to pod or not to pod???

[tunaticer]

Hey good peoples,

I am starting a new hobby at the moment designing a boat and building it from scratch.
What are the advantages of running a pod as opposed to mounting the motor directly to the transom?

Is there a horsepower issue?

Is there an economy gain or loss?

How differently does it make your boat perform??

The hull i am designing is an open water hull 4.5m long and quite beamy, the hull will be 3mm alloy bottom and 3mm sides too most likely.

What floatation materials or comcepts are out there?

Jack.

[Chimo]

Jacks a game boy!!!!!!!!!!!!!

Good luck with the the hobby...............

Chimo

[Lovey80]

Tunaticer, as far as i know it, someone correct me if im wrong. The Pods allow the motor to be set back and further down towards the water. So if the option without a pod means having a transom that is cut low to fit the motor(usually water comes in over the back when reversing hard or slowing down fast off a plane) then having the pod elleiviates this. Aslo as far as i know the pod provides extra buoyancy to the rear of the boat which may make the differenc where weight is concerened. This can become important if you want to fit a 4S instead of going a lower HP you get the same size instead of reverting back to a 2S.

Hope i havent given you a bum steer.

Cheers Chris

[Lovey80]

On the flotation materials. Why not fill any sealed compartments with a buoyant foam material. If you do hole it its not going to become a device that will hold water. Just my 2 cents

Cheers Chris

[tunaticer]

Thanks Chris, thanks Chimo.

I am sort of steering away from foam materials for two reasons. If there is a fuel spill depending on the foam used it may either melt away or it may absorb it and absorb water over time as well thus removing its bouyancy. A lot of pontoons you see that are sitting either unevenly or low in the water are saturated foam floatation pontoons.
I have been playing around with two ideas in my head about bouyancy. Firstly using poly pipes sealed airtight un the underfloor areas or fabricating poly air tanks for the underfloor area.
Are there any "air bladders" currently on the market that can be fitted underfloor and inflated?

I am also fairly certain that i will be using 2st direct injection motor rather than 4st.

Jack.

[Luc]

Just fill your flotation spaces with empty plastic bottles.

Re pods, one of their main use is to offset the weight of 4 stroke engine particularly on boats that are not particularly wide.

Helps to stop the boat being heavy arsed.

Luc

[FNQCairns]

Enticer in a former boating life we used to use tyre tubes but that may-not suit your application but was perfect for ours.

cheers fnq

[Lovey80]

I suppose at the end of the day it will be you that decides how much weight the stern of your boat can handle but most of the time especially with tinnies the weight can easily get uneven at the back. I say go the pods without question.

At the end of the day its all about your buoyancy calculations. If theres going to be significantly more weight towards the back then you need more buoyancy in the back. The pods will come intoplay when you consider live bait tanks and battery shelves etc. So if you want the bigger heavier engine and the live bait tanks you may want to go the pods. PM me if you want tips on Buoyancy calculations.


Cheers Chris

[Noelm]

don't know about a pod being used to support more weight in the back, the extra length the motor is "set back" can sometimes increase the weight balance of the rear, but some "follow boat bottom" pods can ease this situation.

[Lovey80]

Noelm, if the pod is at or below the water line surely this will provide more buoyancy wont it?

Cheers Chris

[BM]

NOPE.........................

Its only providing bouyancy at rest in that scenario, which is not relevant. Once the boat is on plane, which is all that really matters, you wil have a gap between the water and the base of the pod.

This is where a canti lever effect comes into play and the unsupported engine is pulling down (due to its weight) with nothing beneath it to resist the weight force.

Cheers

[snapperm8]

Just pack under the floor of ur tinnie with polystira foam.. if you lift up the floor of alot of tinnies you'll find its foam packed in there. please correct me if im wrong but im pretty sure of this.

but the fuel and foam thing would be an issue but nothing has gone wrong with the foam under our floor.. unlikely you will spill fuel inside the boat usually you fill it up from outside.. you are going to have an underfloor fuel tank?

cheers dave

[tunaticer]

Thanks fellas,

I am designing the boat with an extended bottom back to the "pod" i am integrating into the boat.
I will have two underfloor fuel tanks on board both 80L each.
Flotation in the pod will be a sealed tank within the pod but drainage for the entire boat will come thru that sealed tank via a pair of 2" drainage pipes to the transom directly under the motor.
I have integrated 3 sealed alloy floatation tanks full width of the underfloor section and countoured to fit the cavity properly spaced evenly throughout the boat. I will fill any other voids with sealed milk bottles due to thier nil cost and availability and replaceability.

Jack.