Mono Strake questions

[befu]

OK, I have had my 24" mono running a few times, but I never put strakes on the hull. Has a built spray rail, but the strakes are to be added. I have several strakes now that need to be glued onto the hull, in the pictures below they are just laying there. Still need to have the edges sanded as they are raw bondo fresh out of the mold.

My own 24" mono, hardware from a 25" prince mono hull, Turnigy 3650-2300 motor, 35 amp HKSS speed control, and two 3s-1800 packs in parrallel. 28mm plastic prop from OSE, average amp draw is around 22 amps (5 minutes on one pack). Motor is rated at 400 watts, which is 36 amps on 3s. (need an eagle tree from Santa!) RTR weight is right at 2.5 pounds with both batteries.

It seems to run pretty wet right now, think the batteries need to move back, but the strakes will also help to dry the hull up some. It is like driving a drifter as it really slides thorught the corners. The second battery helps as it adds some weight. Haven't tried a turn fin yet, will add that later.

So, where should I put the strakes? I was looking at two per side, evenly spaced. The outer one starting at the transom, the inner one starting about 3 inches forward of the transom. Anyone have any input? Three strakes, other crazy ideas?

You know, it was a really pretty looking hull with the kevlar and carbon mat, but I put some spray foam inside it and now the bow area looks funky. I constantly amaze myself with my own stupidity

[befu]

bump

bump back up. Just wondering if any of the experienced racers/designers have any input on this before I take the plunge.

Thank you,

Brian

[Darin Jordan]

I can give you some limited input...

Wherever you put strakes, you are adding lift...

When you run them all the way back, you add lift ALL the way back...

On a FAST mono, like a P-Mono, or frankly just about any mono other than an N1 boat, I wouldn't run the strakes all the way to the back. To be stable, you NEED to keep part of the hull in contact with the water.

ON that hull you have pictured, I'd go with two strakes per side... I'd stop them well short of the transom... I don't have exact dimensions handy, but I'd perhaps stop the outters about 5" from the transom, and the lower ones 7" from the transom.

Another place strakes help is in the turns, but NOT for "bite"... they actually help shed water from the hull... The examples you show stop WAY too far short of the bow... I'd run them ALL the way up... They will help to LIFT the front of the hull in the turns and keep the boat from sucking down. The original Dark Horse Monos have this issue, and since I've revised the strakes on mine, it handles AWESOME... I moved them forward and it really helped.

You'll also want to add a "spray rail" along the chine on both sides. Basically a strake along the chine. This deflects water in the turns and keeps it from climbing up the side of the hull when turning.

I'll try to dig out some pictures to show you what I mean, but basically, what I'd do is copy what they did on the 25.5" Delta Force Mono...

[befu]

Thank you

Cool, thank you for the input.

The sides do have spray rails. They are only about 1/4" wide and are flat. I originally made this hull for some guys who were running FE back in the 90's so I made sure the spray rails were zero degrees per IMPBA rules. I will post a pic of a white hull, I think they are more visible on those.

I left the inner strakes off so they could put thier own on depending on how the boat was set up. Only ever saw one run, that was a 6 cell boat on an Astro 05. Also saw one setup with a 05 can using a huey gear drive.

Well, I can definately put them all the way to the front. I have enough pieces made up, just glue them on and blend the seams!

Thank you again sir!

Brian

[befu]

spray rails

Attached is a picture of the same hull in white gelcoat, as the spray rails show up a bit better

[befu]

Added strakes

Alright, couple of pics below of this thing. Need better video source, please make a recommendation.



I do like running this. It seems fast to me, and all on 22 amps average. I could definately prop it up some more with how much the sc and motor are rated for.

Brian

[befu]

Hatch options

OK, this is a gelcoated fiberglass hull, but it is the same thing as the boat above. I am looking at a couple of hatches I could make for it. I pulled one off the plug for my 18" mystic canopy and also one of the crackerbox hatches.

The mystic I do not think will work as the contour is all wrong. Also doesn't look right. The crackerbox didn't look right either until I turned it around. If I cut the hatch in half so the engine is in the back and the two guys are facing forward, but in front of the engine, I think it looks alright. Kinda like a jet boat or v-drive boat.

Brian

[befu]

eagle tree.

Ran this boat with the eagle tree setup. Ran in a larger lake and very windy. Had some 2" to 4" chop. I would accelerate great and start skimming the tops of the waves and then blow over or stuff really hard! Top speed with the GPS was 34mph. Top amps was 53 amps which surprised me it was that high. Now I have to figure out the rpm because it must be the type of motor or poles, becuase it was saying 62,010 rpm. It is a 2300 kv Turnigy on 11.2 volts which gives 25,760 rpm peak. Now, that is when the prop left the water, it is neat to be able to see the spikes of the rpm with the drop in amps vs the speed. So maybe it was 1/3 that, or about 21000 rpm? Cool gadgets.

It would run about 11 amps going at 16 mph while heading into the wind to set up a run along the shore. Wind was blowing towards the shore, so it made retrieval easy. Then when I opened it up, amps jumped to 44, then 10, then 42, then 11 as speed increased from 18 to 34. As it went faster, the peak amps went lower until it blew over. Neat to see, have to run it on calm water soon to see what it does.

Anyways, I know the boat runs at least mid 30's and has more in it. I will be interested to see what the amps do on calm water as they average draw is not that high.

maybe I will get out this week and try it out at the standard pond and get some good data.

Brian