine and not a hull problem. For a 12 ft. boat her performance is awesome. Now I'll get my dealer to run her with a tach and see what she is turning. I still suspect she will need to step up to a bigger prop for final tweaking and get some more top end and perhaps a little more cruise speed. I could not be more pleased with the boat. Although I put her together fast, she still turns heads. A wonderful design.
Dave

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Andy Garrett
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Re: Flying Saucer Build

Postby Andy Garrett » Sun Nov 02, 2014 8:54 am

Shocking how fast you completed this. My build was on a geologic time scale by comparison.

Regarding you Bennett SLT trim tabs: I assume you selected the smaller size? My Zip is 14' and that places it right on the line between sizes. I'm wondering if you could help me make a choice based on your experience with the product.

The Zip and FS are the same boat except for length, but I suspect mine is considerably heavier. The variables are too numerous to list, but I just wondered if you could expand on your product evaluation a bit more. I'm sure it would serve other Zip/FS builders as well.

Thanks.
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

miyot
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Joined: Tue Jul 22, 2014 10:23 pm
Location: WV

Re: Flying Saucer Build

Postby miyot » Sun Nov 02, 2014 12:01 pm

Andy, I did get the smaller Bennett tabs. They have three adjustments on them. Three sets of holes on the tabs. The instructions say to initially use the middle holes and try it out. Well I'm a pretty smart guy, so I used the heaviest setting first. This was to much tab or down force, porpoising was eliminated but the boat would not reach optimum speed and the bow remained down or to low. Moving the piston to the middle holes only takes a couple minutes. This did the trick, no porpoising and I think top speed is being reached. This setting, the middle setting, is where I will leave them set.

Now I can't say for sure, but I suspect the small tabs will be ok on the zip. With the tab at the heavy setting, the 25 HP engine would not push fast enough to allow the tabs to come completely horizontal to the waters surface. They remained down enough to cause substantial drag. Hope this helps some, but still not a guarantee you won't need the bigger tabs.


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