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Old 18-04-2008, 17:33   #1
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Prop Cages/Guards?

Does anyone have any information on how much loss of performance prop cages would cause?

I'm talking about something like this:

http://www.oceansafety.com/images/Co...ropellorGu.jpg

Any data on loss of speed? I'm consistently trying to tune up the boat to get her going as well as possible. This is something the boat has that I might remove to get her sailing fast again.
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Old 18-04-2008, 17:58   #2
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Does anyone have any information on how much loss of performance prop cages would cause?.
Very nice looking speed brakes Sean!!
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Old 18-04-2008, 20:26   #3
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Cage drag

Considerable. I used to drive various boats with prop cages in Maine to avoid fouling lobster pot warp. The loss of power and speed was dramatic, especially with an OB. We eventually abandon them in favor of greater vigilance.
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Old 19-04-2008, 01:17   #4
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Dang they're ugly. Ditch them Sean. A lot of drag there mate. I have certainly seen some prettier ones than that. But in all honesty, the only protection they end up offering is if you beach the boat. The guard protects the prop. There is another more simpler approach to protecting the prop. That is a piece of thin plate SST bent in a circle and bolted to the planing fin on the leg. The thin plate encircles the prop to protect it. It works well. Thundercat racing inflatable use them because the boat comes screaming up onto the sand beach.
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Old 19-04-2008, 04:47   #5
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Great replies. Thanks!

Woodstock, since I'm not back in Maine, yet, you were *exactly* the kind of person I was hoping to hear from.

I know a lot of lobster boats in Maine use them, but I didn't know what they gave up in performance when doing so. Sounds like a lot.

My cages are attached to the hull and enclose the Yanmar SD20 saildrives. I hadn't been getting the claimed speeds out of the boat, and now I think this is why. Taking them off while on a delivery from the Keys to Maine is likely to save me hundreds of $$ in fuel and days of travel time. They're coming off this week! ha ha

Now what to do with the holes in the hull... ??

There are 3 bolts for each prop cage coming through the hull. I have to take them off and fill the holes - at low tide - to dry by high tide. Maybe Marine-Tex, I think.

PS: Great company, Jeff. That's probably one of the most important bits of training an offshore sailor (or even remote anchorer) could ever need. There is a thread on alternative medicine going, but to me, knowing how to deal with trauma quickly and efficiently is the absolute most important thing on boats. If someone injures themselves on my boat, I'd like to be able to stabilize them for the long wait they are in for before medical services can reach them. Cool.
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Old 19-04-2008, 04:50   #6
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Dang they're ugly. Ditch them Sean. A lot of drag there mate. I have certainly seen some prettier ones than that. But in all honesty, the only protection they end up offering is if you beach the boat. The guard protects the prop. There is another more simpler approach to protecting the prop. That is a piece of thin plate SST bent in a circle and bolted to the planing fin on the leg. The thin plate encircles the prop to protect it. It works well. Thundercat racing inflatable use them because the boat comes screaming up onto the sand beach.
And they don't even protect the props when beaching, since my saildrives are quite a bit higher than the lowest point of the forward hull and my rudder skegs. There is no reason for them other than line entanglement and a good brake if you're going too fast.

They are custom-constructed stainless steel, not the ones pictures in the photo. I couldn't find a perfect example. These have quite a few supports and bars, like in the photo though... plus 3 holes in the hull each to keep them in place.
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Old 19-04-2008, 05:46   #7
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Sean, 3M 5200 quickset will take a bit to cure but will cure under water.
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Old 19-04-2008, 06:04   #8
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Sean, 3M 5200 quickset will take a bit to cure but will cure under water.
I didn't think 5200 was a good thing to patch holes with. Isn't it just an adhesive?

Plus, as you said... it won't set in time for the tide. Way too scary. Marine-Tex sets in 20 mins or so and is a 2 part epoxy type material.

But... is there anything else people use to fill holes in solid glass hulls while out of the water for a few hours?
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Old 19-04-2008, 09:44   #9
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"That is a piece of thin plate SST bent in a circle and bolted to the planing fin on the leg. "
The cheap man's Kort Nozzle. <G> And while a Kort nozzle should increase prop efficiency by creating an end plate effect, that mess of steel rods should create lots of turbulence instead.

So you made it back North, Sean?
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Old 19-04-2008, 09:58   #10
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"That is a piece of thin plate SST bent in a circle and bolted to the planing fin on the leg. "
The cheap man's Kort Nozzle. <G> And while a Kort nozzle should increase prop efficiency by creating an end plate effect, that mess of steel rods should create lots of turbulence instead.

So you made it back North, Sean?
Nope. En route. Working on it. Maybe the prop cages are holding me back?
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Old 19-04-2008, 10:41   #11
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Ditch the cages and put on Spurs?
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Old 19-04-2008, 10:42   #12
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Ditch the cages and put on Spurs?
Na... I can't afford to add things to the boat. Only take things off.
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Old 19-04-2008, 10:46   #13
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But... is there anything else people use to fill holes in solid glass hulls while out of the water for a few hours?
Never been brave enuf to do something like that between tides (says more about my trust in me, than what is possible ).....would wait until the boat was neaped for a few days.

But, my thinking is.......if you can't make a permanent repair now - then why not put the bolts back in with a bit of sealant?....even if you have to shorten or reverse the bolts?......of course that presumes they come out in the first place!!

Those cages sound like they would do well on E-Bay......even if on a Motorboat......maybe take a couple of photos in situ before removing?
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Old 19-04-2008, 12:22   #14
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Never been brave enuf to do something like that between tides (says more about my trust in me, than what is possible ).....would wait until the boat was neaped for a few days.

But, my thinking is.......if you can't make a permanent repair now - then why not put the bolts back in with a bit of sealant?....even if you have to shorten or reverse the bolts?......of course that presumes they come out in the first place!!

Those cages sound like they would do well on E-Bay......even if on a Motorboat......maybe take a couple of photos in situ before removing?
Good thinking, David!

I'll see if I can unbolt them and eBay. Who knows... maybe they could make up for the price of a proper haul out where I can get everything done in a couple days, rather than over a week waiting for tides.

My other plan, to avoid messing with the holes was to hacksaw them off. Seems a little crazy when they are worth something... then again... since they are custom to this boat's hull shape and Yanmar SD20's, maybe they're not worth anything but stainless steel scrap?
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Old 19-04-2008, 14:44   #15
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I don't know what Marine-tex is, but if it is Epoxy, it will be a good choice. Or refit the bolts would also be a good choice. Do you have "Selleys'" products in the US?? Selleys have epoxy putty's called "Kneed-it". Several choices available and several other brands also put out the same stuff. The two parts come rolled together and you simply cut off what you need and start Kneeding it to mix the parts together. There are different cure rates, but they usually harden anywhere from five minutes to 20minutes and they will continue to cure even underwater. This can remain as a permanent repair. When you finally get home, you only have to sand back fair and paint over. Maybe your Marine-tex is the same stuff.
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