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prop size?

savageseadog

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At a guess, something like 18 X 13 but you would be best advised to contact a propeller supplier
 

emandvee44

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From: Plymouth, living SE coast Spain, boat:Spain
I have a Warrior 38 with a Brunton auto prop, the prop has failed and with Bexit complications (I am in Portugal) a repair is not on. Can anyone advise me as to what size prop I should buy. The engine is a Volvo D2 40 with a 130S saildrive.
Paul, contact Bruntons. They are very helpful and will be able to tell you what size is required for your engine/boat.
M.
 

PCUK

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Boat WLW, Displacement, gearbox ratio, engine bhp and max revs? From this you will be able to look at a prop' calc' program and find what you need. Why can't you post the prop' to Bruntons?
 

Tranona

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Probably a 17*11 3 blade would be most appropriate. That is what is fitted on other boats with the same engine and similar displacement. However suggest you contact Sillette who are the agents for Radice props and they will do the calculations for you.

Sillette Sonic Ltd
 

penfold

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Refurbishment of the autoprop won't be much more than a new fixed blade prop, assuming it's not been eaten by mechanical sharks.
 

Daydream believer

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When you say the prop has "failed" how exactly has it failed?You can put new bearings in the blades yourself I am sure.
I have not taken mine apart, but it cannot be rocket science :unsure:
If you do not want to replace the Brunton why not ask them if they would do an exchange for another type. That way they will determine the pitch from the one you send back & they "may" give you a substantial discount. Gotta be worth a punt. You will not be going anywhere for a while i suspect. Is there not a marina engineer in Portugal who can take it off for you & send it back to UK on your behalf.
 

penfold

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When you say the prop has "failed" how exactly has it failed?You can put new bearings in the blades yourself I am sure.
I have not taken mine apart, but it cannot be rocket science :unsure:
If you do not want to replace the Brunton why not ask them if they would do an exchange for another type. That way they will determine the pitch from the one you send back & they "may" give you a substantial discount. Gotta be worth a punt. You will not be going anywhere for a while i suspect. Is there not a marina engineer in Portugal who can take it off for you & send it back to UK on your behalf.
Autoprops are self-pitching so do not provide any guidance for selecting a fixed pitch prop.
 

Daydream believer

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Penfold said
Autoprops are self-pitching so do not provide any guidance for selecting a fixed pitch prop.

The pitch is not marked on the prop, but Brunton might know what pitch it has been set to because the blades are marked with a reference No which may be unique to the prop. Have you asked them if they can determine it from the number
 
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penfold

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Autoprops have no pitch setting, they self-pitch according to boat speed and throttle setting.

 

Daydream believer

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Autoprops have no pitch setting, they self-pitch according to boat speed and throttle setting.
Going to have to correct you,--they do. In simple terms -The idea is that once your boat is at the correct speed the pitch is at the optimum max pitch.
That pitch is set for your boat; then they vary between that & zero. If under pitched the prop has limited drive.( as initially happened to me on my prop) If over pitched, the engine gets overloaded.( as mine now tends to do). The pitching can be fine tuned by the small splay on the back edge of the blade. (which I believe is how it was adjusted for my boat to give more drive) But it is still set to a specific initial pitch.

If you want to tell me I am wrong, you had better take it up with the MD of Brunton, I have known him for 50 + years, He started there as an apprentice, I am sure that he knows how it works by now.
 
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Tranona

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The maximum pitch may not be set at the same pitch as a correctly sized fixed prop of a different shape and possibly diameter. Using either as a base for the other is misleading. Much better to start from basics with the data for the boat and use a calculator such as Propcalc or Vicprop, which is what I did for post #6. The size suggested is the same as used on a Bavaria 40 of similar displacement and the same engine/drive. Sizes for fixed and feathering/folding props are often different from fixed. My boat came with a 16*13 2 blade fixed and my folder is 16*11. Both are spot on in trials.

Always best to get the supplier to do the calculations as they will overlay the result of the calculator (most use similar programmes) with their experience of the particular prop they are supplying.
 

Daydream believer

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The maximum pitch may not be set at the same pitch as a correctly sized fixed prop of a different shape and possibly diameter. Using either as a base for the other is misleading. Much better to start from basics with the data for the boat and use a calculator such as Propcalc or Vicprop, which is what I did for post #6. The size suggested is the same as used on a Bavaria 40 of similar displacement and the same engine/drive. Sizes for fixed and feathering/folding props are often different from fixed. My boat came with a 16*13 2 blade fixed and my folder is 16*11. Both are spot on in trials.

Always best to get the supplier to do the calculations as they will overlay the result of the calculator (most use similar programmes) with their experience of the particular prop they are supplying.
It is reasonable to suggest different pitches for different props.
In fairness I did suggest sending the prop back to Brunton first. I am sure that they would know how to make the jump from one to the other. They also know how to design props world wide, having supplied notables such as Belgian warships in the recent past. Although
I am not aware of any modern warships working with sail, perhaps they have not caught up yet, or are deliberately trying to avoid being seen. Works for me ;)
 

Tranona

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Why involve Bruntons if he is going to buy a fixed blade prop? I have given a link to the agent for Radice who make the Volvo saildrive props. They will supply the correct size based on the data for the boat - and I am pretty sure the size I suggested won't be far out. There is nothing magic about calculating the size for a fixed blade prop.
 

Daydream believer

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Why involve Bruntons if he is going to buy a fixed blade prop? I have given a link to the agent for Radice who make the Volvo saildrive props. They will supply the correct size based on the data for the boat - and I am pretty sure the size I suggested won't be far out. There is nothing magic about calculating the size for a fixed blade prop.
Seems odd going from an adjustable to a fixed . No accounting for taste. But I had missed that point. - careless
 

shaunksb

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I broke my Brunton’s prop.

I sent it back to them they refurbished and returned it for under £200 IIRC.

_______________________
 
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