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Old 11-10-2013, 11:04 AM   #621
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Hendo I'm kinda surprised at your "Marlin Board". I'd call it more of a hull extension myself but hey you're in OZ.

You're doing something similar to what Gulfstar did. Extend the stern and leave the prop and rudder where they were. A stern extension is almost always better than a big swim step. In you're case it wouldn't take much effort to extend the prop shaft and install an appropriate "V" strut. For that matter moving the rudder aft is something you could do after dinner and only miss your favorite news program. You would have even more prop clearance and possibly open the door for a larger prop but I like the one you have. But moving the prop and rudder aft I'm quite sure will be a good thing. Need to get it all lined up well though.
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Old 11-23-2013, 11:21 AM   #622
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Hendo I'm kinda surprised at your "Marlin Board". I'd call it more of a hull extension myself but hey you're in OZ. You're doing something similar to what Gulfstar did. Extend the stern and leave the prop and rudder where they were. A stern extension is almost always better than a big swim step. In you're case it wouldn't take much effort to extend the prop shaft and install an appropriate "V" strut. For that matter moving the rudder aft is something you could do after dinner and only miss your favorite news program. You would have even more prop clearance and possibly open the door for a larger prop but I like the one you have. But moving the prop and rudder aft I'm quite sure will be a good thing. Need to get it all lined up well though.

Thanks for your reply Eric. Yeah look I just called it a Marlin Board mate, with no real basis of reason other than that's what I was reading about at the time and was looking at building before I got carried away and built what I built but I agree with your naming Being more like a hull extension.

The topic of prop shaft extension has popped up a few times in my time here. Can you help me understand how that would work please mate cause I'm struggling work out how I could do that without changing a whole heap of things. I've been looking at her and if i move the prop to far aft then she'll swing below the keel. I've also noticed that the rudder can only be adjusted so far without interfering with the seals. Not saying I couldn't cut and weld a shaft extension on the rudder stock to overcome that but that's something I was about.


If I move the whole unit aft to keep the clearance between the screw an rudder then the keel tunnel will be on the piss and need to be changed to ensure the shaft is straight.

Thanks to AXE's supporters and followers on here, I found out about the min clearance relationship between screw and hull thus ultimately saving my arse. Is there a similar relationship between the rudder and screw? Could the rudder move aft counteracting any drag the hull extension would make but leave the screw where she currently is? I then would be looking at having to enlarge the rudder because the water force passing over it from the screw would be less do to the increased spacing wouldn't i?

Not sure if the time and cost would be worth any change? What's your thoughts?

Appreciate your advice and help mate. Cheers
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Old 11-23-2013, 12:07 PM   #623
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A lot to swallow mate.

Rudder aft of normal will decrease the propwash over it but increase the leverage it has on the hull. May not need a bidder rudder. Depends on several things. Was it big enough in the first place ect ect. In the other direction if the rudder istoo close to the prop I'm sure you will feel more vibration and yes I do think there is a rule of thumb for this.

A prop further fwd would/may have an advantage of not coming out of the water in heavy going. Also prop walk would be slightly reduced.

I'll get back later about the shaft extension.
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Old 11-23-2013, 02:37 PM   #624
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It's not even noon yet and the edit feature is off. Used to stay on for days and on BD.net I think it never goes off.

You can extend a shaft w couplings. I prefer the long couplings that don't have a flange. One must be ready to install intermediate bearings if needed. There are standards set forth that dictate how much unsupported shaft is OK w a given dia. shaft. If you're at the limit you'll need to install an additional shaft bearing. When it's all done and the boat has been in the water a few days all bearings need to be in alignment and the engine aligned to the shaft. This means room for radial adjustment on intermediate bearings should be provided.

If your propeller swing needs more room re the keel shoe from moving the shaft aft just install a new shoe attached to the bottom of the keel. This should give you the added clearance of the thickness of the old shoe. Rudder shaft may need to be extended also.

Remembering the pics of the past you probably should consider a V strut just ahead of the propeller ... 4" approx.

I think making your boat longer is a very good idea.
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Old 11-23-2013, 08:58 PM   #625
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Thanks mate
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Old 11-24-2013, 04:00 PM   #626
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Thanks mate
years ago I delivered new Vikings and they made a 44 ft motor yacht, then they took the same mold and made it into a 50 ft motor yacht, they added 6 ft to the hull,the 50 ran faster with they same engines as the 44 and they left the shafts and rudder in the same place that they were on the 44, the 50 ran nice and flat,may be the 6 ft gave it more lift,but the boat ran 4knts faster
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Old 11-24-2013, 04:34 PM   #627
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years ago I delivered new Vikings and they made a 44 ft motor yacht, then they took the same mold and made it into a 50 ft motor yacht, they added 6 ft to the hull,the 50 ran faster with they same engines as the 44 and they left the shafts and rudder in the same place that they were on the 44, the 50 ran nice and flat,may be the 6 ft gave it more lift,but the boat ran 4knts faster
WOW! That's interesting...

6' longer boat than the 44'er (with well over 10% length increase, did beam remain same?) - therefore carrying considerably more weight - using same engines and leaving shafts/rudders in same location as the 6' shorter 44’ version... but the 6' longer 50'er attained 4 knots added speed... I'd love to read sea test spec sheets on both... you have access to any?

Was the 6' length addition to stern only - or disbursed in areas?? If 6’ addition was gained only by lengthened stern... it would be a long swim to props if buoy line became tangled! And, lift operators of sling hoists would be pretty surprised unless there were sling-placement instructions/arrows clearly posted on hull/gunnels.
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Old 12-01-2013, 05:15 AM   #628
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Lift operators of sling hoists would be pretty surprised unless there were sling-placement instructions/arrows clearly posted on hull/gunnels.
Good point od mate i'll have to remember that when the time comes ... Cheers
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Old 12-01-2013, 07:02 AM   #629
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Quote:
Originally Posted by capt jerry View Post
years ago I delivered new Vikings and they made a 44 ft motor yacht, then they took the same mold and made it into a 50 ft motor yacht, they added 6 ft to the hull,the 50 ran faster with they same engines as the 44 and they left the shafts and rudder in the same place that they were on the 44, the 50 ran nice and flat,may be the 6 ft gave it more lift,but the boat ran 4knts faster
I think I'm right in saying the extra speed would have come almost exclusively from the added waterline length alone. Remember the old formula, speed in kn = 1.34 X sq root of waterline length in feet..?
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Old 12-06-2013, 01:44 AM   #630
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I think I'm right in saying the extra speed would have come almost exclusively from the added waterline length alone. Remember the old formula, speed in kn = 1.34 X sq root of waterline length in feet..?
My head hurts just thinking about working that out.
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Old 12-06-2013, 02:19 AM   #631
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To save me wading through 600 posts I'll ask the question here...WHY?

Wouldn't it be cheaper and easier to start from scratch or just buy one ready to go?

Dont get me wrong, I takes me hat off to you for doing it but I also shakes me head at the same time.
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Old 12-06-2013, 02:23 AM   #632
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years ago I delivered new Vikings and they made a 44 ft motor yacht, then they took the same mold and made it into a 50 ft motor yacht, they added 6 ft to the hull,the 50 ran faster with they same engines as the 44 and they left the shafts and rudder in the same place that they were on the 44, the 50 ran nice and flat,may be the 6 ft gave it more lift,but the boat ran 4knts faster
Pretty common on sailing boats especially cats.
One of the most common of performance enhancers besides getting rid of excess weight and a clean bottom is to add some length.
Added bonus is somewhere nice to swim from, bring a dinghy into and retrieve a MOB.
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Old 12-06-2013, 05:34 AM   #633
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To save me wading through 600 posts I'll ask the question here...WHY? Wouldn't it be cheaper and easier to start from scratch or just buy one ready to go? Dont get me wrong, I takes me hat off to you for doing it but I also shakes me head at the same time.
Thanks for your questions but If you have to ask why then you won't understand the reason but to answer, Yes. It would be easier to buy one already done.
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Old 12-06-2013, 06:11 AM   #634
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Thanks for your questions but If you have to ask why then you won't understand the reason
Wont I?
I am a shipwright by trade if that helps.
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Old 12-06-2013, 10:38 AM   #635
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Wont I?
I am a shipwright by trade if that helps.
Dear Parmenter

I’m confident Matt has by far and away the best answer to your (shipwright background) experience filled reasoning for your specific inquiry of “WHY?” on post# 631...

However, after becoming friends with him during his arduous and per-item-expeditious very fulfilling long term task of restoring AXE from the ground (err, water LOL) up, and, having followed his every post as well as reading every post from other TF members aimed toward his assistance... I would like to place the following answer of mine to your (post # 631) question of ”WHY?”. BTW – If you do take time to review all posts in this monumental thread you would see that Matt and his gal are well in tune together on this project (that’s called bonding) as well as the clear fact that it is in Matt’s nature to successfully take on intense projects of product beautification and restoration with wonderful outcomes at their conclusion. No matter what type of a project for restoration I were to ever undertake it is Matt who I would hire to assist... so I could then feel confident of successful conclusion to my endeavor. The man has pit bull like capability of never letting go of an object with the muscle power of a Rhino backed by keen mechanical intuition and the mental energy to see things through. Yeah - - > I, and I’m sure also are many others on TF, am damned well impressed by Matt’s fortitude and sheer desire to successfully complete his every project – especially on AXE. And, in addition, during this long and well documented re-build journey it is resoundingly obvious that he is one hell of a “Cool Cat” who can take the winds of time in stride – always coming to the top wherever/whenever that level in needed!

Soooo... If I may be so bold... here’s my answer to your question of “WHY”?.

Because he is driven by an intense internal desire to perfect material product projects. And, very importantly... simply cause he wants to work his refurbishment magic in a previously (to him) untested field of wooden, large-cruiser-boat, marine goods! Also, importantly, because AXE’s successful conclusion will become another documented notch in his product restoration belt! Not to mention the fun he and his Admiral and family and friends will have on AXE once her restoration is substantially attained and she gets splashed.

Please understand: With you as an experienced shipwright who spent years in your trade and me as a person who spent a couple decades working alongside shipwrights in mid 20th Century restoring, refurbishing, adding onto, and building wood as well as fiberglass boats anew in New England – well – we simply do not have the same fire in our bellies as Matt has for wanting to undertake a huge wood boat restoration project – i.e., The AXE! Because, basically, you and I have “been there done that”... but, for me, never as fully as Matt is doing the AXE!

There you have it! My reasoning WHY Matt is doing the AXE – Up Round!

Matt – my friend... Hope I didn’t over step my bounds for saying what I truly feel about you and your AXE project and hope what I feel/said is somewhat correct in your eyes. I defer to you for further explanation to Parmenter.

As always I give you my Sincere Thumps Up! –

Happy Boating Daze! – Art
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Old 12-06-2013, 10:50 AM   #636
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Greetings,
Mr. P. To answer your question of "Why" from my perspective and opinion of Mr. Hendo and defering to Mr. Art's essay, I would say simply....Because it's there mate.
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Old 12-06-2013, 10:57 AM   #637
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Wont I?
I am a shipwright by trade if that helps.

That only helps explain why you don't think his project is worth the time and effort.

It isn't the destination, it's the voyage.
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Old 12-07-2013, 12:23 AM   #638
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Rick B, that's all of this site in a nutshell.
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Old 12-07-2013, 12:32 AM   #639
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I would say simply....Because it's there mate.
And that my friend is an answer I can well understand having done similarly crazy things myself and I say that with no offence intended.

To the other answers, thanks as well
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Old 12-07-2013, 12:36 AM   #640
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It isn't the destination, it's the voyage.
Having done this for a large part of my life I can say with absolute conviction that I have been on some pretty shitty voyages and am in no screaming rush to repeat them BUT, the first couple are always an adventure.

Have fun with it Matt
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