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Bunk trailer needed with lifting strakes?

Probably should have gotten the sealed strakes but it's toooooo late now. it's being built either Thursday or Friday. At least I got them on the order and that means I'll benefit more than if I hadn't been able to get them added. 650 Lbs of added weight doesn't make sense IMO. That's about 80 gallons of water or 40 gallons a side. Visualize twenty, 1 gallon milk jugs on both sides of each pontoon? just thinking.

Dan
 
I'm still having a hard time wrapping my mind around Dans concept. with unsealed the water does get in the strake, but as it is at water level I dont't see it as dead weight but more of a resistance issue. Once the bow starts to raise the water will naturally flor right out the rear cut out. Don't panic for not getting sealed.
 
I doubt any water comes out for the first 5 seconds or so while the strakes are still completely under water. That's all I'm talking about. Yes, then they drain out when air can get in.

Plus the added buoyancy. Just saying for $200 there are some benefits...

I used 6 inch strakes times six strakes (that many are on my boat) times 15 feet each on average. That's 90 linear feet of strakes. Then I converted cubic feet to gallons, then multiply by the weight per gallon of water.
 
I went to sealed strakes for two reasons.

Invasive species
Keeping clean.

One thing I didn't think of much (didn't seem to be that large of impact on the surface) is additional buoyancy as pointed out by Kaydano. I was surprised by his number that was likely just a quick back of envelope calc, so I thought I'd do my own.

Check my math and assumptions.

Assume 6"x6" strake 15' long. Area of triangle = 1/2 BxH = .5 x .5' x .33' (assuming 4" right angle leg or height) = 0.08 sq-ft triangle * 15' = 1.25 cu-ft.

There are 7.5 gal per cu-ft = 1.25*7.5 = 9.4 gal of water (8.3 lbs per gal) displaced per strake = 78lb per strake.

My boat has 4 strakes. This = 312lbs of additional buoyancy for sealed strakes on an ESP boat. Holy crap...never thought of it. If unsealed and water can't escape quickly, it could be considered a 312lb drag.

6 strakes adds an additional 156lbs of buoyancy or potential drag (78x2) = 468 lbs. More holy crap.

I've seen unsealed strakes where they are completely open on the end and others that have a hole (1-2" diameter). I think the hole is a bad idea. Just leave it open to get rid of the water as quickly as possible. Of course you also have leak paths along the toon.

Is it spring yet?
 
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I would have happily paid for sealed strakes if I'd had the choice. More flotation is great, but invasive species alone is worth it out here. 
 
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Everyone is talking about it. Would it take that much to seal them up? Just curious. Worst case shove a couple cans of play dough in the end. Mine are sealed, don't know what unsealed look like.
 
I think you'd have to seal the end and the entire length of the seams. I believe they are just welded on in spots. 
 
My position has been that there is no down side to sealed strakes, unless the cost of $300 is problematic. No trying to clean them inside. No invasive critters. Better planning and buoyancy. Less drag upon acceleration. Better handling in the ESP package. I am sure I am forgetting a few things.


Cheers, Steve
 
fasmnstealth I asked my 6th grader to check your math.  She said it checks out ok and you would get a :) on the top of your paper.  She did say however that that math was "so 5th grade". 

She might not have been impressed but I was!
 
Swabber said:
fasmnstealth I asked my 6th grader to check your math.  She said it checks out ok and you would get a :) on the top of your paper.  She did say however that that math was "so 5th grade". 

She might not have been impressed but I was!
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 LOL..

Funny how I had to do it a couple times because I couldn't believe how much of an impact it was.  It adds up fast!   It certainly puts into perspective the huge impact of the twin ellipticals or any of the 3rd toon options on buoyancy.
 
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Thanks for correcting my math. I did the calc while lying in bed and rounded numbers so I could do it in my head. I was off...

I don't know if you could seal them. One small pin hole in the caulk or whatever you used and they'd fill with water slowly over night or while anchored in a cove and it would take forever to come back out and you'd be dragging that weight with you all day long.

Better to fill the stakes with foam than seal them... How many cans of Great Stuff would you need??? Get out the sixth grader....
 
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So my sps with sealed trakes is one bad boyant mother.....Maybe Bennington will up my capacity plate....
 
I would say my strakes have 6 inch equilateral triangle cross sections. The performance foils on the SPS and ESP appear to be a lot narrower. They might only be one third the volume just by looking at the photos of them.
 
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The center toon has lifting strakes to my knowledge. The fouls are on the outer toons.
 
Then you have one buoyant mother.
 
Should have ordered sealed I guess but why would Benningon even offer the open strakes if the sealed has so many advantages for little extra cost. It would be nice to here from them on this. I just can't imagine they would allow an option like this to be dis-advantages to the boat's performance. There must be something we're not considering. Bennington, are you out there?
 
Dan S said:
Should have ordered sealed I guess but why would Benningon even offer the open strakes if the sealed has so many advantages for little extra cost. It would be nice to here from them on this. I just can't imagine they would allow an option like this to be dis-advantages to the boat's performance. There must be something we're not considering. Bennington, are you out there?
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I very highly doubt it affects performance in any way, despite the numbers posted here. Only Bennington engineering knows for sure. My ESP has open strakes and performs superbly in every way - handling, acceleration, and top end.
 
TomS said:
I very highly doubt it affects performance in any way, despite the numbers posted here. Only Bennington engineering knows for sure. My ESP has open strakes and performs superbly in every way - handling, acceleration, and top end.
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I agree there is no performance difference assuming the dimensions are the same and they empty quickly.  The reason I went sealed was because of invasive species and generally keeping them clean inside....not for performance reasons.

The reason I did the math was because i couldn't believe how much extra buoyancy they added...and I was bored since it is so f'n cold outside :-(

If you aren't in salt water, don't have concerns about invasive species or worries about freshwater growth in them, I wouldn't worry about your decision....Hell, I wouldn't worry regardless...You bought a Benny so you didn't have to worry!
 
I may make it down to Florida before I wear this boat out so that is why I ordered the salt water package and sealed strakes.
 
My thoughts are that it is a cost issue. It is cheaper to build boats with open strakes. I think most people can not tell the difference between open and closed. There are some legit reasons for running a closed/sealed strake and Bennington offers the option--at a price. As I see it, these legit reasons are for salt water applications, cleaning within the strake, critters hitching a ride, growth within the strake and better performance. I think all the reasons with the exception of better performance are easy to understand and most people will make their decision within those parameters with the added benefit that there "may" be better performance. For me, I believe there is better performance for a variety of reasons. However, my background is from Hi Po boats and building motors in the past and always looking to go faster, turn sharper, accel quicker etc in cars, motorcycles etc.

For me, in testing different toons, including benningtons with and without sealed strakes, I believe there is a difference. Maybe it is minimal and maybe it is in my head, but I think it is a performance advantage that is worth the money to me. I will say in the open strakes it does feel a bit more "settled" at low speed/idle. Again all subjective. I do not know if it is a product of additional weight or what, but it is hard to describe. To me it has better holeshot, planning and handling with sealed strakes. If I didn't have sealed strakes, I wouldn't worry about it. Since, I had a choice, I got it. My wife keeps telling me to grow up. It sure is hard.

Cheers, Steve
 
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