Advice please re prop and clearance

[bigcol]

Hi All

 

Any help or advice please.

 

As some of you know I have a Dutch steel crusier here on the GU

Last month as posted had 2 short trips out giving our new beta 50 hp a run from Willowbridge to Peartree bridge

On the way there got a sleeping bag stopping the prop I had to go in!

On the way bag got a jacket & rope also stoping the prop and having to go in for the second time!

as I haven't got a weed hatch fitted

Never again do I want to go in if I can help it and with great advice from the forum,Last week I was craned out to have a weed hatch put in,and inspect prop

 

When the boat was craned out, the gap between the prop and the bottom of boat was just 1 cm,also from the Skeg 2 cm

The prop is the original at 18x 10', as the boat is 1940 I imagine there was a big lump in thereorignally

on top of this the engine max hp is 2800 but only manages 2200,? and have been told the prop is well too big

I've been offered a 16x12 which will give me a lot more clearance between skeg and bottom of boat,and have been told it would be better?

 

Will this prop be better for me?

Also the biggest weed hatch I can have is 18 x 10 will this be a problem?

 

Many thanks in advance

 

Col

Edited August 14, 2011 by bigcol

[bigcol]

I just realised havent mentioned boat sizes

 

50 ft

7th beam water line

14 ton as weighed on crane Friday, with me not on the boat. Lol

Draft 28 inches

 

I imagine some folks may be bored in answering similar questions

 

But have looked on the forum and use I know it's easy,but I'm so confused

 

The 16x12 ive been offered for exchange for my old 18x.10' fits nicely on the shaft, giving me lots of clearance, but can I be so lucky?

 

Col

[The Pipe]

Your missing something which is BAR "blade area ratio" basically how big are the bats in width. If the blades look about the same profile in width try it. Propping a boat is allot of try and see if it works. It is possible to remove a propeller with the boat in the water if you have a weed hatch without swimming. The weed hatch is big enougth at sizes quoted.

[zenataomm]

It took them three attempts to prop the QE2 correctly.

 

As for gap between the tips of the ears and the uxter plate or the skeg, Peter Thompson once said 3" is the most common width of wood to be found floating in the cut ........ mind you we've gone decimal since then so best convert it into Kilos.

[Mike Jordan]

Ive always allowed a tip clearance of 2" on the understanding that this will ensure that noise is not generated.

Lopping 2" off the diameter and adding it to the pitch is normally considered a rule of thumb way of getting the same result in terms of power absorbed/delivered. When the weed hatch is installed, can you do a prop change while afloat? if so, the 16 X 12 might be worth a try, it improves the tip clearance a little. But may not solve all your problems. The weed hatch size is similar to most in narrow boats and its got to beat getting in!!

Mike.

[bizzard]

If you wish to change a prop thats too big to come through the weed box whilst the boats in the water,tie two ropes around the topmost blade,take one end up outside the counter and so onboard,and the other end up through the weedbox.once released from the shaft the prop can then be juggled up over the stern,reverse order to refit. bizzard

[Tam & Di]

I have a Dutch steel crusier here on the GU

Last month as posted had 2 short trips out giving our new beta 50 hp a run from Willowbridge to Peartree bridge

On the way there got a sleeping bag stopping the prop I had to go in!

On the way bag got a jacket & rope also stoping the prop and having to go in for the second time!

as I haven't got a weed hatch fitted

Col

 

What happened to the art of getting rubbish off the blades using a long shaft? Working narrowboats do not have weed hatches, but I've never been in the water to clear the blades. My view of water is that it is all very well for floating boats in and washing in it, but going into it or drinking it is a step too far. I admit we did have to put the motor on the cill a couple of times to cut barbed wire off, but I would not have wanted to do that either in the water or via one of these weed hatch thingeys.

Edited August 14, 2011 by Tam & Di

[bizzard]

What happened to the art of getting rubbish off the blades using a long shaft? Working narrowboats do not have weed hatches, but I've never been in the water to clear the blades. My view of water is that it is all very well for floating boats in and washing in it, but going into it or drinking it is a step too far. I admit we did have to put the motor on the cill a couple of times to cut barbed wire off, but I would not have wanted to do that either in the water or via one of these weed hatch thingeys.

Sounds like you could do with one,though a tall one,if your running loaded boats. bizzard

[Tam & Di]

Sounds like you could do with one,though a tall one,if your running loaded boats. bizzard

 

I think my point was that I never found it a problem getting rubbish off the blades with a long shaft other than a couple of times where we picked up a great entanglement of barbed wire and on another occasion a sprung bed base. I would not have wished to tackle those without being able to see exactly what I was doing - certainly not either in the water or through a narrow box. You'd probably need arms at least three feet long anyway

 

Why are they known as weed hatches, by the way? Surely they should be shopping trolley hatches or old rope hatches.

Edited August 14, 2011 by Tam & Di

[The Pipe]

What happened to the art of getting rubbish off the blades using a long shaft? Working narrowboats do not have weed hatches, but I've never been in the water to clear the blades. My view of water is that it is all very well for floating boats in and washing in it, but going into it or drinking it is a step too far. I admit we did have to put the motor on the cill a couple of times to cut barbed wire off, but I would not have wanted to do that either in the water or via one of these weed hatch thingeys.

Weed hatches are good but not for a boat that is going to be loaded then it would have to come up to the counter deck and then you cannot reach the blade without a hook anyway.

Razor wire is more fun to deal with than barbed a right pig to clear without bleading yourself dry. Had fun with a spring mattress and no weed hatch did not help breaking the boat hook either.

[bizzard]

I think my point was that I never found it a problem getting rubbish off the blades with a long shaft other than a couple of times where we picked up a great entanglement of barbed wire and on another occasion a sprung bed base. I would not have wished to tackle those without being able to see exactly what I was doing - certainly not either in the water or through a narrow box. You'd probably need arms at least three feet long anyway

 

Why are they known as weed hatches, by the way? Surely they should be shopping trolley hatches or old rope hatches.

Unless the waters murky you can see the prop quite clearly through the weed hatch,whereas i doubt whether you could from the bank and so have to poke about by feel with the shaft.

I presume your shaft has a sharpened inner edge of the pike hook,well this can be poked down a weed box to free weed or cut rope as can long handled wire croppers to cut through barbed wire ect, and all manner of other long handled tools too. I appreciate that your working your boat traditionally,but i'm sure a weed box would make life much easier for you. The name weed hatch is self explanitary surely,or call them what you wish. And of course can almost always be made as wide as you want. regards bizzard

[Tam & Di]

Unless the waters murky you can see the prop quite clearly through the weed hatch,whereas i doubt whether you could from the bank and so have to poke about by feel with the shaft.

I presume your shaft has a sharpened inner edge of the pike hook,well this can be poked down a weed box to free weed or cut rope as can long handled wire croppers to cut through barbed wire ect, and all manner of other long handled tools too. I appreciate that your working your boat traditionally,but i'm sure a weed box would make life much easier for you. The name weed hatch is self explanitary surely,or call them what you wish. And of course can almost always be made as wide as you want. regards bizzard

 

 

Sorry, no. We just live in totally different worlds. A boatman's long shaft is a standard boatpole about 16' long - no sharp inner edge. The bit you miss is that we (and I think I speak for generations of working boatmen on the canals) had no great difficulty removing the majority of rubbish from the blades. "Weed" hatches were a much later invention, specific to pleasure boats owned by people who probably don't even have a long shaft. I think they were probably first introduced on hireboats, and the hire company would certainly not want to refer to them as a "barbed wire" hatch.

 

Another possibility, especially if it is rope around the blades, is to hook the shaft into it, put the engine in the appropriate gear and decompress it, and have someone turn it over with the starting handle. Do you know what a starting handle is? Sorry, being a bit snotty. As I said, your canal is nothing like mine. A weed hatch would NOT have made our lives easier.

Edited August 14, 2011 by Tam & Di

[mykaskin]

A boatman's long shaft is a standard boatpole about 16' long - no sharp inner edge.

 

Isn't it a little long for clearing the prop? I use my cabin shaft (about 8 foot long) usually without bother.

 

Mike

Edited August 14, 2011 by mykaskin

[bizzard]

Sorry, no. We just live in totally different worlds. A boatman's long shaft is a standard boatpole about 16' long - no sharp inner edge. The bit you miss is that we (and I think I speak for generations of working boatmen on the canals) had no great difficulty removing the majority of rubbish from the blades. "Weed" hatches were a much later invention, specific to pleasure boats owned by people who probably don't even have a long shaft. I think they were probably first introduced on hireboats, and the hire company would certainly not want to refer to them as a "barbed wire" hatch.

 

Another possibility, especially if it is rope around the blades, is to hook the shaft into it, put the engine in the appropriate gear and decompress it, and have someone turn it over with the starting handle. Do you know what a starting handle is? Sorry, being a bit snotty. As I said, your canal is nothing like mine. A weed hatch would NOT have made our lives easier.

If you say so.But if i ever spot you using a sharpened pike on a stick 'beware'. Also i'm a retired mechanic, but still do a few marine repairs,so do happen to know a bit about starting handles and such like.Also been boating for about 50 years in my spare time,and teaching sailing ect.This has become too tedious,i'm bored.

Lets call it quits bizzard

[Timleech]

Isn't it a little long for clearing the prop? I use my cabin shaft (about 8 foot long) usually without bother.

 

Mike

 

Absolutely.

 

I've spent some time in the cut, in the past, when desperate measures were needed and, in the words of the Blessed Margaret, there was no alternative.

One memorable occasion in the shadow of the M6, sharing one wetsuit with the captain of Jupiter & Saturn, doing alternate stints for as long as we could stand it cutting a coil of toughened wire off the blades. There was a film of ice on the cut at the time!

 

Tim

[Tam & Di]

Isn't it a little long for clearing the prop? I use my cabin shaft (about 8 foot long) usually without bother.

 

Possibly - it depends on how close to the bank you can get. In fact of course if it is deep enough to come alongside you actually have to keep the boat away a bit so you can get a shaft to the blades. Especially the case if you've got a load on or if the bank is a bit high, otherwise your shaft is at too steep an angle.

 

The nearest I've ever come to having to be in the water was to put a plank from the bank onto the top of the rudder and reach under from there.

 

Anyway, despite blizzard's assertions I've never felt need for a weed hatch on any of the craft we have worked through the ages.

[MtB]

I've always considered the term 'weed hatch' a bit of a misnomer. It's a stupid place to keep your weed, the water really messes it up and you generally just end up buying more.

 

As others have implied, weed hatches come into their own for cutting your stern line off the prop when you've inadvertently allowed it to fall in the water. Can you guess how I know this?

 

Mike

 

Probably best if I get my coat now...

[XAlan W]

What happened to the art of getting rubbish off the blades using a long shaft? Working narrowboats do not have weed hatches, but I've never been in the water to clear the blades. My view of water is that it is all very well for floating boats in and washing in it, but going into it or drinking it is a step too far. I admit we did have to put the motor on the cill a couple of times to cut barbed wire off, but I would not have wanted to do that either in the water or via one of these weed hatch thingeys.

 

I was also wondering about that, only rubbish that was not able to be removed either by long shaft, or modified railway shunters pole, was wire. bed springs etc. & that was a cill job so as to be able to see what you we doing.

[bigcol]

Hi again

 

2 questions

 

Where can we buy these special tools re clearing prop that screw in and cut?

And does the change from a 18 x 10 to a 16x 12 seem at all feasible with my situation

The hole s been cut for the weed hatch, the weed hatch is being fabricated as we speak

 

 

Many thanks in advance

 

Col

[nb Innisfree]

Hi again

 

2 questions

 

Where can we buy these special tools re clearing prop that screw in and cut?

And does the change from a 18 x 10 to a 16x 12 seem at all feasible with my situation

The hole s been cut for the weed hatch, the weed hatch is being fabricated as we speak

 

 

Many thanks in advance

 

Col

 

If prop diameter is reduced then the correct thing to do is increase blade area, any blade area lost needs to be replaced somewhere and either wider blades or a 4 blade prop is the way to go. If you want a 16 incher then I suggest going to Crowthers and ask them to calculate one for you (I do believe though that now they won't give full details unless you order a prop from them)

 

You might have to have one manufactured to get the correct size but IMO it's worth the expense to get it right first time.

[ditchcrawler]

Possibly - it depends on how close to the bank you can get. In fact of course if it is deep enough to come alongside you actually have to keep the boat away a bit so you can get a shaft to the blades. Especially the case if you've got a load on or if the bank is a bit high, otherwise your shaft is at too steep an angle.

 

The nearest I've ever come to having to be in the water was to put a plank from the bank onto the top of the rudder and reach under from there.

 

Anyway, despite blizzard's assertions I've never felt need for a weed hatch on any of the craft we have worked through the ages.

Well I was expecting Mrs Sara Chertsey to come in about her stick with a pigs tail on it

[bargemast]

What happened to the art of getting rubbish off the blades using a long shaft? Working narrowboats do not have weed hatches, but I've never been in the water to clear the blades. My view of water is that it is all very well for floating boats in and washing in it, but going into it or drinking it is a step too far. I admit we did have to put the motor on the cill a couple of times to cut barbed wire off, but I would not have wanted to do that either in the water or via one of these weed hatch thingeys.

 

 

Those weed-hatches are something typical of the U.K.narrow (pleasure) boats, as far as I know. I spend most of my working life running commercial barges in Continental waters, none of them had a weed-hatch. I've always apart from once, managed to clear the blades with different lenghts of shaft, and mostly while working from the dinghy. The one time I didn't manage was when I picked-up a truck tire around the prop on a laden pusherbarge, that stopped the engine just at a lock entrance, and that took divers with underwater cutting gear 4 hours to clear, a weed-hatch wood have been useless anyway, drawing more than 2 metres.

 

If they would be a useful feature all boats and barges would have one, they are another risk to sinking a boat, if they are not leakproof as you can read in occasional posts on here. To me, the lesser holes there are under water the better it is.

 

Peter.

Edited August 18, 2011 by bargemast