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Dingy home made flotation tubes... your input...

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britinusa
Web Editor

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USA
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Response Posted - 04/04/2012 : 04:16:46

Not sure how long those air bubble retain their internal pressure.
My concern would be the potential pollution from the bean bag fill.

Using zip lock bags to hold the 'beans' would certainly limit the consequence of a punctured tube. Could you use that technique for the entire length of the tubes Henk?

Paul

Edited by - on

JohnP
Master Marine Consultant

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Response Posted - 04/04/2012 : 05:23:33

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by britinusa
 Not sure how long those air bubble retain their internal pressure. <hr height="1" noshade id="quote"></blockquote id="quote">
Yeah, good point! I doubt that Practical Sailor magazine has done torture tests on marine uses of packing bubbles of various sizes. They would need to be inflated but not burst from icy ocean temps of 5 degrees C to the hot summer heat of about 30 degrees C.

They're not designed for that, but who knows!

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 04/04/2012 : 09:39:35

Always interesting to consider different materials and to try new, economical ways of doing things. Packing material is certainly one of them. Just the other day someone told us that they use "packing bubbles", for insulating walls and as sound barrier.

Thanks for your valid points...

Using smallish compartmentalized Polystyrene bead (zip)bags makes a lot of sense. Most probably it would stuff well enough to fill the tube. Each little bag would need to be foreseen with very tiny air-holes to bleed the air when stuffing and hand compressing the tube.

In case of a puncture only a small amount would potentially spill.

In fact this method would not be unlike using "packing bubble", material but without expanding and contracting air worries.

Thanks for the suggestions and help. Since this is just experimental and a fun project, we started with only one tube, I will try to use the lunch zip bag approach for the starboard tube. To make the bags "slippery", we'll treat them with cornstarch or Talcum powder... any suggestions guys??

Edited by - on

TakeFive
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Response Posted - 04/04/2012 : 09:57:50

I use bubble wrap as insulation in my settee lockers. In the early season, when the hull interior below the waterline tends to attract condensation because it's below the dew point (which gets worse with increased ventilation!), the bubble wrap prevents this condensation. I described it [url="http://www.sailnet.com/forums/gear-maintenance/65243-using-bubble-wrap-minimize-moisture-settee-lockers.html"]here[/url], and endured the usual barrage of SailNet skeptics.

One concern I have about your styrofoam beads is the possibility of semi-permanent moisture uptake, since they are probably not closed-cell. Before you get too intricate with extra plastic bags, etc, you might want to run a quick experiment where you fill a lightweight open mesh bag (womens' hose would do well), weigh on a postal scale, immerse in water for an hour or so, dry for a couple hours, then weigh again. If it picks up weight, continue to weight it over a period of days to see how slow the drying process is. I am concerned that even a tiny puncture or leak along the seam could cause the styrofoam to imbibe water over time. I know that polystyrene is very hydrophobic, but without a closed-cell structure you might find yourself culturing a nice colony of mold inside your tubes.

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JimGo
Admiral

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USA
962 Posts

Response Posted - 04/04/2012 : 11:16:57

Rick, didn't you see that Henk was also using the tubes as a biofuel farm?

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 04/04/2012 : 14:53:30

Doctor... thank you for your bubble wrap clarification as per
http://www.sailnet.com/forums/gear-maintenance/65243-using-bubble-wrap-minimize-moisture-settee-lockers.html

My question is would this also work beneath the cushions in the aft berth area... we presently use 2x2 interlocking 1/2" fatigue mats and still observe albeit reduced moisture

You're addressing a nagging, in the back of my mind, thought about potential moisture buildup inside the tubes ever since we switched from the sewer pipe to the tubes concept. Although we will glue protective 1.5" strips over all joints and sewn parts my question is will there be a due point effect due to temp changes or what about if some moisture penetrates from the outside...

Thanks for the suggestion to test, what I assumed, is a closed cell Polystyrene material for a couple of days... we'll follow up and report

Should I drill a small screened and capped ventilation hole in the wood stern block for ventilation and as a possible moisture drain

Wouldn't it be fun to use the tubes for production of a fuel source to drive the outboard, for cooking or grow alfalfa sprouts...

Edited by - on

crystal_blue
1st Mate

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USA
70 Posts

Response Posted - 04/04/2012 : 15:03:10

Henk, I'm not sure if you ever decided on a way to keep these things from riding up as the dinghy tips; but why not just cleat them off fore and aft as per the Dinghy Dogs and then connect the two tubes to each other with a couple of strips of nylon webbing that pass under the hull? That way you wouldn't have to go drilling holes in your hull near/below the waterline.

--Jim

Edited by - crystal_blue on 04/04/2012 15:03:54

TakeFive
Master Marine Consultant

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2272 Posts

Response Posted - 04/04/2012 : 17:15:11

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by zeil
 ...My question is would this also work beneath the cushions in the aft berth area... we presently use 2x2 interlocking 1/2" fatigue mats and still observe albeit reduced moisture...
<hr height="1" noshade id="quote"></blockquote id="quote">
The 1" bubbles that I used are not very durable, so would not work well in an area that gets significant weight and/or movement. I've been intending to upgrade to something a little better, but it's still working well for now. Two years ago I splashed in late March, and the water temperature was much colder than what I've experienced since, so the problem is not a big one right now.

If you're just storing stuff in the aft berth (and not sleeping there) you might try some of the stronger bubble wraps with smaller bubbles and antistatic metallic coating.

Also be sure the moisture is actually condensation, and not a leaky bedding in the battery storage area or leaky cockpit cubby.

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 04/05/2012 : 11:38:41

James... strapping the two floatation tubes together below the hull could be done with some potential resistance and picking up foreign material while underway. However the straps still need to be fastened somehow to the hull to prevent shifting during unequal loads.

So... may as well experiment, as per Dingy Dog's illustration, with the center located PVC tube and 18" wide tube-strap approach to be attached to the side of the dingy unless someone can come up with a better way of securing the lightweight tubes.

Doctor... the condensation forming below the fatigue mats with the cushions on top was noticed just where the two cushions meet in the middle and after some one slept there for a few nights. It was minor.

Yes... we did have water/fuel penetration years ago through the seal in the fuel tank/deck area when inadvertently after leaving the vent on the fuel tank open and towing the boat home over a rough road that, horror of horrors, fuel leaked into the aft berth area.

It could have cost us our lives with only one static spark exploding and setting the boat on fire...

Please check your fuel tank seal to make certain that there are no leaks of any kind

Edited by - on

TakeFive
Master Marine Consultant

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Response Posted - 04/05/2012 : 12:54:23

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by zeil
 
... we did have water/fuel penetration years ago through the seal in the fuel tank/deck area when inadvertently after leaving the vent on the fuel tank open and towing the boat home over a rough road that, horror of horrors, fuel leaked into the aft berth area...<hr height="1" noshade id="quote"></blockquote id="quote">
I'm not clear on what seal you are talking about. Do you have any penetrations through the floor of your fuel locker into the battery compartment below? I do not, but when shopping for boats I saw a C250 that did have such a penetration - someone had cut a hole there to pass the alternator/starter cable down to the battery. At the time I told the broker that I thought it was a safety issue for the very reason that you indicate here.

Edited by - on

waterbaby
Navigator

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USA
168 Posts

Response Posted - 04/06/2012 : 13:25:35

Ok, I can't resist. I really know nothing about this except that awhile back I stumbled onto a video that was interesting and it seems that some of the concepts in it could be applied here. Your dingy has a lip that you could bolt the frame onto...

Here's the video, it starts out a little weird but hang in there...
http://www.youtube.com/watch?v=VPog14El4H0

Heres the web site:
http://rebelcat.com/

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 05/15/2012 : 22:31:51

Finally had a little time to work on the project which apart from mounting the floatation tubes is nearing its completion... We're waiting for some SS mounting hardware to fasten to tubes midships. Here are some images...

In order to adjust the tubes I've made a the stern attachment adjustable by about 4" up/down

Edited by - on

Prospector
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Canada
3159 Posts

Response Posted - 05/17/2012 : 08:13:57

Henk,

I was just in SAIL outdoors store http://www.sail.ca/en/home/ and saw sponsons for canoes priced at $59.00 each. Seems like you wouldn't need more than 4 of them. 2 is probably enough. These are replacements for the sportspal canoe floats (one of the worst canoe designs in the history of the world)

You already have more than $100 in this in your time and materials.

Of course I totally respect and understand the DIY and pride of manufacturing piece, but it seems like a reasonable alternative.

Edited by - Prospector on 05/17/2012 08:15:16

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 05/18/2012 : 12:35:54

Chris... am curious... searched the website at http://www.sail.ca/en/home/ but could not locate the "sponsons", you mentioned

Project costs for just the material run a little higher than $100.00 including the tubes, fill material plus teak, glue, SS fittings and miscellaneous. However... if it works out it will save the cost of having to buy something else besides having a not too strenuous winter project.

Edited by - on

Prospector
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3159 Posts

Response Posted - 05/18/2012 : 12:41:52

I saw them on the floor in the shop. When I called back to get info for your thread, the clerk was very helpful, but I couldn't find them on teh website either (even with the clerk's help).

Here is a pick stolen from the interweb showing a sportspal in action:

These guys also carry the sponsons for $109 per set of 2 http://www.castlecraft.com/sportspal_parts.htm Maybe they were in sets of 2 at SAIL as well. I dunno. I didn't look that closely. They would easily be shippable, and SAIL has phone order information on the website. I was in the Oshawa store and saw the floats there if you want a specific store to call and get details.

I would try giving SAIL a call on their 1-800 number and see if they can help. Otherwise see if there is a hunting/fishing place near you selling the sportspals. They really are a miserable beast to paddle/portage, so you likely won't find anyone selling parts for them in a reputable watersports place. I think a lot of hunter/fisherman types like the sportspals though.

A little more googleing brought up a shop in Abbotsford that will orde in Sportspals if they have to. http://www.westerncanoekayak.com/sportspal.php I am sure you can find another dealer in your own backyard.

Edited by - Prospector on 05/18/2012 12:58:08

John Russell
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USA
3444 Posts

Response Posted - 05/18/2012 : 12:48:52

I don't understand the purpose of the tubing from the stern and plywood at the aft end of the tubes?????

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zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 05/18/2012 : 21:10:15

Thanks Chris... looks interesting and something that would work well and easy to install to increase the stability of our dingy... I'll follow up and investigate before I start drilling holes to mount our home-made floatation tubes.

John... the teak wood parts are: 1) side rail extension about 8" past the stern of the boat complete with a 2) teak wood sliding panel screwed to the floatation tube in order to adjust the tubes about 4" up depending if the boat is towed (with no or less drag) or down for shuttling around in a harbor.

I purchased 1x6" "farmed teak", for $5.50 per ft instead of the usual $35 to $40 a foot.

The purpose of the 5/8" aluminum round is to brace sideways motion of the floatation tubes while allowing for the up/down adjustments. The aluminum brace is attached on the stern of the dingy to an existing bolt and will hold the back of the floatation tube in place. No new holes needed to be added/drilled in the hull.

It's all in an experimental stage at this point and am not sure if it will work, is over constructed or needs a different approach.

The concept is to be able to quickly remove both floatation tubes with it mounting hardware for trailer or truck transportation or perhaps when towing long distances if the tubes prove to be dragging.

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delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 05/18/2012 : 21:29:55

Here are the sponsons: http://www.westerncanoekayak.com/product_spec.php?item_description_id=6230

$65 CAD/pair

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Barn
Deckhand

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1 Posts

Response Posted - 05/22/2012 : 10:40:34

hey.. how you doin guys..?
new to this forum and I'm glad I open this thread.. learn some things on it..

nice boats you got there..

Edited by - on

Prospector
Master Marine Consultant

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Canada
3159 Posts

Response Posted - 05/22/2012 : 11:26:58

Thansk Barn - welcome aboard - what is your boat?

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8chenuu
Deckhand

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USA
3 Posts

Response Posted - 05/26/2012 : 04:55:07

Actually the website, http://dinghydogs.com, shows $425 to US and $445 to Canada with shipping included.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Sam001
 I thought the dinghy dogs were pricey at $495.
at the web page
<hr height="1" noshade id="quote"></blockquote id="quote">

Edited by - 8chenuu on 05/26/2012 04:58:22

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 06/06/2012 : 21:58:58

Some progress... dingy floatation tube project is getting closer to completion... here are a few images of the mid ship attachment

The mid ship attachment flap is measured, cut and ready to be glued to the insert pipe

SS brackets bolted thru the hull with 1/4 thread, reinforced with ss washers on the inside holding the 11/4 od plastic pipe with 3/8" wide slot. A teak end block caps the inside of the forward holder. This arrangement is not intended to be removed

Flap glued to pipe ready to be inserted.

Floatation tube flap ready to slide underneath the floatation tube from stern to bow into the slot...

Edited by - on

JohnP
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1520 Posts

Response Posted - 06/07/2012 : 06:56:13

Henk,

Looks like you've got the job all done. Looks really good!

I'll be in Vancouver on June 19th - 23rd for a conference, and I would enjoy meeting you and the Admiral for coffee one of those afternoons or evenings, if you're available. I could bring along my photos of the 200th anniversary celebration of the start of the War of 1812 and the tall ships visit to Baltimore Harbor. I'll be avoiding collisions next week when I take a few days off to go sailing on the Chesapeake Bay.

You could send me a PM if you like.

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 06/07/2012 : 22:27:56

Made a little bit more progress today...

Attachment method at the bow... the teak wood block remains part of the floatation tube. This is attaches to the permanent through-hull 1/4 bolt with a wing-nut

The 1/4" through-hull bolt is reinforced with a3x3" 1/4" thick pvc backing plate and washer (pvc is cut, heated and reshaped from a previous purchased 6" sewer pipe)

Midships floatation tube suspension method. The pvc 1 1/4" pipe is bolted in place with slot facing down. The cut-in-two pvc pipe holding the fabric is inserted from both ends into the larger tube.

Midships view of the floatation tube suspension. The fabric is glued to the inside of the tube

Stern teak wood adjustable floatation tube device with pin-locks and alum tube brace. The top side arm lock will allow to remove and store the teak wood plunger. The bottom teak housing is part of the floatation tube.

The housing is complete with a ss lock-pin held in place with a simple wooden lock. Move the lever horizontally remove, reinsert, press down and lock in place.

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 06/20/2012 : 09:39:34

Final version of the dingy floatation tube project

Dingy with stern attachments and floatation tubes inside the dingy under the tarp

Permanent floatation tube attachment rail with teak "torpedo"

Ready for transportation with tubes stored inside... It takes less than 5 minutes to attach both tubes

Method of storing the floatation tubes with tarp center rail shown

Final version of stern floatation holder... the slot in the teak allows the cover tarp wrap around the hull

Two small teak plugs added for snugging the tarp around the stern

Bow floatation tube attachment to hull. Bolt is permanently secured with lock nut. The removable tubes are attached with wing-nut and lock-washer.

Bow floatation tube storage during transportation or winter storage

Stern view of the floatation tubes with aluminum side sway bars.

Stern attachment detail with wrap-around for the tarp

Dingy equipped with home-made floatation tubes. Each tube should have approximately 120-140 lbs lift fully submerged.

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