Moody 35

boatmike

boatmike

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Well I have finally been and done it. After going from sail to motor (largely wanting to do French Canals) I have taken the plunge and bought an exceptionally nice Moody 35 to get back to sailing at 79. [Inappropriate content deleted] Cant wait to shut down the old iron spinnaker and cruise along in silence once more! One question then aimed at other Moody owners or similar. She has the original Thornycroft 35HP with 2 blade prop. Thinking of replacing with Brunton Autoprop or other feathering prop to get a bit more power and less drag. Anyone done similar?
 
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I found the motoring perfomance of our S31 with Volvo two blade quite pathetic, talked to Darglow and fitted a 3 blade Flexifold folder, no increase in drag when sailing, more than a knot extra speed and lower fuel consumption. Downside was the price, £1800 but worth it.
We had a VP 3 blade folder on a previous boat, it was cheaper with good perfomance too but the tiny anodes struggled to last 1 season.
 
I've got a Gori two-bladed folder on my Moody 31, and am very happy with it. Excellent thrust, both forward and in reverse. Occasionally it has failed to open when engaging reverse, but a touch forward cures that - and it hasn't happened (famous last words) since I dismantled and cleaned it up.
 
Disappointed with my Brunton. Would not recommend it. Also I believe the French canals have a lot of weed. My Brunton does seem susceptible to collecting weed in the same way a fixed one does when sailing. I know that you will be motoring in the canals but you might ask around to see if a fully folding one is better regarding weed . ie when just at the bank side, or sailing with it folded. Having not had one I do not know but I would be inclined to ask first.. The Brunton on my boat uses more fuel & greater prop wash compared to the old fixed blade.
However, with a Moody 35 you may do a lot of motor sailing, in which case the Brunton excels- Horses for courses.
 
Quandary said:
I found the motoring perfomance of our S31 with Volvo two blade quite pathetic, talked to Darglow and fitted a 3 blade Flexifold folder, no increase in drag when sailing, more than a knot extra speed and lower fuel consumption. Downside was the price, £1800 but worth it.
We had a VP 3 blade folder on a previous boat, it was cheaper with good perfomance too but the tiny anodes struggled to last 1 season.
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It sounds as if your Volvo prop was not well matched to the boat. In my slightly larger boat with the Volvo 2-blade I get much the same speed as sister-ships with the 3 but at higher revs. In retrospect, I would have preferred the 3 but took the agent's advice at the time of buying. In spite of this, our cruising speed under power is about 6.5kn at 2,500 rpm.
 
johnalison said:
It sounds as if your Volvo prop was not well matched to the boat. In my slightly larger boat with the Volvo 2-blade I get much the same speed as sister-ships with the 3 but at higher revs. In retrospect, I would have preferred the 3 but took the agent's advice at the time of buying. In spite of this, our cruising speed under power is about 6.5kn at 2,500 rpm.
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That's impressive, I would need a following wind to do that.
 
Daydream believer said:
Disappointed with my Brunton. Would not recommend it. Also I believe the French canals have a lot of weed. My Brunton does seem susceptible to collecting weed in the same way a fixed one does when sailing. I know that you will be motoring in the canals but you might ask around to see if a fully folding one is better regarding weed . ie when just at the bank side, or sailing with it folded. Having not had one I do not know but I would be inclined to ask first.. The Brunton on my boat uses more fuel & greater prop wash compared to the old fixed blade.
However, with a Moody 35 you may do a lot of motor sailing, in which case the Brunton excels- Horses for courses.
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Obviously never sailed a Moody 35. Excellent sailing boats. Not so good in light airs but then neither are the majority of cruising boats.

Ink
 
Congratulations. Nice boat. A feathering propeller such as a Featherstream would indeed be a great addition, although you may well find the existing prop perfectly adequate. I have a 2 blade on my Bavaria which has less hp (30 vs 35) and only a bit less displacement (5.5 vs6 tonnes) and performs well. While a 3 blade is potentially better, the 2 blade is normally larger diameter and would guess that they have fitted one with a reasonable blade area rather than the skinny ones you sometimes see. Give it a go before spending the £2k+ for a replacement.
 
We had the Thornycroft 35hp in our 376 but with the standard fixed 2 blade prop limiting revs, it only produced around 27hp. Changed to 43hp engine with 3 blade Featherstream, pitched to allow us to reach max bhp. Far better bite motoring into wind and chop and eliminated prop walk in astern and less drag when sailing .
 
No, I am not forgetting that, but the difference in drag is far less than with a 3 blade fixed and just suggest that in terms of motoring performance it is perhaps better to go with what is fitted before making expensive changes. In fact one might be tempted to consider as I did fitting a 2 blade FlexoFold folder at roughly half the price!
 
Quandary said:
I found the motoring perfomance of our S31 with Volvo two blade quite pathetic, talked to Darglow and fitted a 3 blade Flexifold folder, no increase in drag when sailing, more than a knot extra speed and lower fuel consumption. Downside was the price, £1800 but worth it.
We had a VP 3 blade folder on a previous boat, it was cheaper with good perfomance too but the tiny anodes struggled to last 1 season.
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+1 on these comments on the Volvo folder. Very effective ahead and astern but pathetic anodes. A real plus is the ease of stripping down and servicing. I understand that some of the feathering ones ?brunton? Require periodic refurbs at the manufacturer and at some cost.
 
I would tend to agree with Tranona here.

Firstly, any (fixed) prop on a sailboat is a compromise and mostly due to lack of blade area. In fact most props on sailing boats are really too small and with too high a blade loading, because surface area means drag.

A 2- bladed prop, left to freewheel, has the same resistance as a 3-bladed feathering prop.

At a relative speed of 0.9 you will lose 4% in speed with either a 2-blade freewheeling or a 3- blade feathering. 8% with a 3-blade freewheeling.

At hull speed you loose 2% with either. 4% with a 3-blade freewheeling.

Until I had thoroughly tried out the boat with the current set-up, I certainly wouldn't be investing a good portion of my kid's college fund to change that. And even then, unless you absolutely must have a 3-bladed prop to get that power into the water or couldn't let your prop freewheel, I would choose a folder over a feathering one for low drag.
 
Well that got mister Fred Drift awake didn't it? Firstly I have already done the French canals in my Aquastar and have no intent on trying it in a Moody 35 Daydream believer. I think you misread my original post. Secondly many thanks to those who actually answered my original post. I think that replacing the 2 blade prop with a 3 blade would obviously give more efficient thrust but also more drag when sailing so a feathering 3 blade should give more thrust than a fixed 2 blade and reduce sailing drag. Win Win.
However having previously fitted a Brunton on my catamaran I found it excellent but the stupid little anode on the front never lasted long as Quandry suggested. So is the Darglow thingy better than the Brunton or vice versa?
 
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