another Barrel back launch

[Bob Abell 2Participant @bobabell2]

Hey, Phil

 

In that case………………..you could use silver paper and varnish it?

 

Bob………………..not my cup of tea though!

[Phil Winks 1Participant @philwinks1]

I thought about that Bob but most foil is a bit to light weight for the burnishing thats needed to ensure this stuff lays truly flat. basically after applying the tape you have to rub  it down with a smooth piece of wood I used a McDonalds stirring stick sanded smooth this tape is very like a product designed for this purpose called “Bare metal foil” available in  most metals and really does the business but heck its costly. about £8 for an A4 sized sheet so this tape works out cheaper I think at £5 for a 10m x 50mm roll. This tape isn’t coated I don’t think simply polished in the manufacturing procces so it will get laquered

[Paul TParticipant @pault84577]

Phil

 

Even loaded with motor and batteries mine will sit to high on the water and so I expect to use quite a chunk of ballast to get it down to the water line…hence the “all up weight” of 35 > 40kg. (the model was designed for a heavy 2 stroke engine and large petrol tank)

I am thinking of using water tanks with anti slosh plates so that I can add the extra weight at the lake side.

 

Paul

[Phil Winks 1Participant @philwinks1]

Still seems a lot of weight to me Paul. It may be I’m wrong on where the water line should be, I thought only just above the base, about 20%. of the sides (chine is it?)  or should it be deeper? Doesn’t look it on the pics i’ve seen. Mind you the cross section of yours will be a lot more than simply 11/2 times mine isn’t there some mathmatical rule of an inverse square which would make it something like 3 times the cross section of mine even so at my intended water line you’d only be looking at 30lbs to achieve that level on yours. maybe I’m displaying my lack of understanding of boat design or lousy maths  and there was me thinking this would be a relaxing hobby  never expected to get into advanced volume/area calcs well advanced for me 

 

Reading through all that it occurs to me that 20% up your hull sides will be 11/2 times again so thats another multiple making the required weight more in the region of 45lbs suddenly your boat looks less portly!!!!!! time to build a trailer for it mate or you’ll nevert get it to the lake  hope they’ve got a slipway or a crane

Edited By Phil Winks 1 on 12/05/2009 20:25:10

[Paul TParticipant @pault84577]

Hi Phil

 

I have a trailer to get my over sized models to the lake (and a 4×4 to tow it) my local water is at runcorn where there is a super slipway all I have to build is a launching trolley.

 

Paul

[Phil Winks 1Participant @philwinks1]

It gets worse seems my 1st guestimate of the waterline sect of my boat was a little on the low side having gone back to the cad drawings and got an accurate mearsure I was only just over 50% of whats actually there. so ignore the previous post and bear with me as I think out loud and tell me if this makes  sense.

 

The cross sectional area of mine is 4000cm^2 so for every cm I want it to sink into the water it will displace 4ltrs of water = to 4kg so given my sides are 10cm. to get 20% 0f the sides into the water I will need to displace 8ltrs of water = 8kg or 17lb + a bit to allow for the fact that its not truly flat bottomed. I will need ballast.

now multiply that by 1.5 with then 1.5 length and 1.5 depth Or 8X1.5X1.5X1.5 and I get 27kg so unless I’m barking up the wrong mathmatical tree (very possible) your boat will be a tad low in the water Paul from my questionable calcs you have a cross section of about 9000cm^2 so 35kg should sink you to about 4cm draft some how your boat looks light now sorry for rambling on but hopefully I got there in the end and now I need a cuppa as the grey matter is hurting

[ashley needhamParticipant @ashleyneedham69188]

Phil. Keep up the good work. Outstanding. This as what I call scratch building, at its best, using alternative materials and thinking outside the box!.  Excellent. Nothing more satisfying than finding something mundane or even odd to masquerade as , well, whatever you want, Try boat chandlers for cordage of all sizes, or larger cordage and using one of the strands from it.

 

B ob, I have used silver foil now and again,very effective, but have to watch that all the shiny bits are approx the same colour. No problems with the ally AND foil of course. 

 

I expect to see Paul carving lumps of Ally soon, eh???    Ashley

 

PS great intake !

 

PPS. weights, I have seen some claims of tonnes, or at least hundreds, nay, tens of pounds for models…..and find that these weights take some believing,,,,do bods ACTUALLY weigh their boats? or is it guestimate?

[ashley needhamParticipant @ashleyneedham69188]

NOT That I am disbelieving anyone, you understand, before I get a stroppy reply….Ashley

[Paul TParticipant @pault84577]

Good Morning Ashley

 

No need for a stroppy reply….you have expressed a very reasonable point of view.

In my case of building at such a large scale and not being in the best of health I need to know what the eventual weight of the model will be as I have to get it from the storage shed to the trailer…and then from the trailer to the launching trolley.

With some models I can split them in half (T.I.D. tug) but I could not do that with the barrel back so I designed it to have removable parts…such as motor / batteries.

I calculate the weights on the CAD system so they are fairly exact.

 

Phil

 

Glad you rechecked the drawings for the water line as I was beginning to doubt my calcs.

 

 

 

Paul

[Phil Winks 1Participant @philwinks1]

Ashley thanks and yes it makes for fun and amazing satisfaction about the weight In my case  yes I’ve physically weighed it and guessed at what the finall weight will be with the skin and veneer however it will be a guess at the end unless I can borrow some bathroom scales as the ones I have in my shed only go to 5kg. Now given that pauls boat displaces 8mm of water at the min from last nights calcs that means at present it weighs in the region of 15kg allowing for the V of the hull boy will you need some ballast Paul I think the water tank Idea is a sound one. they could be made with filler caps to look like refueling points and if you troll the model aircraft shops you will find a small electric pump that will fill and empty them for you. its what aero types use to fill their fuel tanks with they run at 12v.

[Phil Winks 1Participant @philwinks1]

Right now I’m stood waiting still for the finish birch ply to arrive and I’ve been promised it by Wednesday next week. so in the mean time, seeing as its to windy to fly my model aircraft, I’ve been tinkering with deck fittings and the rear hatch which is already skinned. the colour scheme I’ve plumped for is a mahogany hull above the water line and a pear wood deck. still unsure about caulk lines on the deck but will prob mask and paint them on prior to the final  varnish coat.

 

the fittings are simply laid on at the min. as you can see I’ve scrapped the original bollards and gone for a more authentic looking mooring ring

The stern has also got its veneer fitted and a coat of varnish.

Edited By Phil Winks 1 on 16/05/2009 12:59:39

[Phil Winks 1Participant @philwinks1]

A little more fiddling and I’ve got a windscreen and steering wheel

Lots of needle and riffler file work went into this

The ali on the windscreen needs the anodised protection polishing of but otherwise looks good to me.

[Phil Winks 1Participant @philwinks1]

just a little time in the shed this morning and again at lunch so I slapped another coat of varnish on the steerage hatch?? and I’m guessing this high build varnish is doing the trick! this is with 5 thinned coats only

I reckon by the time I’ve got another 8/10 coats on it’ll only need a couple of coats of the posh stuff

[Bob Abell 2Participant @bobabell2]

That`s looking the bizz now, Phil!………………………….I like the chrome edging too!

 

Phil and Paul…………………Will you both also include a 12″ rule on your next submissions, so that we can get an idea of size please?

 

Keep up the good work……………and don`t rush it!…………….this waiting game is great fun!

 

Bob

[Phil Winks 1Participant @philwinks1]

Cheers Bob and yes good point about the ruler! I will do.

[Paul TParticipant @pault84577]

Ok Bob, would you prefer imperial or metric.

[Bob Abell 2Participant @bobabell2]

I should think that a 12″ ruler is pretty clear!……………Boom! Boom!

 

Gotcha that time Sunshine!

 

Bob

[Phil Winks 1Participant @philwinks1]

 my pic of the steering wheel should meet with approval then Bob

[Paul TParticipant @pault84577]

Ok Bob I will use a clear 12in ruler…I have a kiddies plastic one somewhere in the craft room…but are you sure as it might not show up on the photos.

 

Paul

[Bob Abell 2Participant @bobabell2]

Well done, Phil, that`s the way to do it!

 

erm?…………………..looks a bit on the small side?

 

Bob with a discerning eye

[Phil Winks 1Participant @philwinks1]

Looks about right when I placed it in its final posn. Bob however if it looks small when its all fitted then a bigger one will be made simplzzzz  I do get the feeling that without the ski seat mine may look a little long for its beam but hey if it’s got a healthy performance who cares

[Bob Abell 2Participant @bobabell2]

OK then…………..Forget the ruler idea…………….let`s see the boats with the tranny alongside

 

Bob

[Paul TParticipant @pault84577]

Bob this is getting complicated …I haven’t got a transit but I have got a 4×4…..will that do?

 

Paul

[Bob Abell 2Participant @bobabell2]

OK………….We`ll make do with a rula?

 

Bob

[Paul TParticipant @pault84577]

Sorry for the bad jokes Bob but when you asked for photos with a 12″ ruler it just begged for a comic reply but couldn’t use the old classic as Colin would have been very upset……..or jealous.

 

But to get back to your request……. of course I will include a rule in my next batch of photos.

 

Paul

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