Thread: Help me choose a ~6m launch design?

No-one?

Spent today looking at a few designs.... I like the look of Arch Davis's Bay Pilot 18, too - although a bit on the small side, I may be able to stretch it, in consultation with Arch. I've built a Penobscot 14 of his before & his designs are nice.....

Anyone had any experience of Selway Fisher's desgins?

Hi Wombat

There is a Bundaberg Qld design Mark Bowdidge who is designing DIY light planning hulls for off shore work. He has a web site and has contributed in the forum but I can't remember his forum name.
Probably worth a look at his web site anyway.

John

Thanks John - I took a look, hull designs seem interesting, but none of the arrangements really suit what I'm after - the 5.2 is too small. The Sportzmaster hull looks to do the job, but I'd have to design a cabin arrangement to go on it......

Here is another design I'm looing at:

Boat plan details, Classic 19 Express (CX19), Power boats 17' to 20'

However, I'm looking at a cabin arrangement more like this:

Boat plan details, Harbor Master 19 (HM19), Power boats 17' to 20'

The above designs have flaws too, but I've included them as a good approximation of what I'm after.

Here is the Arch Davis Bay Pilot - a little small, but otherwise the general concept is what I'm after:

Wood Boat Plans, Wooden Boat Kits and Boat Designs - Arch Davis Design

Above all - even if the hull is a fairly modern design, I'm looking to give the cabin the appearance of a 1950's ish cruiser.

What about this one, Three Brothers by Ross Lillistone,, found at Bayside Wooden Boats?

Howdy,

Don't miss Australian David Payne's launches. They are designed for the type of power you are talking about and are the prettiest things. Unfortunately they are 6m

They also are very modern and quite light for their size with quite a light structural setup. It is also very flat across the transom which will give good speed and good stability at rest

You can see some info at the bottom of this page
Duck Flat Wooden Boats

.

The boat in the pic has a four stroke outboard which is a quiet and simple installation (and worth considering as a power option - its been moved further forward than the drawings so it hard to detect), but I think (but am not sure) that there is an inboard option. David Payne is one of my very favourite OZ designers. The hull was built by the shipwright's course at the Port Adelaide TAFE and finished at duckflat from the bare shell by the late Robin Badenoch.

best wishes
Michael Storer

First paragraph should have said "amount of power" - MIK

Originally Posted by Boatmik

Howdy,

Don't miss Australian David Payne's launches. They are designed for the type of power you are talking about and are the prettiest things. Unfortunately they are 6m

They also are very modern and quite light for their size with quite a light structural setup. It is also very flat across the transom which will give good speed and good stability at rest

best wishes
Michael Storer

Ummmm...... the title of the thread is that I WANT a 6m launch - so what is unfortunate about it :P.

As the OP states, I'm a fan of David Paynes, having built a couple of his boats before - my main concern was that I was under the impression that David's 6m launch is a semi-displacement boat, rather than a planing hull?

Originally Posted by Fair Dink

What about this one, Three Brothers by Ross Lillistone,, found at Bayside Wooden Boats?

Hmmmm, interesting.... My first impressions are 'to big'. 26ft is alot bigger than 6m (20ft) & I have to live with it on a trailer.... however, it's desgin criteria are very close to my specs..... But agin, it's really a semi-displacement boat..... Although it appears to have a decent turn of speed with 50hp..... And, I'm trying to keep the power requiremtn to no more than 60-70hp at the most, so it meets that criteria too....

Hm,mmmmmm....

Originally Posted by Wombat200

Ummmm...... the title of the thread is that I WANT a 6m launch - so what is unfortunate about it :P.

As the OP states, I'm a fan of David Paynes, having built a couple of his boats before - my main concern was that I was under the impression that David's 6m launch is a semi-displacement boat, rather than a planing hull?

Howdy!

I was looking on the net and while doing that I got confused about the length.

It may be suitable depending on the speeds you want to reach.

OK ... Planing, semiplaning and displacement. They are all definitions from the early days of boat design.

However there is no such thing as planing and no such thing as displacing. They describe a whole bunch of behaviours that describe a continuum. Just as a quick point ... if a boat is 100% planing then it cannot be displacing at all, which means it cannot be touching the water, which then means it cannot be planing.

This shows terms planing and displacing are mutually dependent - you can't have the one without the other. Popular writers have made them sound independent as if one disappears when you are doing the other. No boat is doing that.

So to get practical ...

What you are after is a boat that will be easily driven at sub planing speeds and you want to be able to go a bit faster if the combination of power, all up weight and hullshape will let you get up there.

The Payne boat is quite suitable. It doesn't have much immersed transom when going slow and really has a shape closer to many planing sailing dinghies.

Pure "planing" powerboat hullshapes have straight lines aft that make the transom deeply immersed making them very uneconomical at low speeds.

This boat doesn't have that feature.

At really high speeds under power a shape like the payne boat or most planing sailing dinghies start to misbehave because the curvature at the back end sucks the stern down deep into the water and the bow ends up sticking miles into the air.



I think the Payne boat is very suitable for lower speeds and will make a dash up a bit higher as well. You will get above "hull speed" with a 15hp outboard.

A pure displacement launch would be very happy around the 5.5knot mark but you wont' be able to go faster. At speeds lower than 4 knots it will be much more economical than the payne boat. The closer you get to 5.5knots the better the payne boat will perform in terms of economy.

The Payne boat will get you up to 8 knots or 12 knots or 15 knots with around a 10, 15 or 25hp outboard respectively and very approximately. But the more weight in the boat (junk) and the less benefit.

David would probably have a reasonable idea of what power would give expected speeds. One caution though ... heavier outboards (25,35,40hp) will affect the low speed ability of the boat.

It gets down to the type of speed you need. If 15 knots will do you this one could work. If you need 25 then it is very unsuitable.

Which of David's boats have you built?

Best wishes
Michael Storer

Hmmmmm, thanks for that Michael, it helps in terms of understanding the hull..... Most of the boats I have built / worked on in the past have been pure displacement launches - think boats built by Jack Pompie & other similar boats here in Vic.

My desired speed requirements are around the 20-30knot range, so sadly I don't think David's boat would be suitable - it meets every other requirement I have, really. I'll see if I can talk myself out of the speed, but as the main use of the boat will be shooting out into the bays snapper fishing, the speed really will be useful....... I guess I could always flick David an enail & get his thoughts & see if he could redeign the hull for me, but that might be a big ask.....

I have built 2 of David's yellowtail's for customers (both inboard power & no sail), and I have the plans for David's snapper boat sitting here, that I bought some ?8 years ago, that I never built.... Children, etc interfered with that & now my requirments have changed, although I'd love to build it one day as a recreational cruising boat..... make a great bay sailing boat.

Rob.

Hi Wombat

There is a Bundaberg Qld design Mark Bowdidge who is designing DIY light planning hulls for off shore work. He has a web site and has contributed in the forum but I can't remember his forum name.
Probably worth a look at his web site anyway.

John

G'day Rob,
Just thought I'd post a rendering of our latest new design coming out that is about to commence construction in the coming weeks.

Its called "The Black Label 27"

Its a trailerable strip plank composite design and it's acommodations downstairs are a large double berth/ hanging closet/ galley/ enclosed shower, toilet whilst upstaris we have the dinette which is opposite the helm station. It will have the option to be powered by and outboard or stern drive.

Still working on all the small details yet, which is why its not listed on our website yet. Anyway, here's a sneak preview

Regards
Mark
www.bowdidgemarinedesigns.com

Very nice Mark,look forward to seeing the plans.
Is this your next build?
What would the outboard hp range be?
Could a first time boat builder tackle the "Black Label 27"?
( fancy name that )

Thanks Mark - looks very impressive. Bit big, for me, really, though.....

Rob.

Thanks Stresslesski,
Actually this design was commissioned by a client in Maryborough QLD. He was originally looking at the Cruise Control 5.2, but wanted something larger for weekends or holidays of a week or more. So knowing what he wanted, he gave me a free hand to come up with a design to suit his needs.

As far as the Black Label 27 being built by a first timer...Nathan (the builder) has never built before. As with all our designs, there all targeted for the first time builder.

Glad you liked the name

Here's a couple more "snap shots"

Have a good one
regards
Mark
www.bowdidgemarinedesigns.com