# Float pods



## CodyW (Jan 26, 2016)

I trying to debate if I can gain a few inches with pods on my 13 ft boat. It is 4 ft wide at the transom and wondering if I made the adding weight of the pods will make no difference in the draft. So basically what I'm asking is the ones that have smaller boats if float pods made a substantial difference?


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## Smackdaddy53 (Dec 31, 2012)

It depends on the weight of the pods and current draft of your boat. Calculate the approximate volume of the WET pods and figure out how many cubic feet the volume you will add. I did a lot of research before fabricating pods for my last aluminum boat and realized how many people were under the impression that the total volume of the pods are proportional to the floatation they will add which is completely wrong. One cubic foot AT OR BELOW THE WATER LINE will float approximately 60 pounds. It would be hard to make pods so heavy that they cancel out the extra floatation they would add. You should do some research on what angle to make the bottom of the pods in relation to the boat so you are not screwing up the attitude your boat runs by angling the pods up or down too much causing porpoising or digging.


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## WhiteDog70810 (May 6, 2008)

What size motor is your hull rated for? If your transom is 4' wide, you might have enough space to add sponsons that are big enough to actually help if you keep the motor light. The split tail of the Solo skiff, a narrower hull, works well, but it works because the boat is rated for up to 5 HP. If you are trying to hang a 15 HP, I don't know if you can add enough displacement to matter on a 4' wide transom without making the sponsons obnoxiously long. You'd want to calculate the displacement prior to the work to make sure it was worth the effort.

Nate


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## commtrd (Aug 1, 2015)

The solo skiff would be a heck of a lot more fishable if it was at least a foot wider, the stern was re-designed to provide more flotation, and the entire bow space was actually useable. Some things I have noticed from using my solo skiff. In other words, I would recommend being pretty critical when looking at a microskiff to really visualize actually using the boat out fishing. I did not realize these things when I chose to buy and outfit a soloskiff and a trailer. Money that should have been spent on my boat instead.


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## CodyW (Jan 26, 2016)

Smackdaddy53 said:


> It depends on the weight of the pods and current draft of your boat. Calculate the approximate volume of the WET pods and figure out how many cubic feet the volume you will add. I did a lot of research before fabricating pods for my last aluminum boat and realized how many people were under the impression that the total volume of the pods are proportional to the floatation they will add which is completely wrong. One cubic foot AT OR BELOW THE WATER LINE will float approximately 60 pounds. It would be hard to make pods so heavy that they cancel out the extra floatation they would add. You should do some research on what angle to make the bottom of the pods in relation to the boat so you are not screwing up the attitude your boat runs by angling the pods up or down too much causing porpoising or digging.


I'm rough guessing that the pods I make will add 20lbs to the back. I might get some foam blocks and try to figure out how to mount them solid to the transom for a trial and tune.


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## CodyW (Jan 26, 2016)

WhiteDog70810 said:


> What size motor is your hull rated for? If your transom is 4' wide, you might have enough space to add sponsons that are big enough to actually help if you keep the motor light. The split tail of the Solo skiff, a narrower hull, works well, but it works because the boat is rated for up to 5 HP. If you are trying to hang a 15 HP, I don't know if you can add enough displacement to matter on a 4' wide transom without making the sponsons obnoxiously long. You'd want to calculate the displacement prior to the work to make sure it was worth the effort.
> 
> Nate


It's a boat I am building, I put a bigger transom on it because I already have a 30hp mariner that weighs around 177lbs. Just tossing some ideas around, who knows it might be better to get a light 25hp motor but can't imagine my self without a power trim n tilt.


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## hunter4626 (Aug 7, 2016)

CodyW said:


> It's a boat I am building, I put a bigger transom on it because I already have a 30hp mariner that weighs around 177lbs. Just tossing some ideas around, who knows it might be better to get a light 25hp motor but can't imagine my self without a power trim n tilt.


I just bought a brand new 20 hp zuk it came with power tilt,and elec start- I paid a little extra but that is what I wanted.-You can get the same options from 15hp and up.


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## WhiteDog70810 (May 6, 2008)

CodyW said:


> It's a boat I am building, I put a bigger transom on it because I already have a 30hp mariner that weighs around 177lbs. Just tossing some ideas around, who knows it might be better to get a light 25hp motor but can't imagine my self without a power trim n tilt.


What is the hull rated for? I don't think you can realistically add enough sponson to a 4' wide transom on a 13' hull to support 177#. You can build it heavy or add ballast to the bow, but that defeats the purpose of a 13' boat. Is the transom 48" at the widest? How wide is the bottom of the transom? I assume it is flat bottomed if we are talking about sponsons.

Nate


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## Smackdaddy53 (Dec 31, 2012)

WhiteDog70810 said:


> What is the hull rated for? I don't think you can realistically add enough sponson to a 4' wide transom on a 13' hull to support 177#. You can build it heavy or add ballast to the bow, but that defeats the purpose of a 13' boat. Is the transom 48" at the widest? How wide is the bottom of the transom? I assume it is flat bottomed if we are talking about sponsons.
> 
> Nate


Why do the pods have to support the full weight of the motor? As with all pods or even adding length to the stern the changes are solely supplemental. If he can get two cubic feet of wet floatation out of the pods that will add an additional 120# of floatation. Even if he only gets one cubic foot it will provide 60# extra capacity. Not arguing, just asking!


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## yobata (Jul 14, 2015)

What is a pod? Is it the same thing as a sponson?


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## Vertigo (Jun 3, 2012)

Unless the boat is stern-heavy, pods will make little or no difference to overall draft at rest and, if properly installed, won't influence draft on plane. What pods will do is float the stern higher in a stern-heavy boat. They will also help to prevent "stern squat" when attempting to get onto plane. If your boat is well-balanced, pods probably won't do much.


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## Smackdaddy53 (Dec 31, 2012)

Vertigo said:


> Unless the boat is stern-heavy, pods will make little or no difference to overall draft at rest and, if properly installed, won't influence draft on plane. What pods will do is float the stern higher in a stern-heavy boat. They will also help to prevent "stern squat" when attempting to get onto plane. If your boat is well-balanced, pods probably won't do much.


That's funny!
One thing you are right about is how they help the boat with stern squat when getting up but the rest makes no sense. Not trying to be "that guy" but your ideas negate each other. Unless the pods are heavier than the water they displace they will help draft at rest and on plane.


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## WhiteDog70810 (May 6, 2008)

Smackdaddy53 said:


> Why do the pods have to support the full weight of the motor? As with all pods or even adding length to the stern the changes are solely supplemental. If he can get two cubic feet of wet floatation out of the pods that will add an additional 120# of floatation. Even if he only gets one cubic foot it will provide 60# extra capacity. Not arguing, just asking!


You are correct, the pods don't need to carry all the motor, but is 60# of displacement worth the hassle? That is 2 square feet submerged 6". That is pretty deep for my tastes, but we'll roll with it for now. I don't know the math to do this right, so I will treat it like a floating box to generate some rough numbers. Since I am not figuring in the flare, the displacement will actually increase a bit with draft. 

The width across the top of the transom does not help us. We need the width of the bottom of the transom. If the sides flare out 6", that could mean there is really only 36" to work with. How far do the blades of the motor swing right and left? That must be removed from the middle. If the motor needs 18" to swing and you add 2" of buffer space, that means each sponson can only be 8" wide. At 8" wide, the sponson must be 18" long and draft 6" to displace 1 cubic foot of water. Also, the operator might be in the stern to start the motor. That is another 150+# to account for. I think the sponsons will be pretty deeply submerged. You now have some extra flotation, but at what cost? What affect will 18" long sponsons have on handling? They will not allow a 13' boat to operate like a 16' boat with the same motor.

These are very rough numbers based on my worst case estimates, so they only serve to illustrate the factors he must consider. In the end, I am concerned that he might be asking the extreme end of a 4' x 13' floating box to support too much weight. You can only bolt so flotation behind the transom before you get in the land of diminishing returns. The longer and narrower with sponsons are, the more they will impair performance.

He needs to sit down an crunch numbers to determine whether he can get enough displacement back there to matter.

Nate


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## Smackdaddy53 (Dec 31, 2012)

WhiteDog70810 said:


> You are correct, the pods don't need to carry all the motor, but is 60# of displacement worth the hassle? That is 2 square feet submerged 6". That is pretty deep for my tastes, but we'll roll with it for now. I don't know the math to do this right, so I will treat it like a floating box to generate some rough numbers. Since I am not figuring in the flare, the displacement will actually increase a bit with draft.
> 
> The width across the top of the transom does not help us. We need the width of the bottom of the transom. If the sides flare out 6", that could mean there is really only 36" to work with. How far do the blades of the motor swing right and left? That must be removed from the middle. If the motor needs 18" to swing and you add 2" of buffer space, that means each sponson can only be 8" wide. At 8" wide, the sponson must be 18" long and draft 6" to displace 1 cubic foot of water. Also, the operator might be in the stern to start the motor. That is another 150+# to account for. I think the sponsons will be pretty deeply submerged. You now have some extra flotation, but at what cost? What affect will 18" long sponsons have on handling? They will not allow a 13' boat to operate like a 16' boat with the same motor.
> 
> ...


That's more like it! 
If the pods were 18" long and 6" under water they would only displace 108 cubic inches, 144 cubic inches is a cubic foot so they would need to be about 24 1/4" long and 6" under to make a cubic foot of displacement each only if they are not angled on the outsides to match the hull. 
Going with a lighter motor is probably a better choice but yes he needs to run some measurements to see if it's worth the hassle.


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## WhiteDog70810 (May 6, 2008)

Smackdaddy53 said:


> That's funny!
> One thing you are right about is how they help the boat with stern squat when getting up but the rest makes no sense. Not trying to be "that guy" but your ideas negate each other. Unless the pods are heavier than the water they displace they will help draft at rest and on plane.


If you think Vertigo is wrong, read his post again carefully. He knows this stuff better than most of us. His point was that pods/sponsons add a trivial amount of displacement to a hull because they are so small in relation to the hull. If you balance the load so the boat floats level at rest, they probably decrease your static draft by about a millimeter or two. As he specified, they only help significantly decrease draft on a stern heavy boat (an very unbalanced load). They don't significantly affect draft on plane because once the boat is on plane, the lift created by the hull moving through the water dictates the draft. The sponsons once again have a trivial impact because they are such a tiny surface compared to the rest of the boat. Sponsons may help a boat plane quicker at a slower speed and improve hole shot, but those are different criteria.

Nate


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## CodyW (Jan 26, 2016)

WhiteDog70810 said:


> You are correct, the pods don't need to carry all the motor, but is 60# of displacement worth the hassle? That is 2 square feet submerged 6". That is pretty deep for my tastes, but we'll roll with it for now. I don't know the math to do this right, so I will treat it like a floating box to generate some rough numbers. Since I am not figuring in the flare, the displacement will actually increase a bit with draft.
> 
> The width across the top of the transom does not help us. We need the width of the bottom of the transom. If the sides flare out 6", that could mean there is really only 36" to work with. How far do the blades of the motor swing right and left? That must be removed from the middle. If the motor needs 18" to swing and you add 2" of buffer space, that means each sponson can only be 8" wide. At 8" wide, the sponson must be 18" long and draft 6" to displace 1 cubic foot of water. Also, the operator might be in the stern to start the motor. That is another 150+# to account for. I think the sponsons will be pretty deeply submerged. You now have some extra flotation, but at what cost? What affect will 18" long sponsons have on handling? They will not allow a 13' boat to operate like a 16' boat with the same motor.
> 
> ...


Sounds like it won't be worth it. You are correct about me expecting a major difference in a small box. I feel I have the boat well balanced with gas tank and both batteries up front. I'm a little concerned about my 28gal live well I have in the middle. I mainly am looking to help with squat for take off.


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## Smackdaddy53 (Dec 31, 2012)

Do you have trim tabs?


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## Vertigo (Jun 3, 2012)

Properly installed flotation pods will actually be angled up slightly so as not to interfere with handling when at higher speeds. Some folks actually install the pods up an inch or two from the bottom of the boat. Thus, properly installed pods will have little or no effect on draft or planing at speed. If a boat is well balanced at rest (not stern heavy), pods will be un-submerged or only slightly submerged, thus they will have little effect on draft. I hope this clarifies my previous post.


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## CodyW (Jan 26, 2016)

Smackdaddy53 said:


> Do you have trim tabs?


No, I don't know much about them or how well they help.


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## Smackdaddy53 (Dec 31, 2012)

CodyW said:


> No, I don't know much about them or how well they help.


Since you are wanting to lift the stern while jumping on plane I think they are worth a look.


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## CodyW (Jan 26, 2016)

Smackdaddy53 said:


> Since you are wanting to lift the stern while jumping on plane I think they are worth a look.


So, what kind should I be looking at? I see electric, self leveling, and smart tabs.


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## Smackdaddy53 (Dec 31, 2012)

What kind of boat do you have? As of righg now all I know is you have a boat with a 48" wide stern that you want better holeshot out of. 
Personally I hate fixed trim tabs and prefer Lenco electric tabs.


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## CodyW (Jan 26, 2016)

Smackdaddy53 said:


> What kind of boat do you have? As of righg now all I know is you have a boat with a 48" wide stern that you want better holeshot out of.
> Personally I hate fixed trim tabs and prefer Lenco electric tabs.


here is with hull only










with motor and no gear or fuel










Tape stayed at the same spot for both pics.


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## Smackdaddy53 (Dec 31, 2012)

Maybe soneone else will chime in but with no center console you may be better off with fixed tabs or adjustable tabs.


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## Vertigo (Jun 3, 2012)

Fixed tabs set to aid hole shot will seriously detract from planing performance. Adjustable tabs are expensive. If a boat is well designed and properly balanced, chances are adjustable tabs will not give enough benefit to justify the cost and complication. The OP's hull looks like it will balance nicely once finished and loaded. I'd run without tabs to start and then make a decision based on observed performance.


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## CodyW (Jan 26, 2016)

Vertigo said:


> Fixed tabs set to aid hole shot will seriously detract from planing performance. Adjustable tabs are expensive. If a boat is well designed and properly balanced, chances are adjustable tabs will not give enough benefit to justify the cost and complication. The OP's hull looks like it will balance nicely once finished and loaded. I'd run without tabs to start and then make a decision based on observed performance.


I think I'm going to put on a good hydrofoil and a better prop and go from there. I had this motor on another boat that was the same size but a foot longer that was stern heavy and did good, was able to jump on around a foot n half of water.


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