Is this a Planning, Displacement, or Combination Hull

Good advice, and the way I am leaning; more and more every day in fact. I'll simply drag the runabout behind her and use that for speed thrills after this boat is at anchor.

Any guess as to what speed I should shoot for, and what hp rating I would need to achieve that speed? Displacement speed and hp calculations seem very straightforward, but what of semi-displacement calculations?

The current 4-53's are shot - and getting the next set of engines picked correctly is important to me so that I can move forward with the boats more pressing needs.

 

The boat in your post #1 is not the boat in your post #27 (Zanzibar yacht: http://classicyacht.org/boats/zanzibar). So which boat are we discussing?

 

Good advice, but it sort of defeats the purpose of buying the boat. I wanted a platform I could learn on. Not that I expected to become a marine architect while restoring her, but this subject of repowering seems entirely too interesting to farm out 100%.

One thing I will definitely farm out is the calculations for correct placement of the engines with regard to weigh and balance and their effect on hull stability.

I guess I just want to be able to talk with the marine architect somewhat intelligently about the project. If I just wanted to hand over the money and say "fix it" - I would have never have bought this boat. I would have simply handed over my money up front for a boat without these problems It's been my experience that it is always cheaper to buy something done proper in the first place than to buy a disaster and then fix it yourself; unless fixing it yourself is was the goal in buying it of course.

 

The boat in post number 1 is the Andy Bell. That's my boat.

The boat in post #27 is Zanzibar, as you noted.

Zanzibar and Andy Bell are almost identical with the exception of the sterns. I know that after having done some research using Haggin museum which is the organization that received all the Stephens Brothers records after they closed down.

I do not have any pictures of the Andy Bell's bottom, but I did find that picture of the Zanzibar's bottom - so I put that up in hopes that the better picture would help us confirm the type of hull the two boats had.

 

The speed and power estimates are highly dependant on the hull shape, dimensions and weight. In the fast-displacement speed range the weight and the distribution of masses are two very important parameters which determine the max speed for a given power. Since the transom of your boat is so radically different from the other one, how can you be sure that other important measures are comparable? Hence, I would be very cautious with direct correlating of powering data between the two models.
Once again I second PAR's advice that you need a professional help here. A person who will climb on board, take the necessary measurements, perform sea trials and give you the answers you need. All the rest is just a more or less educated guesswork. You will ask 10 persons about their opinion and will get 10 different answers...

 

Thanks Daiquiri,

I have requested the hull drawings from the museum and they appear to have the originals. Would it be safe to say that they did a good job of placing the engines back in 1948 (the original 6-71's, not the repower 4-53's)? Or do we know more about such things now and are hence able to do a better of engine placement then the builders could back in 1948? I ask becuase more and more it looks like I am going to simply re-install the original engines, and if so why not put them in the original positions and leave it at that. Stephen's Brothers appears to have had a good reputation, so I am assuming that they did the job correctly back in 1948.

As for hiring an expert I agree that this is what should be done if I make any changes - or even keep the current 4-53's which may or may not have been placed correctly during the repower. Is there a professional society of marine architects that one consults when looking for such help?

 

Anyways, this guy claims 10 kts cruise and 14 kts max speed with 160 hp total power:
http://www.boats.com/boat-details/Stephens-RAISED-DECK/152665461#.UtWtj9Kk-So
For what it's worth as a first guestimate.

 

I guess there is... But I am in Italy, so you better ask our american friends here.

However, there are several well-reputed professionals in this forum too - Eric Sponberg (http://www.boatdesign.net/forums/profile/eric-sponberg.html) and Paul Riccelli a.k.a. PAR (http://www.boatdesign.net/forums/profile/par.html) being the first two which come to my mind. If you're much more towards the north, than you could contact Tad Roberts (http://www.boatdesign.net/forums/profile/tad.html).

Cheers

 

Seeing he paid next to nothing for this old girl, the first item of business should be a thorough professional survey to establish the overall soundness of it, before even thinking about new engines. You don't plonk expensive machinery in a boat that has, maybe, dire structural problems, you either fix those problems, or decide they are too expensive to remedy, first. It would be pretty remarkable if there weren't substantial issues in a timber vessel this age, especially considering it was sold at a "bargain" price.

 

Yes true. 100% true. That survey will occur when she comes out of the water next month. However, that would also be a good time to do whatever I need to do with the engines IF I HAVE ENOUGH FUNDS left over to do it.

OR

I could forget about new/any engines for now, have the yard pull the current engines out when they have her up on the hard, and worry about new engines the next time she comes out. Realistically she is a five year project so why the rush to hear engines running so soon right??? Emotional I guess!

In any event thank you all for your advice. It has really saved me a lot of money already versus my original plan.

Leo

 

Post to ongoing build thread. Thanks for the help

I just wanted to thank everyone for their great input. If you would like to follow the restoration of the boat we have been discussing here this is the link to her ongoing build thread.

http://forum.woodenboat.com/showthread.php?172230-Restoring-a-1948-Stephens-Motor-Yacht

Again, thanks for taking the time to share your knowledge with me.

Cheers,

Leo