Will 6" make a difference?

Okay, unless convinced otherwise, my next boat building project will be a Hartley 'Flareline' original plan is 14' 6" x 6' 9" and can be increased in length from there. I hope to use my 20HP Honda 4 stroke - (not after speed for this one).

If I was to give her another 6 inches to 15' x 6' 9" do you learned woodies believe this will have much impact on the efficiency of the 20Hp

Aberdeen - down south in Oz
__________________
"May your dreams of today
be the reality of tomorrow"

I have just finished building my first Hartley Boat - 3.3m (10' 9") x 1.5m (5')

http://www.hartley-boats.com/Husky%20by%20Glenn%20Angus.html

 

it looks like the chines fade back in at the transom. 6" probably won't hurt but you my hurt the designers feelings

 

Interesting thought, hadn't noticed that aspect, will take a closer look.
Re designer, that isn't a problem, the specs are recommended up to at least 10% more than basic design. I'm trying to work out if the extra 6" is worth it from a motor perspective.

Hartley boats have been around since the mid 1930's, Seems Colin Brookes was a co-designer with Sir Richard Hartley,.. Colin is still alive although most likely in his 80's plus.
http://www.hartley-boats.com/


Probably other than the Hartley Trailer Sailers I haven't found anything on their designs being used much over and around the States..... I was brought up as a lad with those boats, midlife crisis I guess has taken now hold I think!
Absolutely impressed with them, their tradition, feel etc.

Regards Glenn In Oz.

 

Lbr

Length to beam ratio.

It's all about stability really, and a lot of boats today seem to like to stick with a 3:1 length to beam ratio, meaning - that your selection of plan at 2.148:1 LBR is very narrow gutted - read inherrantly unstable by it's design.

Narrow gutted boats require less power to push thru the water, but the trade off is they are less stable than their wider beamed bretherin.

Ah - a good example was the Yamaha Southwind Banana boats & UB's (Utility boats) based on long Narrow traditional Japanes syle fishing boats.
They made a reasonable family fishing boat package because - requiring less Hp to power them meant they could be packaged with cheaper lower HP outboards - and the hulls could be well overpriced and a family could still afford one...

The tradeoff - was - if two out of 3 of the family went to one side at the same time...well it was almost capsize scenario...

So - why if you are going to build a boat, and knowing this would anyone in their right mind select a design that was well under an optimum LBR?

Yes - narrower (cheaper) sheets of ply can be used, and the plans can be designed around the availability of ply sheet widths, for minimal wasteage etc etc...but really - in todays day and age - is this still a valid reason to build a deficient design boat?

I mean - if built from sheets of alloy - those sheets can be manufactured to any width...at much the same cost - so why not get a better design to start with, and build it out of alloy (yourself) by mig welding a pre cut kit boat?

At least you will end up with something halfway decent as a boat with perhaps better resale value?

As Outboards get lighter and more powerfull, why would we restrict ourself to a design that is 30 - 40 years out of date and pass up all those benefits of technology so freely available today...

Stability is supposedly important in a boat for safety reasons so why compromise in that respect if you don't have to?

Sorry to shoot holes in what you've selected - but you wouldn't catch me dead riding in it - in a puddle down the street let alone a river, estuary or god forbid - open waters.

Length to Beam ratio - Vessel stability - why not google search the subject and then re-evaluate your selection of plan...is my advice for what it's worth.

Cheers & good luck!

 

Very well said!

 

If you increased the station spacing by the amount necessary to gain the extra length,it would probably make no real difference.It would probably give no great advantage either.

 

Do not post when tired!!!

Sheesh - I should be hung drawn & quartered....my only excuse was it was the wee early hours and I shoulda been in bed!

In fact - at a 2:1 length beam ratio - the design is in fact 1/3 MORE stable than it's 3:1 LBR cousin I described...

So basically ignore all I said above - tis all crapola and should be seen for what it is - dead wrong!

Sometimes I scare even me with what i know - and what I think i know - and sadly - I even convince myself sometimes that what I'm writing is correct - when upon re reading it with fresh eyes - I realise, I was sprouting garbage!

Sooo - nice plan ya got there - er - good luck with it!

Cheers!

P.s. (Surprised a few of the qualified people here didn't pick up on my error!...and shoot me down before I managed to shoot myself in the foot!)

 

Hey Trouty,
That's okay, have been known to do things myself like that and not only in the wee small hours.
Just got home from work, logged in and about to give you a tirade, well actually not a real serve, just a small stir.... I picked up your slight error when I read your reply...... and realised things were not quite as they should be.

I do agree with your original sentiments, albeit in relation to the banana boat types, but with an approx 48% LBR for this design I was rather surprised with your summary your calculation of 2.148:1 LBR is very narrow gutted did have me a little perplexed, confused none the less. Hence why I was going to reply. After all the avg boat as you quoted had a 3:1.

But it is good you picked up the error of your ways not every man would admit that... so good on ya to get back...... and the other qualified people you mentioned, well now you can stir them

So you into boat building, fishing, or both?

 

Hi Bruce, for info maybe a quick read of the last response re LBR from Trouty

Glenn in Adelaide

 

Hi Aberdeen

Both is the honest answer.

I Charter fish, (poorly) for a living (going broke fast), but just love boats and boat building / design. Have built a boat myself and my Father built boats when I was a kid.

I like all things about boats (except sail boats!)

I just like boats - dunno why..I just like 'em - heck I enjoy cruising the canals looking at other peoples boats, to see what I do or do not like about their design / shape / lines etc...

Dunno what it is about boats that suckers me in - I love my own boat, but still like to look at other boats...(bit like the missus really - love her to death but still like looking at "other wimmin")

I also seem to find I usually like people who like boats! (With the exception of that panty wad Guillermo...but the less said 'bout that the better!)

Cheers!

 

me too - although it has been about 35+ yrs

Suddenly got the urge, maybe mid-life crisis - to build a boat.
Now that is done I'm going to build a bigger one, then a bigger one again....

Just trying to work out what will be the best timber for the frames of my new, soon to start, 15 footer......

Glenn in Adelaide.

 

Six inches will make no real difference in a power boat or human powered boat. If anything it will give a slight improvement in speed.

The amounts that you are talking about is tiny in the scheme of things - I am sure you have your reasons, but as wet feet says it will make no real difference.
Even a 10 to 15 percent change will not make much difference. More than that and you may have to look at changing the structure.

Space out the frames and reloft the stem - ie multiply all longitudinal measurements by the required percentage.

DON'T shrink or expand a sailing boat though unless you know exactly what you are doing!!! As one customer did with one of my designs putting the whole thing out of whack.

Boatmik
my boaat pages

 

6"

Hi BoatMik
Thank you for your comments. I assume you are the one and only Storer boat designer? Have heard a lot of positives about your designs, haven't experienced any first hand though (sorry about that) and didn't realise you are a local lad.

I have virtually committed myself to building a Hartley 'Flareline' 15 next as an interim project before hoping to do something closer to the 20+ feet for retirement purposes in about 6 years. Guess I had better start taking notes on what you have on offer!

Thought about sail but totally ignorant on what's involved, looks like it can be hard work, especially if one is on their own in a big one?

As for the thoughts on 6"more: basically I have a trailer already that is set up for a 15' - hate to have wasted capacity and as the plans are flexible from 14'6" to about another foot or so I thought "why not?"

Will move over to your website and take a peek.

Regards
Glenn down at Woodcroft

 

6"

BOATMIK
One little question you might be able to help me with please?

Trying to decide what timber to use for the frames (yes I know they went out years ago) of my new 15 footer. Lots of varieties of wood but which one? Will probably use Hoop ply for hull.

Ta
Glenn

 

Hi Glenn,

The only people who have something good to say about me are those I have paid in advance!

As far as wood selection goes, a few years ago I would have said Oregon (Douglas Fir to those from the North), but its price has jumped up and up, so unless you happen across some good quality salvage stuff I would go for frames out of hoop pine as well.

Hoop for frames is not as nice as the fir mainly because it is plantation grown rather quickly whereas the oregon was looted old growth forest which was hugely superior.

But the hoop is certainly adequate. Particularly for an epoxy glued boat whih is more structurally efficient than boats built the old way (that comment might fire up a bit of excitement in this thread!)

I would also strongly suggest leaving the fastenings out - saves money and doesn't weaken the boat. (another way to fire up a bit of excitement on this thread)

There are other timbers of medium density which glue well (not oily or waxy) also available, but I would get a cubic metre price on the Hoop Pine and see if you could get something cheaper that was equally free from knots and defects. Or you could just go with the Hoop. Others may have some suggestions as to what is available in South Australia

Best Regards
Michael Storer
my boat pages