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TOPIC: Mast testing

Mast testing 31 Aug 2016 08:40 #79610

  • Charles Mclaren
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Take a small hammer and on a quiet day tap yr way along the mast... If there is internal rot the noise returns will change. With a small fine drill u can check the extent. If the mast survives the raising for inland sailing wdn't be too worried. C

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> On 30 Aug 2016, at 11:59, DBA Forum (SB) - Peter Smith wrote:
>
>
> Hi Nick
> The hoist action has the mast in compression and the sheet in applies a bending action.
> A think a sail on a quiet day with regular visits to the mast support to listen for cracks and groans is the go.
> And it looks to the observer as if you are letting go of the helm and taking a casual stroll along the deck.
>
> Regards Peter
>
>> On 30/08/2016, at 6:47 PM, "DBA Forum (SB) - Nick Baker" wrote:
>>
>>
>> Dear Peter
>>
>>
>>
>>
>> Thank you for your very interesting reply. Sorry I have not acknowledged it sooner, but the email went into my spam bin, and I hadn't checked the forum page. I was quite heartened by your comments; the mast is now up and it occurred to me that the most stressfull moment might be just as it lifts out of the mast support, when the angle of the forestay from the A-frame is at its smallest. And it survived that.
>>
>>
>>
>>
>>
>> I shall keep my fingers crossed again when I hoist the main and sheet in!
>>
>>
>>
>>
>>
>> Best wishes
>>
>>
>>
>>
>>
>> Nick
>>
>>
>>
>>
>>
>> Vrouwe Alberdina 2
>>
>>
>>
>>
>>
>>
>>
Original Message
>>
>> Forum (SB) - Peter Smith
>>
>> Barges subscribers
>>
>> Sent: Wed, 3 Aug 2016 9:43
>>
>> testing
>>
>>
>>
>>
>>
>> Nice looking tjalk. I have no experience with testing the performance of the timber vs a standard. The child bride has a 13 meter sailing boat of 1938 I have been given to restore. The mast is 55 feet long 7 inch dia at the base and 4 inch at the peak. It had rot through 75% of the thichness at the first cross tree. When removed and put on tress els I bent like a boomerang. We cut out the rot and scarfed in a tapered 11 feet length of new select timber. Good scarfs taper at a rate of around 10 to 1.We treated the mast to a good saturation with epoxy (2 pack) wood preserver plus a sleeve of GRP over the scarf. Cracks were filled with flexible sealant and the mast painted. I am lucky it has always painted and thus I comply with it's historic classification.
>>
>> Your mast looks much stouter than mine. I think you hae a lot of meat to play with.To test I would put on tressels and see if it springs, is yes that's good , if soggy then there is a real problem. Prod around the cracks and fittings for rot and if shallow then wood preserve and seal. The preservative creates epoxy reinforced with celulose. Vintage sailboats can have masts with quite a few scarfs at various places where damage was repaired.
>
>

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Mast testing 30 Aug 2016 11:59 #79562

Hi Nick
The hoist action has the mast in compression and the sheet in applies a bending action.
A think a sail on a quiet day with regular visits to the mast support to listen for cracks and groans is the go.
And it looks to the observer as if you are letting go of the helm and taking a casual stroll along the deck.

Regards Peter

On 30/08/2016, at 6:47 PM, "DBA Forum (SB) - Nick Baker" wrote:

>
> Dear Peter
>
>
>
>
> Thank you for your very interesting reply. Sorry I have not acknowledged it sooner, but the email went into my spam bin, and I hadn't checked the forum page. I was quite heartened by your comments; the mast is now up and it occurred to me that the most stressfull moment might be just as it lifts out of the mast support, when the angle of the forestay from the A-frame is at its smallest. And it survived that.
>
>
>
>
>
> I shall keep my fingers crossed again when I hoist the main and sheet in!
>
>
>
>
>
> Best wishes
>
>
>
>
>
> Nick
>
>
>
>
>
> Vrouwe Alberdina 2
>
>
>
>
>
>
>
Original Message
>
> Forum (SB) - Peter Smith
>
> Barges subscribers
>
> Sent: Wed, 3 Aug 2016 9:43
>
> testing
>
>
>
>
>
> Nice looking tjalk. I have no experience with testing the performance of the timber vs a standard. The child bride has a 13 meter sailing boat of 1938 I have been given to restore. The mast is 55 feet long 7 inch dia at the base and 4 inch at the peak. It had rot through 75% of the thichness at the first cross tree. When removed and put on tress els I bent like a boomerang. We cut out the rot and scarfed in a tapered 11 feet length of new select timber. Good scarfs taper at a rate of around 10 to 1.We treated the mast to a good saturation with epoxy (2 pack) wood preserver plus a sleeve of GRP over the scarf. Cracks were filled with flexible sealant and the mast painted. I am lucky it has always painted and thus I comply with it's historic classification.
>
> Your mast looks much stouter than mine. I think you hae a lot of meat to play with.To test I would put on tressels and see if it springs, is yes that's good , if soggy then there is a real problem. Prod around the cracks and fittings for rot and if shallow then wood preserve and seal. The preservative creates epoxy reinforced with celulose. Vintage sailboats can have masts with quite a few scarfs at various places where damage was repaired.
>
>
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Mast testing 30 Aug 2016 10:47 #79559

  • Nick Baker
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Dear Peter




Thank you for your very interesting reply. Sorry I have not acknowledged it sooner, but the email went into my spam bin, and I hadn't checked the forum page. I was quite heartened by your comments; the mast is now up and it occurred to me that the most stressfull moment might be just as it lifts out of the mast support, when the angle of the forestay from the A-frame is at its smallest. And it survived that.





I shall keep my fingers crossed again when I hoist the main and sheet in!





Best wishes





Nick





Vrouwe Alberdina 2






Original Message

From: DBA Forum (SB) - Peter Smith <This email address is being protected from spambots. You need JavaScript enabled to view it.>

To: Sailing Barges subscribers <This email address is being protected from spambots. You need JavaScript enabled to view it.>

Sent: Wed, 3 Aug 2016 9:43

Subject: Mast testing





Nice looking tjalk. I have no experience with testing the performance of the timber vs a standard. The child bride has a 13 meter sailing boat of 1938 I have been given to restore. The mast is 55 feet long 7 inch dia at the base and 4 inch at the peak. It had rot through 75% of the thichness at the first cross tree. When removed and put on tress els I bent like a boomerang. We cut out the rot and scarfed in a tapered 11 feet length of new select timber. Good scarfs taper at a rate of around 10 to 1.We treated the mast to a good saturation with epoxy (2 pack) wood preserver plus a sleeve of GRP over the scarf. Cracks were filled with flexible sealant and the mast painted. I am lucky it has always painted and thus I comply with it's historic classification.

Your mast looks much stouter than mine. I think you hae a lot of meat to play with.To test I would put on tressels and see if it springs, is yes that's good , if soggy then there is a real problem. Prod around the cracks and fittings for rot and if shallow then wood preserve and seal. The preservative creates epoxy reinforced with celulose. Vintage sailboats can have masts with quite a few scarfs at various places where damage was repaired.

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Mast testing 03 Aug 2016 10:43 #78493

Nice looking tjalk. I have no experience with testing the performance of the timber vs a standard. The child bride has a 13 meter sailing boat of 1938 I have been given to restore. The mast is 55 feet long 7 inch dia at the base and 4 inch at the peak. It had rot through 75% of the thichness at the first cross tree. When removed and put on tress els I bent like a boomerang. We cut out the rot and scarfed in a tapered 11 feet length of new select timber. Good scarfs taper at a rate of around 10 to 1.We treated the mast to a good saturation with epoxy (2 pack) wood preserver plus a sleeve of GRP over the scarf. Cracks were filled with flexible sealant and the mast painted. I am lucky it has always painted and thus I comply with it's historic classification.
Your mast looks much stouter than mine. I think you hae a lot of meat to play with.To test I would put on tressels and see if it springs, is yes that's good , if soggy then there is a real problem. Prod around the cracks and fittings for rot and if shallow then wood preserve and seal. The preservative creates epoxy reinforced with celulose. Vintage sailboats can have masts with quite a few scarfs at various places where damage was repaired.
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Mast testing 02 Aug 2016 11:49 #78418

  • Nick Baker
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The mast on our 14.3m skutje looks good on the outside, but when investigating longitudinal cracks I have found some evidence of rot. This is probably because the mast has spent a lot of time horizontal and exposed to weather. Obviously it gave me some concern for its strength.

I wondered if anyone has any experience of testing a mast in a horizontal position on two supports, by measuring the deflection when loaded? The deflection could then be compared with a calculated value (quite a simple formula), to compare the modulus of elasticity (E) with standard values for the species of timber. Critical areas of rot would result in an apparent lowering of E. I know that this is the principle of stress grading of timber used in the building industry

Any comments or suggestions would be welcome..

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