F85SR Concept Boat

I just had another thought Phill, If the lifting foils don't work, Just put extra lead in the stern(you could always carry the bottles of rum back there). The floats is looking really good.

Richard,
What a good idea, with a bit of plumbing we could run rum ballast instead of water ballast.

Something I first tried years back and is proving to be very useful on this build is using a scraper
in some circumstances that would otherwise involve sanding.
One example would be if you accidentally get a run of resin over a surface of paint, timber or even foam. Sanding that run away will not only take quite a bit of effort but it also damages the surface around the run.

On the other hand a scraper with a nice sharp tungsten blade and light pressure will remove the run with
little or no damage to the surrounding area (depending on how careful you are.)

I had some runs on the foam which I easily removed with the scraper without marking the foam and I also
used the scraper to taper the edge of the glass in preparation for the overlap when the other side is
glassed. It can be an amazingly handy tool and can save quite a bit of elbow grease.

Below is a pic of the scraper that I'm using.

Vacuuming the external laminate for the lifting foil side of the float posed the problem of sealing for a vacuum without the risk of crushing the case. I've added some pics as per below.

Before the glass was wet out the openning for the case was cut in it. After the perforated film, peel ply and wadding were also cut for the case openning and packing tape was used to make sure no parts of these layers could interfere with a vacuum seal around the case openning.

The pic below just shows the vacuum has been applied (again getting 25 inches or 12 lbs per sq inch). You can see dark patches where the wadding is taking up some resin.

I've been using household irrigation supplies for the vacuum plumbing. Here you can see a hose (that I punched small holes in) wrapped in wadding distributing the vacuum along the length of the hull.

Not only did I seal around the case opennings I also put a breather hole in the film covering the case openning as an added precaution to make sure I did not pull a vacuum on the case. The cases are very strong but still not worth risking crushing them.

All cured, peeling away the layers to see the results.

The plan today was to laminate the stbd side of the stbd float.
I had organised a friend to come along and lend a hand.
He told another friend who is also building a boat and they both turned up.
All went extremely well and it is currently under a vacuum of 26 inches = 12.77lpounds per sq inch.
Below are some pics of the hull side under vacuum.

Finished laminating the outside of the floats today.
The last side is currently under vacuum and due to the cold temp I will run the vacuum most of the night.
It is currently pulling 25 inches once again. I'm very happy with the way they are turning out, they seem very stiff
and have a ring to them when you tap them.
I'll take some pics of the two floats together over the next day or two.

I haven't got around to taking the pics of the hulls together but i have a few other pics that I'll post as I find the time.
Once the outside has been laminated I need to gain access to do some work on the inside.
This is simply done by cutting holes in the deck. Doing the work and then repairing the hole.

The pic below shows a hole I cut in the foredeck to install a compression strut and glass the inside seems.

In order to repair the hole a glass plate is made using the deck as a mould. The plate is then glued to the section of deck.

With the floats suspended from above i thought of a novel way of clamping the glue joint when making the repair.

Below are a couple of other pics or the Transom an bow.

I've installed a transom strong enough to take rudders and stay in one piece if the rudder hits an object.

The transom is in two parts allowing easy access to ensure the part that takes the rudder is well glassed in. Above is a pic of the final shape.

Below is a shot of the bow. Once faired and painted you probably won't even notice the two small holes that provide a strong point to attach the spinnaker pole brace.

Thanks Phill!

You mentioned

cold

. I thought it was heating up as summer approaced?

Rolf,
Summer is approaching but it's not that warm just yet.
I went for a short 40km ride today and it was only 12 deg C.

Speaking of cold you reminded me of a little experiment I thought I'd try a week or so back. I tried making a glass tube over a solid aluminum mandrel for a part of my Carbon Chain plate.
Rather than coating the mandrel in candle wax that I'd melt later to release I got this bright idea of freezing the final tube and mandrel to shrink the mandrel for release.
Just in case your thinking of trying something like this don't bother, go with the candle wax. I did finally get the glass tube and mandrel apart undamaged but it took a winch and some snap straps to do it. The glass tube has an inside dia of 12.5mm an outside dia of 18.5mm, 190mm long and weighs 47gms. and it took a 1metre length of 200gm plain weave glass to make.

Below is just a couple of pics of my setup. I spun the mandrel with the drill slowly to wrap the glass around it and then quickly while gripping the glass to compact the layup and remove excess resin. Then applied the peel ply and finally tape.

Once cured the peel ply and tape is removed. This is a good time to sand it if required, while the drill can still spin it.

Bump

For over a week now I've been getting a

Critical Error

when trying to access the photo album so I'm unable to upload more pics. My carbon chain plates are built and installed and I'm very happy with the result. It's time to put a finish on the outside of the floats.
So I've diverted to excavating under my front verandah and will put in a 20 plus metre long path 1600mm wide and brick retaining wall where I can store the floats end to end and work on putting a finish on them while working on the beams and main hull. Having them out of the way like this will allow me to work on the finish at my leisure and I can keep at it until it is spot on.
This excavation is taking a while and I can't wait to get back to working on the boat.

BTW:- Mark Hastings is just about finish machining the folding mech on his CNC machine and it is really top notch work. I can't post a pic of it on catsailor with the

critical error problem

but he did post one on Multihull Sailing Anarchy. If the Catsailor photo album starts working I'll stick a pic there.

Take care with your back when working under your veranda! <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />

Phill, very interesting project... what are the beams like? I am needing some F-24 beams and wondering if they are the same dimensions?

Scott,
The best bet would be to shoot an email to Ian Farrier.
There is a slight difference between the F85 and F82 beams but I have no idea how that compares to the F24. A question to the designer would most likely get you the info that you need.
Regards,
Phill

Hi Phil
Thanks for putting in the effort to do the web page for the world to see.
I am considering a F85SR Build in Western Australia.
What size vac pump are you using?
Did you compile a composite purchase list? I am trying to get a handle on the cost for a simple F85SR but mostly to determine what I need to spend to get started?
It is great to see you weight data for the areas where you show how much resin used and how much saved by the bagging.

What epoxy are you using? Supplier?

What head height do you think is the minimum? I dont think it is going to fit my garage so I am considering a temp shed.
Any other people considering a build in western Australia?
Thanks
David

David,
I'll answer below:-

>I am considering a F85SR Build in Western Australia.
>What size vac pump are you using?

The pump I'm using has a 1hp motor. I don't have any other info as it was a gift from a friend.

>Did you compile a composite purchase list?
A comprehensive list comes with the plans so I used that.

>I am trying to get a handle on the cost for a simple F85SR >but mostly to determine what I need to spend to get started?

That depends if you want to buy all your materials first or just a bit at a time. I bought all the resin, glass, foam, uni carbon, vacuum consumeables (release film, vac film and absorption fabric) as well resin additives (filler, glue mix etc). Basically all the composite materials that I need to make the floats, beams and main hull for around $14,000

I had to shop around to get it at this price but if you do decide to build I'm happy to share my supplier info offline.
That would at least give you something to start working from.

>What epoxy are you using? Supplier?

Over the years I've built up a rather strong allergy to most brands of epoxy. So when I went looking for epoxy I wanted something that was not only a good quality but also one that would not affect me too badly. I ended up buying my epoxy from Gurit. So I'm using Ampreg 21. I really like this epoxy but it is one of the more expensive. If cost is an issue I can tell you of other epoxies that are cheaper. The extra cost was worth it to me because of my allergy.

>What head height do you think is the minimum?

This is also specified in the plans. Farrier leaves nothing out. The height to be able to join the main hull is 2750mm. But this is on a strong back with legs. (The legs specified are there to make the work easy on your back. Not too much bending.)
I have 2700mm and will cut the legs down on the strong back when I want to join the main hull.

I hope that info is of some help.

Regards,
Phill

Thanks Phil
This gives me a some things to think about.
I will research about Ampreg 21, I have mostly used West System (by the 4 lt pack) Work height is an issue for me at home for the hull joining.

I have had a win on the home front and the

Honey do list

before I start is less than a months work <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />

Regards
David

David the WA agent for SP_gurit is Summit Chemicals in Bibra Lake, they should be able to help you with Ampreg and other associated materials. If you talk to Chris at Boating Hardware and he will probably be able to point you to a Vacuum Pump you could borrow and help sort ou your other needs.

David,
The height issue will most likely not raise its head until joining the main hull. I know one F85SR builder who does not have legs on his strong back from the start which would save between 250- 300mm.
Please let me know how it goes if you do decide to build I'd like to keep in touch. I'm talking to other F85SR builders and we try to help each other.
Also the plans are quite extensive. When you first get them many take a back step because of the detail that Farrier includes.
His name depends on builders like us building to a certain standard and so he leaves nothing out and the detail really helps with the build. All you have to do is follow the plans and tick the boxes as you go.
If you decide to build get the plans as soon as you can so you have time to digest the detail.

Good luck,
Regards,
Phill

Hello David. For building my F-85SR I am using 2 pumps, both 3/4 hp. Theoreticaly they can handle 226 Liters/minute each. The exra pump helps if you have a small leak, so you still can have a reasonable pressure. One of the pumps runs via a pressure switch. It switches off when a pressure of around 0.7 bar / 21"HG is reached. My pumps are of chinese manufacture and use quite a bit of oil, to the point that I have made exhaust tubing to lead the oil outside. But it works well.

Phill is a great source of information. I can't match his building pace but it is nice to exchange information and profit from his extensive building experience and knowledge.

As to building costs: Some builders have gone to cheaper foams to keep the cost down. My advise is to not go this route, but use the best there is: Corecell M ( IMHO ... <img src="<>/whistle.gif" alt="whistle" title="whistle" height="15" width="15" /> ) I spoke to several F-82 builders here in the netherlands who went this route, but in hindsight they now say they would have done otherwise.

Regards
Nico

Thanks Phil and Nico
Great to find some builders of the F85SR Online.
I have sent off for a set of plans. My list of things before I decide is getting shorter. (Short enough to buy the plans)

Cant wait to see how the hydrofoils angle of attack is set. The ways I could think of doing this would not be easy..

Thanks for the Corecell M comment, I will do some more reading on the subject as I know little about foam core.
Did other people have delamination issues? Weight issues?

I have done smaller things with honeycomb composites with carbon fibre and got thousands of pinholes that had to be sealed. Only other foam core work I have done was all specified by someone else using vacuum bag and high pressure hot water on the outside.. Far too much work to do for fun!
I know you are vac bagging, did you do a time/cost benefit of hand layup?
Initial thoughts are to do lots of the small parts first rather than the floats due to limited space. What do you think?
I have a homebuilt CNC machine, MechMate, that I need to sort Y axis alignment on (it is about a mm in a m out of square on X versus Y before I can consider cutting forms and parts (Or would you consider this accuracy adequate?

I am expecting this to be a five year build.

Cheers
David

Ian gets you to make the bulkheads first so that is a good warm-up on vac bagging.
Most of the time, the build only involves one layer of laminate so it is quite easy to do a decent hand lay-up without vac bagging, especially if you use epoxy. Use peel-ply on everything though.
Whilst your vac-bagged bulkheads will have a nice laminate finish, I think that the main benefit of bagging them is that they will be absolutely flat and true.

David,
There is an F85SR builder who lives only a few kms from me who is building without vacuum bagging and many F82s and other size F-boats have been built without vacuum. I would not be surprised if more were built without vacuum than with vacuum. There is no doubt about it, it's quicker and cheaper to not vacuum.

I'm vacuuming because I wanted to build the best boat that I could build and over the years I've acquired 3 vacuum pumps.

As far as accuracy of your CNC Mark Hastings did our CNC work. He designed and built his own machine and does excellent work. I expect he would be a good person to answer your CNC question. I'll drop him a line and see what he has to say.

Regards,
Phill

Welkom to the club <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />

Bagging a floathalf is a bit more complicated than bagging the bulkheads, I find. It's not really a black art, but there are a few things that have to be done exactly right. I did not compare costs. Hand layup is cheaper and faster. Bagging is stronger and lighter. I chose to go for the latter ( and also because I thought it would be fun ) When bagging, the layup is a little bit less critical. If there are a few air bubbles, they will be sucked out. I still try to get a good layup though, just in case the vacuum goes bust.... For hand layup, a wet layup seems to be the best method. For bagging, I don't think that's neccessary and a dry layup is easier.

Doing the small parts first is a good idea. As for the floats, these are my lessons learned:

- use a foam toaster/oven to heat the foam. 100C seems to be ideal. A bit lower temperature works as well, but you will have to apply a heatgun in the tight radii of the deck. If you do this the foam will fit in the mold with minimal stress.
- To avoid leakage along the screws it is important that they don't penetrate more than 7mm into the foam. Side effect is that the holding power of the screws in minimal. That is why the pre-heating of the foam is so important.
- I chose to rebate the foam strips. Advantage is that you won't have to cut the foam to size and the bog can't sag through. When bogging the seams, I do that in 2 steps. The first step is with a thin bog, that I work into the seam with a small popsicle. Before that is completely hardened I add a second layer with thicker bog to fair the joint. This assures a leak free joint between the strips.
- Tacky tape and wet epoxy don't mix. I take the easy road: I use two layers, one on the bag, and one pre-applied on the foam edge that that is left sticking out of the mold. You can also protect the foam edge with tape. The tacky tape doesn't stick to foam very well, so I apply a very thin layer of bog on the edge.

I'd try to get the mistake out, if it's not too dificult. My CNC router has the same setup as the MechMate. Because I have a rack and pinion drive, my machine is only accurate within 1 mm ( the X- axis is a bit better than the Y- axis. I should have gone for 2 stepmotors on that axis too in hindsight ) This is enough though.

That's what I expect as well. 5 - 6 years.
Regards
Nico

ps: feel free to contact me on info at nyker dot nl. I've learned a lot in the last year, not in the least because Phill was so kind to share his experience.

Hi David

The Mechmates are a really good looking design and I would have gone that way if I hadn't got most of my build out of decommissioned gear at work which dictated the design by the components I had.

Being dual slave drive rack and pinion (thats right?) dialing out any skew should be a breeze. What I would suggest you do is put two thin DF of other scrap sheets down an cut thru both a big square. Then flip the boards face to face along the X axis this will double your skew error that you can measure between the two pieces and use this value to rack the gantry. Loosen the gantry to drive sides and adjust your home sensors accordingly.

Now rotate the top test piece 90 degrees and compare the X and Y dimension and adjust you tuning as needed.

But first...check that everything on the machine and drive are snug with minimal backlash etc.

Probably telling you how to suck eggs.. I 'm sure if you built the machine you can tweak it to get it right and probably to within a fraction of a mm accurate. Just don't loose sight of what it is your cutting and the processes afterwards to the part .. lots of small variances disappear in the end product but getting stuff square is importatnt because of the doubling effect when you flip parts (think forms and mirrored sides of the floats)

PM me if you need any help.
Cheers
Mark

Thanks for the input guys.
The Mech mate has a slave on the x axis with two rack and pinion stepper motors. I used the cutting of two boards and turning one over technique to determine trueness of the straight cuts (within0.2mm) and squareness (approx 0.8mm per m out but plus or minus half depending where it is switched on. I can adjust most of that out, just take another couple of days...as it will require reseting the Z squareness and resurfacing the table.

The way I am thinking if I cut all formblocks from the same side no issue with fairness and the part must move a mm, anyway should do the correction in a couple of weeks.
It is very hard to prove these home make machines are better than a mm accuracy in their length. When I started the testing they were about five percent out because the chinese gearboxes were not the ratio advertised, That took a while to prove...

Thanks for the hints about working with quality foam and the heat it can handle. It is so much easier to follow than lead.

Plans should be here in a couple of weeks so on with the

honey do list

Cheers
David

David,
Welcome to the F85SR club. I hope you enjoy the building as much as I am.
On another topic I still can't post pics on the catsailor photo albumn so can't show anymore pics of my build. I sent a message to Rick a while back and he said he will look into the problem.

Currently I'm sanding the folding Mech that Mark Hastings has made for me using his CNC machine. He has done a wonderful job so I'm removing the machine marks to make it perfect before it gets anodized.

I'm using 180, and 600 wet and dry. The 180 is used dry. It is quite surprising when I brush off the dust that builds up with my bare hand it takes half a dozen strokes of the 180 before the oil deposited by my fingers is removed. I can feel the 180 slide back and forth before it starts to cut again.
To me this illustrates the folly of touching sanded glass when you are about to bond something to it. No wonder Farrier is so adamant that you must not touch the areas the beams are to bond to in the floats after they are prepared.

I was quite surprised how such a small amount of contact can make such a big difference.This project is not only enjoyable it is also full of interesting observations.

Regards,
Phill

Phil, did you make the daggerboard cases yourself or get them from Ian?

Also I'm thinking about a F85 build, how much would you want for the frames and what are they made out of??

ed,
Cases came from Farrier Marine. When you see them you will realise they are really very good value.
Frames are made from MDF sealed with clear lacquer on the faces and 2 coats of epoxy along the edges.
Where are you located? I'm on the NSW Central Coast .
If you are not too far away you can send me a PM with your number we can talk about frames and any general questions that you may have re building etc.