Idealist

Dreamwakes

Got anything done on the decks yet?
Can´t wait to see my hullshape Mk.VIII with that typical "Bank Pop IV" deckshapes!

Idealist

Morspeed

Looking forward to it myself Idealist....but I will be building a set of hulls first, then building the decks onto the new hulls, is the only way to get a perfect match...(for me anyway).

Dreamwakes 

cytek

Gary

I was meaning for the rigs themselves.
I had priced a wing that was around 60mm at the base tapering to around 40mm from above the forestay. It was to have been hotwire cut from polystyrene, and then glassed over.

Marty

Morspeed

Hey Cytek. yea, I really like that idea, I had been wondering about this idea for a while, since I was initially planning to build my own spars,

My main concern in this idea was you would really need a rotating mast to get the most out of this which is another series of problems needing solving, I think if I went down this road I would build my own foils from scratch. For now, I will stick with a traditional rig and mylar sails for the first two I build.

cheers
Dreamwakes

Morspeed

Over the last ten days the hulls have been at the ugly stage of proceedings, since the first coat of primer I have blocked the hulls back with 80 gritand then put a very thin screed of epoxy fairingcream over them, then blocked back again with 80 and then 150 grit paper.

Finally today sprayed a heavy coat of my very good friend "Duratec surfacing primer", here the pics below show hulls ready forsome pin hole filling and a 180 grit block back.

Morspeed

Also built a handful of plugs to be used asmini radio boxes- these will house the battery packs and receivers in their own individual boxes.

Built these out of scrap balsa, glued them down to a sheet of 16mm mdfand sprayed today with duratec.

Morspeed

I am gonna build a few experimental foils for float hulls, does anyone out there have any info on shape/ curve I should be building. I can only find pics on Orma 60's that are taken from angles that make it hard to determine the size/ shape I should be building

Cheers........gary

TBK

Gary

Ive been doing a little bit of research on this as well as I believe that the boats performance can be improved with the aid of some foils on the floats. There has been a fair bit of experimentation done by guys in Europe. There is some video footage of a tri at the Gosport club in Britian which has curved foils on the floats similar to a scaled down ORMA boat. It really helps to keep the boat level when hit by a gust. If you go to tghe German website you can see what they are currently playing with. Ernst provided me a link and I'll see if I can dig it up. Here are some pics of things I have found.

Morspeed

Hi TBK, cheers for the pics/ info, this attached pic is about the best I can find which shows the foil in action, this is what I want to build, it makes alot of sense to me to provide a little lift in the leeward float . I have been told that the extra drag will cost boatspeed, of course this would be true but surely the advantage of being able to maintain a more stable hull with less bow burying attitude would give a overall higher average speed around a course..anyway , I will experiment and see what happens, I only wish I could find some detailed crosssectional drawings to give me a better idea from outset of the profile I need to create.

TBK

Gary

Here's a way to picture what it might look like. Take an small thin airplane wing - flat bottom, diherdral (round) top - stuff it inside the float hull facing downward at about 38-40 degrees from the horizontal and ta da you got a lift inducing foil. If it was really that simple we'd all have foilers. Most working models are a combination of aeronautic and hydrodynamic design plus a lot of trial and error. I am also going to experiment with foils on the float hulls. I'm going to start by making a few "test" shapes that can bolt up underneath the forward crossbeams. That will allow me to see what works and what doesn't without the need to build specific floats or doing any modifications to my existing boats. I plan to try a mix of both straight foils at various angles/lengths and then try some curved shapes similar to the type you see on the ORMA tri's. Of course all this isn't going to start until my last boat is finished and sailing, which should be in a couple more days.

TBK

Idealist

Dreamwakes

How are the plugs/moulds coming along?

Idealist

Morspeed

Things are coming along nicely Idealist, should be putting final coat on plugs in a few days, will post an update next week, where is your build at now??.

Dreamwakes

Idealist

Dreamwakes

I started something VERY different in between -
just building beautiful slim hulls gets obviously boring after some time -...- Hahaha!

But the Mk.VIII foam plug stands right beside -...-

That will become a really mean Pirategaleon.

Hull:
length: 138 cm
width: 32 cm
height: 45 cm

Overall dimensions:
length: 160 cm
width: 62 cm
heigth: 120 cm

Fully rc-equipped, weight ready-to-sail approx. 30 kg

Idealist

Morspeed

Idealist, as i said thats a fairly impressive project you've taken on, I will be watching your build log with interest.


TBK, I have found a excellent source of foil assist info via a few of our fellow builders who very kindly pointed me in the right direction.

First off is a pic attached of the foil from the new Banque pop 40mt tri- secondly this link , http://forums.sailinganarchy.com/index.php?showtopic=82807&st=0&start=0[/url]
is brilliant and up to date...I had to register to veiw the attached pics..well worth the effort. Sure is a lot of pro's and cons to foil assist MINI 40's but I cannot help but think this multi development has a very long way to go yet, so at this point I am definately going to experiment with foil ideas.

Thirdly this link, has an enormous amount of sound techical information on foils, http://www.boatdesign.net/forums/sai...sign-2447.html

By the way.. build update; I am putting another coat of primer on my hulls tommorrow, have cut transoms back to desired angles and faired up gunnel line, also built a couple of cradles for the hulls by laminating a layer of glass over plugs...will post a few pics in a few days.

Enjoy

Gary

TBK

Gary

Thanks for the pictures and links. The Bank pop foil is what I have seen used on some other models with reasonable success. It didn't result in full "flying" but it did keep the bows up and the boat more stable especially in gusts. I finally got the new carbon fober Nightmare MKVII on its maiden voyage yesterday. I made a few changes to it from its glass sister. I added more mast rake and a small inverted wing bottom on the rudder. The performance was markedly better. The boat had very little tendency to nose over on the gusts, if fact the more the boat powered up the better it performed. Although the wind was light for the test, less than 10 knots I was more than pleased with the result. I'll post the video on youtube tonight and send you the link. I'll also put some photos of the finished boat rigged with details on the rudder wing on my nightmare build log tonight. Are you planning to use a foil design similar to the Bank Pop? If so are you going to make foil box inserts in the float hulls to install them or are you just going to "bolt them up" to the sides for now?

TBK

Morspeed

Hi TBK, really reading about mixed results with float mounted sail assist foils, But I see myself building small curved foils so the windward one will not drag.

Seems you need a stable breeze for these foils to work so ideally they would be removable for days when conditions are shifty, therefore it stands I would look at putting carbon tubes in float hulls to thru mount stainless rods fixed into foils. This means they could be removable and the hull holes patched with decal when not in use...also maybe very slightly oversize tubes in hull would mean for allowing a little adjustment of foil inclination.

Got my camera software working again so look out for a picture update.

Gary

Dreamin Hemi

Looking forward to seeing this progress.

martno1fan

Came across this you might be interested in it.
Mart
[link]http://my.opera.com/BMMApics/blog/[/link]

nice video
[link]http://www.youtube.com/watch?v=H9DXlhlRsxI[/link]
cat
[link]http://www.youtube.com/watch?v=Ti9ggu_q4qw&feature=related[/link]

Morspeed

Well, its been two weeks since I lasted posted any pics so here we go.

Since the heavy coat of duratec sprayed two weeks ago I have been busy fairing,filling the hulls. Shaping the bows to a final point. Cutting the transoms to the desired angle and slicing off the stern and bow frames at deck level. Finally putting a little shape into the gunnel line.

I will slice of the bows in a week or so ( to allow for bow bumper) but wanted the full length of final hulls so I could ensure they were within class rules and both hulls were perfectly matched in length. This also meant I could get a true feel for how the bow bumpers will shape up when fitted eventually.

As for the transom cut, this was fairly easy, with plenty work from a hot glue gun I glued in a new mdf transom at the desired angle inside the old transom. Then with the dremel cut off saw, sliced off the old transom. Then glued a balsa cover on the outside of new transom which covered and secured the endgrains of hull planking.

Morspeed

Then, because I need a temporary cradle for the hulls while I work on cutting off all frames next week and also fitting a mould flange...I did this..

Wrapped hulls in clingfilm, laid over 3 layers of 9oz cloth on fore and aft sections on both hulls, brushed on a little epoxy, once cured , cut MDF frames to fit over the glass cloth, alinged with a level and used plenty of hot glue to secure the cradles to glass and to bond 4 corners of cradle box together. This whole deal holds the hulls very securely without the danger of scoring or leaving dents in the hull balsa. Ok so this was very quick to throw together and maybe a bit of an overkill for a temporary cradle...but the hulls are at the point now where they are incredibly fair , one scratch means more bog, more sanding and more primer.

Morspeed

Yesterday, mixed a 30/70 ratio of Duratec clear high gloss and duratec surfacing primer, sprayed several coats and here she is...finally a little gloss, everything is looking ok, a few areas where a little filler is needed but that was expected.

Next thing I will block back with 280/320 dry, slice off the bows (around 18mm) and give a final duratec coat in around 7 days. Progress has slowed slightly as I have been roped into building a epoxy carbon bonnet for a mates rally car and this has taken a little of my free time. This project will be over in a week or so.

Enjoy...

Morspeed

Thank you Mart, excellent links and vids..most enjoyable..interesting to see a foil assist Tri performing. Surprised at how small the BMMA is in Pomgolia, kinda expected to see a bigger multi following up your way??.

TBK

Gary

Great work. The plugs look impeccable and should result in a awesome set of female moulds. I know how much effort it takes to get to this point. Keep it up and I look forward to watching you progress this further towards the female moulds. I am considering doing the same with my male plugs, once I follow what you are doing. I'm also about to start on an RG65 build following Siri's/Ernst's plans so I might try this approach with that build.

TBK

martno1fan

Yea your not wrong mate id think there would be more interest,mind you speaking for myself ive planend on building one for a cpl of years and just never find the time,maybe if there were more ready built hulls for the guys to build them from they would take off?.Might be something i can help with as im a glass hull builder,mainly gas boats but id love to have a go at some multi hulls.Just that little thing called time lol,im not that clued up on rigging sail boats either to be honest.Glad you enjoyed the videos,your plugs look awesome ,top work i know how hard it is to get to that stage and that quality .
Mart

Idealist

Dreamwakes

I´m still here and watching!

Keep the pics of your progess coming, please.

Idealist