Evolving 'Polly Wee'

[BrianP]

Went through these issues with Raid.

If the top of the bags/tanks are below the water level outside the hull, then simply vent the tank and it will fill. Close the vent and bailer/valve when full. Open both on trailer, or pump out.

If the top of the bags/tanks is above outside water level, as it usually is, then once the tanks are full to outside water level then just fill up to top with a bucket which you will have around for bailing anyway.

All the electric pumps and connected pipes were just too complicated.

We had the water ballast too high in the hull sides which drove her over in a capsized position. That high buoyancy is essential to counteract the water ballast when she is on her side.

How about using the poor ply as patterns, which others could also "borrow", and use the £20 a sheet 4mm and 6mm birch which is readily available and is very strong and bends beautifully according to my son.

Brian

[Chris Waite]

"Any intelligent fool can make things [bigger and] more complex -

It takes a touch of genius and a lot of courage to go in the opposite direction" - Einstein


1.  There are two reasons for avoiding rigid wooden tanks.

a: They need to be openable for inspection and repair, which means a reasonable size waterproof hatch - one of the biggest problems in a dinghy.

b: There is a water air interface so you need an air vent and then you cannot pump out the last few litres - basically most of the bottom half of such a wide flat tank - as even with a strum box the pump will start sucking air before you get there.

2.  OK jolly Admin Major.  Which is more expensive and more complicated, MORE COMPLICATED, two flexi-watertanks (about £160 actually), or an electrical pump, battery and solar panel system, and which is more likely to go wrong when you need it most?  Like the battery being on it's side and underwater in your scenario;  most dinghies, including this one have buoyancy tanks (or bags) for moments when they fill up with oggin and a thing called a bailer to get rid of bilgewater.  Remember that the nice thing about this ballast is it doesn't weigh anything extra when it is surrounded by its own kind.

3.  Thanks for your comments Brian - you have reiterated what I said about draining the system - bows-up on the beach and open the seacock.  If it takes too long (and easier if you have an extra valve on each tank), you can pump out one or both before reaching the shore, or while bows-up, blocking the ramp.

I have to say I was quite surprised to hear of the decision to put the ballast tanks on the 'Raid' anywhere other than as far down in the bilges as they could possibly be.  The buoyancy tanks on this boat will be fore and aft and built either up to, or as close as practical to, the decks covering the ends - the bit about tall hulls having buoyancy high up, again.

Similarly, I did say in my last message that if I decide against the present ply then it will form a useful template for the real thing, though this hull is intentionally so simple that templates will be dead easy even from the finished product.  What I actually want to know is where your son, or anybody, gets hold of this Birch stuff, particularly at twenty quid???

4.  Anders - you're on!

Christo the W

"You have achieved perfection in design, not when there is nothing more you can add, but when there is nothing more you can take away"  - Antoine de Saint Exuprey

[Ratcatcherjohn]

Good afternoon Chris          This may be a bit too agricultural for a craftsman of your sophistication
 
http://www.wickes.co.uk/invt/164521
 
And it needs all the open edges sealing.
 
Regards  John
 

---

Date: Sat, 12 Nov 2011 04:28:54 -0800
From: [hidden email]
To: [hidden email]
Subject: Re: Evolving 'Polly Wee'

"Any intelligent fool can make things [bigger and] more complex -

It takes a touch of genius and a lot of courage to go in the opposite direction" - Einstein


1.  There are two reasons for avoiding rigid wooden tanks.

a: They need to be openable for inspection and repair, which means a reasonable size waterproof hatch - one of the biggest problems in a dinghy.

b: There is a water air interface so you need an air vent and then you cannot pump out the last few litres - basically most of the bottom half of such a wide flat tank - as even with a strum box the pump will start sucking air before you get there.

2.  OK jolly Admin Major.  Which is more expensive and more complicated, MORE COMPLICATED, two flexi-watertanks (about £160 actually), or an electrical pump, battery and solar panel system, and which is more likely to go wrong when you need it most?  Like the battery being on it's side and underwater in your scenario;  most dinghies, including this one have buoyancy tanks (or bags) for moments when they fill up with oggin and a thing called a bailer to get rid of bilgewater.  Remember that the nice thing about this ballast is it doesn't weigh anything extra when it is surrounded by its own kind.

3.  Thanks for your comments Brian - you have reiterated what I said about draining the system - bows-up on the beach and open the seacock.  If it takes too long (and easier if you have an extra valve on each tank), you can pump out one or both before reaching the shore, or while bows-up, blocking the ramp.

I have to say I was quite surprised to hear of the decision to put the ballast tanks on the 'Raid' anywhere other than as far down in the bilges as they could possibly be.  The buoyancy tanks on this boat will be fore and aft and built either up to, or as close as practical to, the decks covering the ends - the bit about tall hulls having buoyancy high up, again.

Similarly, I did say in my last message that if I decide against the present ply then it will form a useful template for the real thing, though this hull is intentionally so simple that templates will be dead easy even from the finished product.  What I actually want to know is where your son, or anybody, gets hold of this Birch stuff, particularly at twenty quid???

4.  Anders - you're on!

Christo the W

"You have achieved perfection in design, not when there is nothing more you can add, but when there is nothing more you can take away"  - Antoine de Saint Exuprey

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[philoxuk]

Hi Chris,

0. Possibly, but in January I'm glad I don't have to get my hand wet to put my rudder down  ;-)

1a. RWO 6" hatch (with O ring). You shouldn't be surprised at what you can do through a 6" hole!?

http://www.ldcsailing.com/rwo-hatch-6.ir?cName=boat-parts-multi-class-hardware-hatches

1b. Indeed so, but with my Wayfarer the pump intake hose nestles alongside the CB case on the _opposite_ side to the (bulkhead mounted) Whale pump, so by strategic weight shifting I can run the dregs round to there & pump out all but a saucer full before settling down for the evening. But the bags idea sounds fine to me anyway.

2. With you all the way on that one!

3a. I reckon if you put your outlet in the right place in the skeg it should self-drain as you race back to the slip on the gentle evening breeze....

3b. I use Totton Timber for this stuff for work, although not much down to 4mm, but what I've had is good stuff with nice even laminations & I don't think I've ever seen a void. From Latvia rather than Brazil. It does support mould growth if it gets wet though (see my canoe leeboards), & sometimes the outer lam grain goes across the sheet. And I guess their free delivery doesn't extend to Sussex, although I'm happy to help if we're going to be in the same place at the same time?! £22+vat

http://www.tottontimber.com/birch-plywood-c-22_94_36.html

5. Shouldn't you be tending toward a sinking windsurfer or kitesurfing then? ;-)



Interesting idea about drilling the matrix of holes. I guess you'll fill them with a filleting blend before sheathing - starts to look like boilermaking  (composite rivetting???) ;-). It's got to help (unless the more highly stressed bits turn to poo as you drill the holes?),  but I can't decide if it's worth the effort or not!  Time for a test panel?

Cheers,

Phil.

[alopenboat]

On 12 Nov 2011 at 5:42, philoxuk [via UK HBBR Forum] wrote:

>
>
> Hi Chris,
>
> 0. Possibly, but in January I'm glad I don't have to get my hand wet
> to put my rudder down  ;-)
>
> 1a. RWO 6" hatch (with O ring). You shouldn't be surprised at what you
> can do through a 6" hole!?
>
> http://www.ldcsailing.com/rwo-hatch-6.ir?cName=boat-parts-multi-class-
> hardware-hatches

For water tanks make sure it will be waterproof when the water is
trying to get out rather than in. I tried 3 different designs (all
with O rings) before I found some that are reliable. The ones I have
now look like those. But even then I wouldn't trust then on a free-
flooding tank if the top of the tank was below water level.

On one occasion, with an earlier hatch, I filled the tank too quickly
and the vent couldn't get the air out fast enough. It blew the top
off the hatch!

>
> 1b. Indeed so, but with my Wayfarer the pump intake hose nestles
> alongside the CB case on the _opposite_ side to the (bulkhead mounted)
> Whale pump, so by strategic weight shifting I can run the dregs round
> to there & pump out all but a saucer full before settling down for the
> evening. But the bags idea sounds fine to me anyway.
>
> 2. With you all the way on that one!
>
> 3a. I reckon if you put your outlet in the right place in the skeg it
> should self-drain as you race back to the slip on the gentle evening
> breeze....
>
> 3b. I use Totton Timber for this stuff for work, although not much
> down to 4mm, but what I've had is good stuff with nice even
> laminations & I don't think I've ever seen a void. From Latvia rather
> than Brazil. It does support mould growth if it gets wet though (see
> my canoe leeboards), & sometimes the outer lam grain goes across the
> sheet. And I guess their free delivery doesn't extend to Sussex,
> although I'm happy to help if we're going to be in the same place at
> the same time?! £22+vat
>
> http://www.tottontimber.com/birch-plywood-c-22_94_36.html
>
> 5. Shouldn't you be tending toward a sinking windsurfer or kitesurfing
> then? ;-)
>
>
>
> Interesting idea about drilling the matrix of holes. I guess you'll
> fill them with a filleting blend before sheathing - starts to look
> like boilermaking  (composite rivetting???) ;-). It's got to help
> (unless the more highly stressed bits turn to poo as you drill the
> holes?),  but I can't decide if it's worth the effort or not!  Time
> for a test panel?

Rather defeats the object of buying cheap ply if you have to spend a
fortune on epoxy instead.

--
Hoping for calm nights

Alastair Law,
Yeovil, England.
<http://www.little.jim.freeuk.com>

[Port-Na-Storm]

Hi,
Watching and listening with interest here although I don't have a lot to input.

Seems like your supplier gets his cheap ply the same place as mine.  I've just saturated everything in epoxy and will hope for the best. I would think that by the time you have sheathed inside and out it won't much matter what's in the middle.

If you need a hand getting stuff from Totton, I have more leisure time than Phil.   Although his van is bigger.

I think it would be a good idea to have some way to pump water in, to ensure tanks are filled, as well as pump out.

Now then, Now then, as the recently departed Sirjim'll once said. As to hatches, a well known and respected manufacturer of boats with water ballast, yes Matt Newland I mean you, has moved to the more robust type of screw-in hatch which you can see here.

<a href="http://">http://www.mailspeedmarine.com/deck-hatches-portlights/henderson/watertight-locker-door673893.bhtml

Much more expensive admittedly but a bit more water tight when the pressure is on. It has a pressure rating on the cover if you can read it.

Like Al, I wouldn't trust the cheaper ones not to blow off, and they always cross thread.

Exciting isn't it!
Graham

[Port-Na-Storm]

Lets try that again.

http://www.mailspeedmarine.com/deck-hatches-portlights/henderson/watertight-locker-door673893.bhtml

G

[alopenboat]

On 12 Nov 2011 at 9:45, Port-Na-Storm [via UK HBBR Forum] wrote:


> http://
> http://www.mailspeedmarine.com/deck-hatches-portlights/henderson/water
> tight-locker-door673893.bhtml
>
> Much more expensive admittedly but a bit more water tight when the
> pressure is on. It has a pressure rating on the cover if you can read
> it.

Unfortunately these are not flush which could be a bit of a nuisance.

--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[BrianP]

Edward buys his birch ply from Edens. They were taken over by Meyer Timber and the New Milton depot closed and moved up to Western Dock, Southampton. http://www.meyertimber.com/locations.asp

Here's the birch plywoods. The 6mm has been superb - it seems it's listed as 6.5mm. they also do a 4mm.

http://www.meyertimber.com/products.asp?HeadSection=Plywood&Section=Birch%20Plywood

Chris, do you have a rig already for Polly Wee? You mentioned that you plan a 75/80 sq ft lug. I kept the rig off raid and the mainsail was 75sq ft. So I have mast, gaff and boom to match. She has two reefs. Mast is a bit long at 15' though. Could be a good rig to use for sailing trials and sizing.

Brian

[Paul H (admin)]

Chris,

Sealed gel batteries are..err....sealed and jolly happy to work upside down and they won't complain when you ask them to keep the anchor light glowing. The major downside is that you won't have the excuse to leave your phone switched off.......

I have batteries and solar panels spare because of other hobby activities so a pump would be cost-effective for me, but the logical approach is a Whale pump first like Phils so that you can pump in/out as Grim suggested and not rely on holes and pipe joints below the waterline.

-Paul

[Chris Waite]

OK General Admin.

When you find yourself clinging to your boat, turny-turtle in Chichester Harbour entrance and are groping to reach the underwater switch to your sealed gel battery, I'll be the frightened man with a bucket in the boat capsized next to yours; first one back in command lends a hand and never mind the loser buying a beer, we'll go to the pub and get, er, 'tanked' - what else!

Pumping in, as well as out, sounds like more hard work than risking a sea-cock is worth the biscuit of, or something.  I don't mind manual labour as a little light exercise, but manning the pumps twice every turn round the bay is masochism.

Oh, and Brian thanks very much for the offer of your 'Raid' rig - let's see how the hull goes for a month or two yet and I'll get back to you.

Anyway, I have been a-filleting over the last few days and now stripped the furze of copper stitches, braces, wedges and bindings back and lo and behold, there is a hull of sorts underneath:

























There are a couple of inter-stitch patches that will need adjustment and generally she's kinda small and tall and very narrow forward with at least a tad of unfortunate chipmunk-cheek effect round the chines there, which is why the photographs are from a different angle; admit it, we all have a good side, don't we?

Anyway, I'm allowing myself twenty-four hours or so to get my mind round her appearance, then I've pretty much decided to go for the grid of holes and double-sheathing approach to beefing her up, rather than starting again with real ply.  This is an experiment I owe the world for my affrontery, so watch out chaps - I could end up with the biggest pepper-pot on the planet.  Wish me luck

I'm going in

CW  

[Ratcatcherjohn]

Chris  Just a couple of points  and for once something which may be mildly constructive.  The transoms on TBA are constructed in the manor you describe, with the holes countersunk both sides. Despite many attempts nobody has broken them yet!
 I did learn the hard way to get the epoxy "rivet heads"  off quickly whilst the material is still a bit soft or you could end up with  a "Studded Door" effect which when sanded back is still a "Studded Door " effect but with fewer ply laminates. 
 
Regards  John
 

 

---

Date: Tue, 15 Nov 2011 10:03:12 -0800
From: [hidden email]
To: [hidden email]
Subject: Re: Evolving 'Polly Wee'

OK General Admin.

When you find yourself clinging to your boat, turny-turtle in Chichester Harbour entrance and are groping to reach the underwater switch to your sealed gel battery, I'll be the frightened man with a bucket in the boat capsized next to yours; first one back in command lends a hand and never mind the loser buying a beer, we'll go to the pub and get, er, 'tanked' - what else!

Pumping in, as well as out, sounds like more hard work than risking a sea-cock is worth the biscuit of, or something.  I don't mind manual labour as a little light exercise, but manning the pumps twice every turn round the bay is masochism.

Oh, and Brian thanks very much for the offer of your 'Raid' rig - let's see how the hull goes for a month or two yet and I'll get back to you.

Anyway, I have been a-filleting over the last few days and now stripped the furze of copper stitches, braces, wedges and bindings back and lo and behold, there is a hull of sorts underneath:

























There are a couple of inter-stitch patches that will need adjustment and generally she's kinda small and tall and very narrow forward with at least a tad of unfortunate chipmunk-cheek effect round the chines there, which is why the photographs are from a different angle; admit it, we all have a good side, don't we?

Anyway, I'm allowing myself twenty-four hours or so to get my mind round her appearance, then I've pretty much decided to go for the grid of holes and double-sheathing approach to beefing her up, rather than starting again with real ply.  This is an experiment I owe the world for my affrontery, so watch out chaps - I could end up with the biggest pepper-pot on the planet.  Wish me luck

I'm going in

CW  

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[Port-Na-Storm]

Looking Good Cee Dubbs!

For the record I hadn't envisaged you pumping all the water in, or out. My plan (?) was to let the tanks flood naturally as far as they wanted to and then to pump a bit more just to make sure they were filled right to the brim. Similarly pump out enough to make her lighter but let gravity do the rest as she is pulled out. I'm sure you could work out the whys and wherefores of all the sea cocks etc, to make it work, but I'm damned if I can.

Toodle pip.
Graham

[alopenboat]

I have developed a healthy dislike for holes through the bottom of my
boat so my tanks are filled and emptied through fittings on the deck.

I used to fill from a hose pipe and pump out by hand. Sometimes there
wasn't a convenient tap and pumping out by hand gets boring after a
while (70 litres in a Paradox).

Now I have an electric pump to fill and an electric pump to empty and
a much more relaxed attitude.

My AGM battery states it is completely sealed, can be mounted at any
attitude and will not be damaged by being submerged in water.



On 15 Nov 2011 at 11:38, Port-Na-Storm [via UK HBBR Forum] wrote:

>
>
> Looking Good Cee Dubbs!
>
> For the record I hadn't envisaged you pumping all the water in, or
> out. My plan (?) was to let the tanks flood naturally as far as they
> wanted to and then to pump a bit more just to make sure they were
> filled right to the brim. Similarly pump out enough to make her
> lighter but let gravity do the rest as she is pulled out. I'm sure you
> could work out the whys and wherefores of all the sea cocks etc, to
> make it work, but I'm damned if I can.
>
> Toodle pip.
> Graham
>
> -----
> Port-Na-Storm
>
> http://port-na-storm.blogspot.com/
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--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[Paul H (admin)]

alopenboat wrote

I have developed a healthy dislike for holes through the bottom of my
boat so my tanks are filled and emptied through fittings on the deck.

I used to fill from a hose pipe and pump out by hand. Sometimes there
wasn't a convenient tap and pumping out by hand gets boring after a
while (70 litres in a Paradox).

Now I have an electric pump to fill and an electric pump to empty and
a much more relaxed attitude.

My AGM battery states it is completely sealed, can be mounted at any
attitude and will not be damaged by being submerged in water.

Cee Dubs,

I told you so!   

[Anders]

Just a few thoughts.

The hull looks good. I like it. Its tall and slim. But thats what you wanted, no.

Second and last: If the plywood is delaminating, I would personally not go on with the construction. Never mind how many layers of whatever you put on, if the core isnt sound, its not going to be a healthy build.
I personally cut up a hull of the same size some years ago because of delaminating.

Think of it this way: Moneywise, what you´ve done so far is just a smal percentage of the total cost and labour wise its the same story.

[Paul H (admin)]

In my experience delaminating tends to be limited to a local area, due to lack of glue.

Often I fixed it by dribbling epoxy into the end grain. If the paper thin veneer has not bonded well its useless - so I strip it off with a thin blade and seal with a coat of epoxy, which greatly improves the strength of the inner core.

-Paul

[Chris Waite]

Now listen here young Admin

What you said was that Grum had suggested pumping both ways, which he denies; it's Al that sits in air conditioned comfort, sipping tea, flicking idly through magazines, pressing buttons and occasionally waggling a yuloh around....    and that's what you can do if you have a lid.

Ratcatcher - thanks for confirming that once epoxy bolted, you can run and outboard off the ensuing transom.

Anders, I take your point.  Actually delaminating is about the only thing it isn't doing.  There is the odd localized patch which is quite apparent and I have in the past done exactly what Paulie suggested - get some epoxy down the area of the fault and clamp it together until set; mostly the problem is that it's a bit fragile and tends to split.  It is very light and if I can properly support it in an epoxy-sheathing envelope, I think it may well "go the distance".
 
Quite which distance I'm not entirely sure yet; I have been out today looking at other sources.


The hull looks strange from some angles, but good from others, I'm having a consider about whether I can get rid of some of the 'strange'.  Tall and slim (should I call it 'Ipanema' instead?) - I think I've been standing too close to it:






























Becomes this from the other end of the courtyard:






























If you look at the line of the chine from the quarter in my last message, it curves round satifactorily as starts to run forward then at its lowest point it appears to head up in a straight line, eventually curving inward in a drastic overhang as it disappears toward the stem.  From inside the hull it looks as if it almost has a reverse shear over the forefoot.  Actually from other angles, it does none of these things

Glory be, I've produced a monster

CW

(Ipanema?  Well maybe Littlehampton - its about three miles away at the mouth of the Arun:

Small and pale and old and ugly
This bloke from Littlehampton goes limping
And when he passes, each one he passes
Goes:"Ugh!")

[Anders]

Some ugly ducklings later turn into pretty swans.

[Port-Na-Storm]

Cee Dubbs,
All of my boats look better the further away you stand.

I'll deny saying this later.

Graham.