Hunter 38 Improvements

Jul 27, 2011
4,989
Bavaria 38E Alamitos Bay
Ha! We are not discussing planing hulls;). Do you have a calculation?:doh: So simple?
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
that is correct, we are not discussing planing hulls. buy the book, read the science, learn about these toys we all enjoy. all your misunderstandings will be explained by one of the greatest sailors ever.

that book will teach you how to sail your boat. that's right, that book will teach you how to sail your bavaria 38E, properly.

the science you request is in that book.

jon
 
Jul 27, 2011
4,989
Bavaria 38E Alamitos Bay
So, I take it you have no objective estimate of the average difference in speed through the water, the same water, between two displacement hull yachts of the same model, one with a folding prop, the other with a 3-blade fixed one. That you cannot detail in what way or ways my statement in post #14 is so terribly misleading. Do you even know what PHRF adjustments are and how they are used? Maybe you need to do some reading.:huh:
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
i have over 1,000,000 miles at sea. i have been sailing 61 years. i am a trained professional. i am a trained instructor. while not much interest in racing , when i have raced in top events, i have won. i retired in 88' and have been sailing sailboats as my first love ever since.
read bethwaite. read bethwaite.

flying spinnakers is easy. try it some time. get a couple of thousand miles with the spinnaker flying and you will understand why i can say this. it's called experience.
well i have sailed aeolus, not motored aeolus well over 100,000 miles. that's experience. i have an Ascow, know what that is? cal20, trinka 12. and a bunch of motorboats too.
it's called experience. i can dock my 42' sailboat, i can dock a 1,000 ft ship. experience.

but don't take it from me, i'm nobody you would trust.

read bethwaite, all the science is in that book. don't be lazy. buy the book. learn to sail properly, share it with friends.

jon:cool:
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
one size does not fit all. if you have watched terry's fabulous videos of his adventures in the PNW you will understand that a fixed 3 bladed prop is a great fit for his location and how he uses his vessel. summer winds are mild, the bays and cuts have strong currents every day. the winds are spun by the high shores and he enjoys exploring everywhere. he lets his prop freewheel when sailing, which highly reduces drag. he loves to sail at every wind speed. it's a great fit for how he uses his boat.

on the great lakes, no tides, no tidal currents. lots of open water with long fetches. using my vessel as a sailboat, not a motorsailer, maximizing sailing speed improves getting from A to B and i find that my boat rides better in a seaway if i push back hard against the waves. aeolus tends to wallow if i don't push back hard against mother nature. i love to sail in strong winds. i just love the ride. like the black runs on the ski hill. i sail with a crew. just not into shorthanded sailing.

so? use the gear that that fits your needs in your location. no two are the same.
 
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Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Looking at KG's math using the PHRF time adjustment the 90 seconds translated into units of speed does not show much mathematical advantage to supporting a purchase of a folding prop.

Listening to sailors that have a folding prop they see their race time gain as more significant than the 90 second calculation from PHRF. Perhaps that is why the PHRF handicap is always challenged by sailors when racing.

The folding prop will improve your sailing speed. The accepted number is 0.5 to 1 knot. It will reduce your efficiency under power about 0.5 to 1 knot. There is a benefit claimed by boaters who hate the prop wash effect that the folding prop reduces the prop walk of their boat making it easier to back up in a straight line.

It is your boat and your choice. They can be a lot of money. How you choose to manage you power needs (getting new sails, adding a 3 bladed prop, getting a new engine... etc) is dependent on the way you approach sailing. I get excited for a fellow boater who tells me he just got new sails. He is in for a lot of fun. I am happy for a boater who is telling me the benefits of his new prop. It seems props always solve the problem the boater was most worried about.

Before you rush out to spend money on a folding prop, perhaps it would be wise to protect your boat budget and take this year to learn about your boat. You may find that the prop is the least of your concerns.
 
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Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
..........Before you rush out to spend money on a folding prop, perhaps it would be wise to protect your boat budget and take this year to learn about your boat. You may find that the prop is the least of your concerns.
Good words of wisdom for any new boat owner!! That is what I was suggesting to in post #5. Given the OP's boat year (2006) it is probably due new sails. In that case think cruising laminate sails if the OP wants more speed while sailing.
 
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Jul 27, 2011
4,989
Bavaria 38E Alamitos Bay
Looking at KG's math using the PHRF time adjustment the 90 seconds translated into units of speed does not show much mathematical advantage to supporting a purchase of a folding prop.

Listening to sailors that have a folding prop they see their race time gain as more significant than the 90 second calculation from PHRF.

The accepted number is 0.5 to 1 knot.
The problem with the sailors' perceptions is that they are probably only opinions. I say this because I know how difficult it can be to measure precisely one's speed through the water (STW). I expect most sailors depend on the STW reading of their speed log although this instrument must be calibrated. Even though, one with a calibration error should still report a difference in STW between the two propellers even if absolute values were off.

A better way to get accurate comparative measurements would be to tow a flowmeter (which must also be calibrated) behind each of the yachts of the same model (stock) sailing in the same water, one with the 3-blade fixed and the other the folding. The volume passing through the flowmeter per unit time can be converted to m/s, thence knots. (This would factor out SOG effects.) But no one is going to do that:snooty:. Moreover, we know that identical one-design yachts sailing in the same water on the same day can vary significantly in VMG depending on the skipper, so you could not fully assign an observed STW difference to the effect of the different props:doh:. Thus, we're left with "gestimates."

I can't see how anyone could "accept" a number w/o some actual measurement. But maybe they are out there? Anybody shelling out minimally $3K to haul the boat and install a folding prop is gonna want to believe that a significant increase of STW will be, and is, the result. So we get a one-half to a full knot of STW increase reported b/c that is the "accepted value":liar:, when most likely it's only one tenth, maybe two (i.e., +9 sec/mile average over the fixed). But we take it on faith, baby:yeah:!
 
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Jun 15, 2012
694
BAVARIA C57 Greenport, NY
I suggest reading what Mainesail has to say about folding props.
Now my 2 cents. I do not have a folding prop. Seems to me there are better ways to spend 5 grand. Also boats are a continuous fix so I don't want something else to maintain. Perhaps if I were going to sail across the pond I might change my thinking.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
the OP asked about props. so lets talk props and how it can affect the sailing of a boat. just the sailing part, not the motoring.

1609286377984.png


this is aeolus. two bladed, fixed prop, michigan wheel "sailing prop", held in place by a brake on the shaft. this is how the alden company designed the boat to be used. racing, cruising, just sailing, this is how my boat works.

next, lets talk about the science of props on sailboats while the boat is under sail. it's very easy to test the differences and measure the differences. take a motorboat, mount a 40' pole in the bow in the middle of the pole. tie 2 J35's to each end of the pole. one with a three bladed prop. one with a folding prop. start motoring. have a scale attached to each tow line. read the drag differences at say every 1/4 knot up to say 10 knots. now you can start comparing drag differences through the whole spectrum of the the boat sailing from A to B. more considerations. does the drag of the prop affect the function of the foils, the waters drag on the hull surfaces. so, running, reaching, beating, the drag might affect the boat differently in each mode. all the foils must work well to get good VMG's. dragged water will change the rudder/ foil dynamics.

lots to consider to just 'sail your boat well'
 

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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
the J 35 class on lake michigan was rocking back in the 80's and 90's. sailing the mac race, the were like a flock of starlings. the whole race.

they became my test group. they rate around 92 phrf, i rate 159 phrf. ( they are really great boats).
i sailed my first mac set up as aeolus had always been sailed. from the 60's. .......................... damm , i was slow from start to finish.
i read bethwaite ten times that winter and started to prep aeolus to sail at or above my rating. i sailed aeolus well below my rating that first year. ........................................................................................... the biggest, one thing i changed, to get aeolus going, the biggest game changer, the prop. three bladed, prop, locked up in that aperture. to the 2 bladed sailing prop hidden in the aperture.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
unlike most of you boys, I talk about the % change while sailing from A to B. some of you talked about gaining knots or more. what? at what wind speed, at what sailing angle. that info don't mean much.
in a mac race, you'll get the full spectrum of summer conditions of weather. sailing A to B, start to finish.

with this great test group, the J35's, it became clear how different changes increased my A to B times. on aeolus, light winds, no winds, zephyrs, strong winds, fronts, runs, reaches, beats, all the sail i could get up without dying, i easily got a 5% increase in A to B speeds. that gift in racing is huge, hell, that gift in cruising/sailing aeolus is huge. it's a game changer.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
huge change in chasing those all night zephyrs.
huge change in steering the boat while flying a spinnaker DDW in a 40 knot wind.
and everything in between.

hulls, foils, water flow/friction, sails, tune, tweak, trim, .............. biggest %from any one thing? prop

on aeolus
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
if you love to sail, and you want to sail "well" read how by reading bethwaite
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
so a friend calls you up, just bought a porsche 911 S, invites you for a ride. you get in and he eases to the freeway and gets on. he drives for 3 hours going 5 MPH under the speed limit. what do you think when it's over? me, i'd think BORING!!!! i'd want a full sport ride on through the twisties up in the mountains, but that's just me.

i see sailing the same way. everyone gets to choose what they like best, and that's all good. me, i'm a sport kind of guy. i attract other sport minded people to crew for me. never short of crew.

jon:cool:
 
Dec 19, 2006
5,809
Hunter 36 Punta Gorda
I added Flex o Fold folder because first dealer put wrong prop when new and could not get over 6 knots
and this prop cheaper than most and no maintenance except keep it clean and very happy with it since
2007 improved sailing and motoring and reverse for my boat.
Nick