[PSUBS-MAILIST] Minn Kota C2 vs Riptide

Sat Jul 13 08:20:50 EDT 2019

Hi Tim,

I have two never-installed Minnkota 74lb lower ends, which I bought years
ago but never installed because I changed the design to 101s. They can run
on either 24 or 36 volts, and were the salt water version. Let me know if
you could use these, I can surely sell them for less than you were quoted.

Best,
Alec

On Fri, Jul 12, 2019 at 8:38 PM T Novak via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> It is time to re-motor the SportSub.  Currently it has 42lb thrust Minn
> Kota motors, one corroded and unusable, the other working well.  Locally I
> can pick up the Endura C2 40lb for $250, or the Riptide 45lb for $400. The
> Riptide is marketed for salt water use.  Has anyone any advice as to
> whether or not the Riptide is worth the extra $150? The extra 5 pounds of
> thrust is not relevant since the hull is far from hydrodynamic efficiency
> and I would just us more battery power to go no faster. The thrusters must
> have the same thrust rating, so I need to get two new.
>
>
>
> Tim
>
>
>
> *From:* Personal_Submersibles [mailto:
> personal_submersibles-bounces at psubs.org] *On Behalf Of *hank pronk via
> Personal_Submersibles
> *Sent:* Friday, July 12, 2019 5:57 AM
> *To:* Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org
> >
> *Subject:* Re: [PSUBS-MAILIST] Foam preperation
>
>
>
> Brian, thats' a good plan.  The cheapest way to gain buoyancy is to remove
> weight if possible.
>
> Hank
>
>
>
> On Thursday, July 11, 2019, 6:44:00 PM MDT, Brian Cox via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
>
>
>
> Hi all,
>
>                    I think I'm going to do another test with that foam.
> This time I will encapsulate it with epoxy and fiberglass and drop it down.
>
>
>
>   My sub is going on a serious diet.  I'm cutting out a significant
> section of the upper ferro-cement area and replacing it with
> epoxy fiberglass which will be bonded to the ferro-cement.  It will be a
> bit different shape, but the whole area is underneath the fiberglass shell
> so it won,t really look any different with the shell on.   I always though
> I could compensate for that weight by having flotation cylinders there but
> I just didn't control the thickness of the ferro-cement and it probably
> should have been fiberglass all along anyway.  The bottom of the ferro
> ballast hull will still be the the existing hull .  It will be a lot of
> weight that I'll be losing.  Maybe 1,500 lbs, if the section I cut out is
> any indication.
>
>
>
> Brian
>
>
>
>
>
> --- personal_submersibles at psubs.org wrote:
>
> From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org
> >
> To: "Personal Submersibles General Discussion" <
> personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Mon, 8 Jul 2019 23:17:21 -0700
>
> Alan,
>
>              Yes it's puzzling the mechanism at work allowing it to take
> on water.  It could be that the small bubbles of foam that make up the
> matrix of the foam itself are simply not strong enough to handle the water
> pressure.  But it's interesting that it can take a rated pressure (
> parallel applied pressure) and not be crushed but then on the other hand
> will absorb water.  From the look of it you would never think that water
> would penetrate it, the outside of the foam seems nonporous.  Might be
> instructive looking at it under a microscope.
>
>
>
> Brian
>
>
>
>
>
> --- personal_submersibles at psubs.org wrote:
>
> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Tue, 9 Jul 2019 16:57:52 +1200
>
> Brian,
>
> I am wondering how it absorbed water, seeing it's a marine product.
>
> Do you think there may have been a break down on a microscopic level
> through
>
> the water being forced in under pressure.
>
> Anyway, good that you got a result. Imagine if it had absorbed water more
> slowly
>
> so that it wasn't detectable in the short time that you tested it.
>
> Alan
>
>
> On 9/07/2019, at 1:43 PM, Brian Cox via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Bad news,  the test piece that I dropped down to 900'  , it didn't crush ,
> but it absorbed water.  So it lost a lot of its buoyancy.
>
>
>
> Brian
>
>
>
>
>
> --- personal_submersibles at psubs.org wrote:
>
> From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org
> >
> To: "Personal Submersibles General Discussion" <
> personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Fri, 28 Jun 2019 16:15:09 -0700
>
> Alan,              I've done one small test piece so far and it did give
> off some heat.  I'm planning on doing a larger piece that I'm going to drop
> in the ocean, it will be interesting to see how that goes.  I'm more
> inclined to pour larger amounts for a couple of reasons, first I think you
> get a better and more accurate mix of the A and B, and also where I'm
> pouring into my cavities I don't want to inadvertently seal off areas that
> I will not be able to get to to complete the pour.  So I'd rather error on
> over pouring a bit so I have foam pushing out the vent holes.
>
>
>
> Brian
>
>
>
>
>
> --- personal_submersibles at psubs.org wrote:
>
> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Sat, 29 Jun 2019 09:18:40 +1200
>
> All,
>
> as we are talking about testing this for General Psubs use I'll elaborate
>
> on something I mentioned earlier.
>
> In the product specifications below it mentions that in the setting of
> this product
>
> the temperature is critical, & that temperatures below 75 degrees F will
> make a
>
> denser product. One would assume that temperatures above 75 F would make
>
> a less dense & hence weaker product.
>
> With 2 part chemical reactions there is generally a heat produced & this
> is
>
> exponentially greater the thicker the pour. I used to use casting resins
> for art
>
> & they would get very hot on thick casts.
>
> If this were the case then filling any large voids in one pour may cause
> the
>
> centre of the material to be a lot weaker than the outside.
>
> To check this we could ask the rep about thick pours, do a thick pour &
> cut it
>
> in cross section to see if it is less dense in the middle or stick a heat
> probe in
>
> the middle of the pour to check for an increased temperature.
>
>    - All expansion rates and times given are temperature critical.
>    Temperatures below 75 degrees F will lower the expansion rate therefore
>    requiring more foam. Ideal working temperature is 75 to 80 degrees F or
>    above.
>    - Accurate measuring of these products is extremely critical.
>
> Alan
>
>
>
>    - All expansion rates and times given are temperature critical.
>    Temperatures below 75 degrees F will lower the expansion rate therefore
>    requiring more foam. Ideal working temperature is 75 to 80 degrees F or
>    above.
>    - Accurate measuring of these products is extremely critical.
>
> On 28/06/2019, at 11:04 PM, Jon Wallace via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Not my forte, but given the hardness of this product when cured is there
> really an expectation that it is going to deform in a visually measurable
> way and spring back into shape from a depth test?  Seems like it's more
> likely to either structurally fail or not with obvious non-elastic results
> such as cracks, cavities, etc, hence the weight test to see if it absorbs
> water.  I'm thinking the dunk test from the sailboat is a good first start.
>
>
>
> The cost of this product seems to be on par with trawler floats from a
> pound to pound buoyancy perspective but it has the advantage of allowing
> custom shaping.  I'm interested in the results.
>
>
>
> Should we invest in a small amount of this product and put it to some more
> rigorous pressure testing?
>
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