Airdeck Keel Board Redesign

Steve509926 · 17 January 2022, 19:51

The original Airdeck Keel Boards that came with Redneck are made of lightweight carbon fibre plastic. The front board has always been ok but the rear board never fitted properly:-

https://www.rib.net/forum/attachment...8&d=1595707702

I ended up making a new one out of 18mm external ply, treated it with Zinsser 123 and overcoated with external gloss. After 18 months, approx 100 hrs, it has unfortunately cracked, no not through water ingress or wear and tear, I drove over it with the truck

So I need to make a new Airdeck Keel board. Recent threads about prop slip, overlaying airdecks with ply etc got me thinking if could come up with a better design. Hopefully I think I have.

The new Airdeck Keel Board you will see in the video is, for want of a better word, a prototype. If it works on the water, I will probably make another out of 12mm ply overlaid with glass and flowcoat/gelcoat.

Apologise for the sound quality, but I'm sure you will get the drift of what I'm trying to achieve.

https://www.youtube.com/watch?v=Jdjxm7utlIE

jeffstevens763@g · 17 January 2022, 19:59

How do you keep it in place Steve ?

Steve509926 · 17 January 2022, 20:09

I don't envisage it moving much, but when I've tested it on the water and convinced myself it's a success

I'll glue some bigger staps on the airdeck where the existing keel board straps are.

Limecc · 17 January 2022, 22:29

Brilliant idea.
Regarding holding it in place, it need only get tucked in one side or the other because it's one piece.

I wasn't aware you suffered with the bubble Steve. (Sounds like an affliction lol). I think raising the engine encourages it to happen so if you get it sorted then maybe you can tweak the setup and have it run even better.

Steve509926 · 17 January 2022, 22:41

Quote:

Originally Posted by Limecc

Brilliant idea.
Regarding holding it in place, it need only get tucked in one side or the other because it's one piece.

I wasn't aware you suffered with the bubble Steve. (Sounds like an affliction lol). I think raising the engine encourages it to happen so if you get it sorted then maybe you can tweak the setup and have it run even better.

Thanks Limecc.

It only happens when I'm solo, which is very rarely. I can count the number of times on one hand.

Limecc · 17 January 2022, 23:24

Quote:

Originally Posted by Steve509926

Thanks Limecc.

It only happens when I'm solo, which is very rarely. I can count the number of times on one hand.

Now that's funny. With mine it especially happened four up and it was quite violent bursting out. Also two up but I never noticed it solo.

Stepped rigid hulls deliberately introduce air for performance. If the SIB single bubble could be bled off into smaller ones, could have a good effect.

Fenlander · 17 January 2022, 23:58

That looks really interesting Steve... report from your on water trials much anticipated.

My experience with flat HP air floors is mostly with Zodiac and of the Zodiacs mostly with the models that have an HP keel under the HP floor. This had more of a blade shape so added to its higher pressure was less inclined to bend up in the middle than the LP sausage keel. However they didn't carry it as far back to the transom as seemed ideal hence now and again they still suffered the dreaded bubble.

Pic for interest.

Steve509926 · 18 January 2022, 08:18

Hi Fen, does any manufacturer still make a HP keel?

Fenlander · 18 January 2022, 09:20

I'm not sure. The Zodiac website only shows the sausage keel models... yet some dealers such as below still list the Fastroller with HP keel...

https://www.bhg-marine.co.uk/zodiac-...360-4330-p.asp

I think Zodiac were the only maker to have tried this design. The idea was sound but in my experience there were two issues.... The connecting hose between floor and keel was prone to leaks which let pressure out of both... and the keel often would not inflate at 90deg to the floor so making an offset keel line in the hull material.

Steve509926 · 18 January 2022, 23:37

Hi Fen, read your old threads/posts with regard to your FR360. Looks like you had a bit of bad luck and a few problems! Wonder why they stopped making it?

Fenlander · 19 January 2022, 00:34

Unknown to me at the time it was the period when Zodiac started to struggle and the dealer involved was a bit frustrated at the faults/returns they were having to push back to the factory. And despite it seeming a chunk of money around £1400 back then the "proper" Zodiac models like the Classic were nearer £2500. There was no doubt it was built down to a price.

In truth the Honwave I went onto for loads less money was better built. Having said that my Bombard is a Zodiac and is holding up well... 8yrs old this year.

TmMorris · 19 January 2022, 09:19

I pondered, last season, whether to make a pair of expanded foam inserts to sit either side of the sausage and I think this would end any air risk as well as stopping the boards from bending.

The initial thought was to mix up the liquid and pour it into black bags positioned on either side of the forward bilges akin to making fitted race seats and then, once set, cutting the tops to be flush with the underside of the air deck.

Steve509926 · 19 January 2022, 10:04

Hi Tim, think you'd need to start posting on the RIB forum if you went down that route

As I said to Limecc, I don't suffer from air bubbles under the hull that often, certainly not often enough to be a problem. I only came up with the idea because I needed to make a new airdeck/keel board and I'd read a few posts about air bubbles, prop slip and ply on top of airdecks.

Ill be routing it this afternoon and trying it for size in Redneck (of the rain keeps off!)

Steve509926 · 19 January 2022, 15:06

Routed, sanded and tried for size.

https://www.youtube.com/watch?v=mLxHdZe_kR0

Ready for epoxy coating.

Steve509926 · 06 February 2022, 20:28

I have found that semi retirement just means that those jobs for friends and family that I've managed to put off for years because of "work commitments" are now building up thick and fast! and I've not found an excuse to put them off that will work! Two kitchens and a bathroom since the turn of the year, give me work anyday!

So this weekend has been the first time I've managed to put aside to apply epoxy resin to my new airdeck/keelboard.
As advised, West System epoxy resin was duly ordered from ECF, how do they manage to deliver so quickly! impressed.

I thought I'd followed the instructions to the letter, but there is no denying, to my eyes the finish was nothing but sh.1t. The ply was covered and undoubtedly watertight, but it was lumpy and uneven, and even though it would never be seen by 99% of people, I would know it's not as it should be.
So what went wrong? I believe it's down to two things, firstly application by roller on such a small surface area isn't, in my opinion, the best way to apply epoxy. Secondly, I need to stop fiddling, trying to smooth out the imperfections I can see. I should let the epoxy "self level".
I left the imperfect epoxy dry for 24hrs, then sanded back all the lumps and bumps. I was impressed how much the epoxy had penetrated the ply, at least the first 2 layers. I warmed the resin and the hardner on the central heating radiator for an hour and heated the airdeck/keelboard with my better half's hairdryer. I then mixed the required amount of resin and hardner, but this time I poured the epoxy onto the new keelboard and brush applied it, then tipped it off, and hey presto a gleaming epoxy covered airdeck/keelboard. Just got the other side to do now.

Steve509926 · 09 February 2022, 14:20

I've finished applying epoxy to the new Airdeck keelboard and I'm pleased with the final finish.

I noted on a couple of vids about epoxy that some people finished off by coating with two pack polyurethane varnish, is this for esthetics or is there a need for it?

jeffstevens763@g · 09 February 2022, 20:47

Quote:

Originally Posted by Steve509926

I've finished applying epoxy to the new Airdeck keelboard and I'm pleased with the final finish.

I noted on a couple of vids about epoxy that some people finished off by coating with two pack polyurethane varnish, is this for esthetics or is there a need for it?

Some epoxies loose their shine even chalk Steve varnish keeps the shine

Steve509926 · 09 February 2022, 20:59

Quote:

Originally Posted by jeffstevens763@g

Some epoxies loose their shine even chalk Steve varnish keeps the shine

Thanks Jeff, as it's under the airdeck and only going to be seen by me chalky epoxy it will be

Just got to find time know to try it out on the water.

jeffstevens763@g · 09 February 2022, 22:03

Quote:

Originally Posted by Steve509926

Thanks Jeff, as it's under the airdeck and only going to be seen by me chalky epoxy it will be

Just got to find time know to try it out on the water.

Yea I would leave it bit of wax on it now and then will help, roll on the next trip too

Steve509926 · 05 March 2022, 20:12

Keelboard test date in the diary. This Tuesday 8th at Ulleswater, weather looks clm, dry, bright but bloody cold! Fingers crossed it works as planned otherwise its back to the drawing board.