Major modifications to a 31' Silverton

Discussion in 'Boatbuilding' started by Stan, Mar 15, 2002.

  1. Stan
    Joined: Mar 2002
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    Location: West Chester pa

    Stan New Member

    I'm considering serious modifications to my 1981 31' Silverton gulfstream (express cruiser). First, the old 350 crusaders face aft and use walter v drives with borg warner trans to power the boat. I'd like to re-orient a pair of diesels to face forward so that its a direct drive setup (amidship). To do this, after removing the old engines, the 250 gal fuel tank and the bulkhead that supports the tank needs removed. this opens up enough space to place the diesels forward. Next, I have to cut openings in the deck large enough to drop the new engines in. I'd try to use the existing 250 gal tank and place it where the old engines were located. Some other modifications include pluging up the water drains on deck and cutting scuppers thru the aft gunnles.

    My question is, how stupid am I? :p More importantly, What do any of you know about the design and construction of Silverton boats of this vintage? My observation, after a survey 3years ago, is that the hull is solid. Also, after running off shore with her, I am pleased with the deadrise deep-v design that cuts thru 3-4 footers with relative ease. The planing hull bottom is nearly 3in thick and is balsa cored. She's approx 12,000 lbs and feels like a heavy, sturdy boat which is what i want. Some flaws come to mind like the hull to deck joint. Silverton really cut corners here. THe v-drive setup puts an enormous amount of weight in the rear of the boat. it takes 18" x 12" trim tabs to keep her nose down - imagine what happens when the trim tabs fail. Thus the reason why I want the new motors amidship. When taking on 3 plus footers, water spays over the bow. I'd like to remedy this by adding a strake along the bow. Has anyone done anything like this above?

    I realize there is no resale value in this. but to purchase a boat of similar design is over the $100,000.00 mark. Many new boats are made of the "yet untested" foam core. To me, the heavier the better and the deeper the V the better. Diesels are costly but within budget. Rather than buy new, which is unaffordable and undesirable, I just assume build my own. Thoughts, experiences comments are welome. Much of my opinions on boats comes from David Pescoe's website
  2. Guest

    Guest Guest

    silverton re-build

    dont waste your time buddy, you cant paint a turd, save your money and get yourself a new boat! better yet, use the money to fix up your house, something that might bring a little bit of resale value, like a new deck or a fancy ep henry walkway. Get the old man to provide the boat, let him worry about the repairs. That way when you go to the beach for the weekend, all you have to bring is your cooler and bait, leave the toolbox at home. Furthermore, its going to be a pain in the a$$ to drag those tools back and forth from the broken boat in cape may to the broken truck in west chester. love always, smart woman
  3. Guest

    Guest Guest

  4. Jeff
    Joined: Jun 2001
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    Location: Great Lakes

    Jeff Moderator

    What? Someone on our forums who advocates putting money into a house instead of a boat??? What has happened - has the Earth shifted out of orbit?

    Seriously, there are more important things than money, and if you love your boat, that boat, and look at it in terms other than resale value, there's nothing wrong with putting some time and money into making it a little better. I have lots of fond memories of all the time I spent working with an arm contorted reaching under the engine blocks in my second boat to fix this and that which kept breaking. Not much resale value, but a lot of memories. I'll probably put some more money into it soon too :)
  5. Stan
    Joined: Mar 2002
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    Location: West Chester pa

    Stan New Member

    UMMMM, Honey don't worry! I'll get the deck done for ya. Didn't you read the last paragraph about how much money i'd save if i didn't buy a new boat and just fixed up the old one? It won't cost us that much to do some minor altercations. Besides, I was going to fix up the cabin with new upolstry and cabinets just for you too!

    Dammit, I wish my wife didn't catch me writting these things! I get caught every time.
  6. Jeff
    Joined: Jun 2001
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    Location: Great Lakes

    Jeff Moderator

    Laughing out loud :)
  7. Stan
    Joined: Mar 2002
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    Location: West Chester pa

    Stan New Member

    The inquiry about modifying my silverton is on the board here if someone wants to take a stab at it. I'd like to here from you folks who have experience in this stuff. Despite my wife and having "issues" about the project, I'd still like to get your input.

    I'm sure you all can relate to balancing a limited budget between what is needed and important for a young family and still having the desire to pursue boating.

    So how about it? any takers?
  8. Unregistered

    Unregistered Guest

    31 silverton ,diesels suck/stink/ too slow/vibrate

    factory diesel silvertons have thicker stringers (lots of torque)and larger air intakes
    hard to believe you get spray from a silverton lighten up on the tabs dude and get her on a real plane 25mph minimum about 3400rpm(nancy)

    their is a slight curverture at the rear of the hull witch keeps the nose down/works much better when thier is'nt20 years of paint on the bottom

    not a big boat a bit of extra chain on your anchor rode will make a difference/heavier anchor

    what you need are big blocks better mileage,more speed i have 31 convertable the ride is better at speed 30mph whole new animal
  9. Corpus Skipper
    Joined: Oct 2003
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    Location: Corpus Christi TX

    Corpus Skipper Hopeless Boataholic

    I've seen plenty of 20 plus year old Silvertons around, fit and finish is crummy, but a stout hull, and I've never seen one blister. You like the ride of this boat, which is a great thing, as far as the spray, rails will probably do no good on the bow. My Chris has a major reverse chine which works great, as long as the wind ain't blowing :D still get sprayed on the bridge when it's bumpy, and plenty across the bow. I feel your pain with the trim tabs also, but unless you want to beat your boat apart at 30 knots, they're a necessary evil. Anyway, if you love your boat, do it!!! Mine is the same, won't have any resale value, but I love the boat, so what the h#&@!!!(and I can't afford the 100K replacement either) :(
  10. jprev
    Joined: May 2003
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    Location: Florida

    jprev Junior Member

    You are not stupid...

    You just have way too much time on your hands...

    :cool: Just kidding...

    You just should buy a new/used boat with the configuration you desire and save yourself a lot of time and probably a lot of money. Of course it's rumored that some people just like working on boats...


  11. jimcorliss
    Joined: Mar 2004
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    Location: Downeast Maine (Columbia)

    jimcorliss Junior Member

    I have the same boat in a 1979 model. Great Boat ! I was considering a single engine and placing a full keel. (The P-struts like to snag lobster trap lines here in Maine). As it is I'm building a lobster boat up from the hull instead. I still had the pleasure of building a keel and it wasn't too difficult. (not on the Silverton... I'll probably sell it when the lobster boats finished this summer). I hope that your new engine plan doesn't take away from the huge living space you now have.... one benefit of the reverse gears is to get the engines in the rear and free up more room in the cabin. Will the engines be low enough ?

  12. Woody65
    Joined: Sep 2012
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    Location: Cobconk

    Woody65 New Member

    1981 Silverton

    Hi Folks,

    I'm a newbe here...and have a question...I'm looking at a 1981 Silverton Gulf Stream for a family crusier. I have to reaarange the sofa into a chrtis craft bunk style.

    I read some negitive feedback on this boat. Are they a good boat??
    The one I'm looking at is clean and has 800 hours on it.

    Can you advise.

    Thanks Paul
  13. paulfish
    Joined: Sep 2012
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    Location: new york

    paulfish paulfish

    Stan O, Go for it! Nothing like doing a refit on a boat,it's a labor of love.12,000lbs. on a 31' makes it a brick and the hull is sound. Go with the diesels. You'll sacrifice speed but you get reliable in return. Diesels last longer,are more fuel efficient and no explosve fumes as with gas. Jeff O is right, why spend money on a house when you can spend it on a boat. Really no getting around the spray problem except with the tabs. Try experimenting with the tab angle as you run and adjust to keep the hull efficient with some combination of RPM and KPH. Tabs can make a big difference as you know and of course move whatever weight forward that you can. Good luck.

  14. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    Woody, I find it easier to post here rather than PM you on that Silverton. You might consider posting a new thread regarding your potential Silverton purchase. I deleted the post I made yesterday as I was responding to the original post that was stale. I hadn't noticed the date of the original post.

    While it's true that I've been restoring my '73 for some time now, I'm by no means an expert on Silvertons. I don't know if there really can be such a person as the company has changed ownership over the years and the design and manufacture of boats varies from model to model and year to year. I believe that in older boats especially it can vary from boat to boat as well, even if they are the same model.

    The comments below relate to my '73 sedan and might be applicable to an '81 express, then again they might not. Keeping that in mind here are a few observations.

    As many have stated the older Silvertons had stout hulls but the fit and finish was not all that great. I'd agree with that statement and can tell you that my old hull has absolutely no signs of blisters. The remainder of the boat (with the exception of a fiberglass tub that forms the rear cockpit) was fabricated from marine plywood and mahogany.

    The major issues that I found were:

    1. Insufficient wet out and tabbing of stringers and floors. In some areas there was raw fiberglass visible that had never been wet out. This caused water to infiltrate the stringer or floor and rot it out over time.

    2. The roof support pillars that formed the windshield on this boat were not heavy enough to do the job.

    3. The fore/aft beams supporting the side decks at the cabin walls were inadequate and made of southern yellow pine. It failed and allowed water to infiltrate the side decks and cabin sides. Caused all sorts of problems.

    4. The factory supplied flybridge was of molded glass and gelcoated. It was the most uncomfortable thing I ever saw. Perhaps it was an add-on or afterthought. I had to design my own.

    I noticed that the design of the boat was generally well thought out. Lots of room for her size, wide side decks (don't feel like I'm going to fall off) and dual stations in a small package. BUT, in 1973 I don't think that the manufacturer had good sealants (like Sika or 3m and epoxies) and good techniques to prevent water infiltration. Actually, most of my boat had no sealants used at all. Today we do, but even so it seems like many production boats are assembled as quickly as possible and corners are cut. This isn't necessarily a criticism. If a manufacturer put as much time and effort (and materials) into production boats as a lot of people here do with their projects, they would be unaffordable.

    So look closely, get a survey and be ready to spend some money on repairs and updates. Remember, if this boat costs $10K and a comparable new boat costs $150K, you are going to be spending some "$K's" keeping the older boat running.

    Maybe not the whole $140K difference, but.....

    There is no such thing as a free lunch
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