de havilland 5.3m

[vp3]

I am thinking about purchasing a de havilland hercules 5.3m hull does anyone have any advice as I have never seen this make before. I believe it is riveted together, is it possible to weld all the plates or are rivets sufficient. What size motor is recomended.
Any help is appreciated





Cheers Ian

[subzero]

This is all I can come up with so far Ian.
Having no personal knowledge of the pro's and con's I will keep looking
Cheers LLoyd

So, how do you know. Were can you go to get an honest appraisal of the positive or negative aspects of an aluminum boat that has a rivetted hull or a welded hull. That is all aluminum or has wooden decks and floors. I thought I had this pretty much wrapped up until I looked at the web site for my current boat and found out their Deep V I was looking at has a welded hull and wooden floors/decks.


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8/2/04 7:24:00 PM Submitted by Rivernut (24.34.190.189) from MASSACHUSETTS says welds are good, wood is bad
This is not a complicated subject. Welds make for stronger connections, rivets may come loose and leak. A wood deck is heavier than an aluminum deck. Wood will eventually rot. Less expensive boats have rivets and wood. It depends on how much you want to spend and how long you plan on owning it.


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8/3/04 9:20:00 PM Submitted by Pat K (152.163.253.33) from MINNESOTA says Aluminum boats
?"Less expensive boats have rivets"? Rivernut has never priced out a Lund or other premium riveted boats. I had an Alumacraft for 6 years and I've had a Lund for 7. Both riveted, both run hard on rivers and neither one has leaked. Riveted boats can leak, welded boats can crack next to the welds. The number of stringers, thier stregnth and placement have more to do with hull stregnth than welds or rivets.


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[subzero]

Posted by Chuck (209.131.252.116) on April 12, 2004 at 08:07:18:
In Reply to: Re: Welded vs. riveted boats? Recommendations? posted by Terry on April 12, 2004 at 06:40:38:

I too am hard on boats. I broke up a Lowe 15-ft 42-in bottom riveted flat with Johnson 25 and a PolarKraft 1652 riveted MV with a 30-hp Mariner. Both boats began failing within a few years of heavy use.

My current ALWELD 1752 Flat with a 40 Yamaha has lasted over ten years of similar abuse. Welds are begining to crack now. Some welds are failing on the front deck, and I am beginning to suspect some problems in the floor ribs. I need to pull up the floor to inspect before passing judgement here.

My opinion: Riveted for light use with a small (less than 15 horse)outboard, welded for larger boats with higher horsepower. Even here, I would stick to 40-50 hp on 0.100 gauge welded flat boats.

Additional thoughts which I have expressed here before: I am concerned about the trend towards marketing large welded high horsepower boats. One manufacturer is even selling a what is essentially a MV John with a 200 hp outboard.

One should definitely look hard at some used versions of a planned purchase before plunking down hard earned cash on your new dream boat.

Posted by Mike (66.189.200.104) on April 13, 2004 at 20:46:48:
In Reply to: Welded vs. riveted boats? Recommendations? posted by Richard on April 11, 2004 at 10:34:20:

Rivitted boats will cause more drag and have a greater chance to leak than a welded boat...BUT they are no stronger than the supports used to create the craft...I have seen countless and countless welds fracture....In fact, rivitting corners of certain light gauge boxes, gussets, etc. are much, much stronger than welds...Welds would definetly crack....Welds are not used on light gauge boats for this reason alone, not because of any other reason....How can you get superior strength from a weld that is holding .040" or .050" alum.? You cannot...If you want to believe all this hype you read from boat manufacturers selling their welded boats, you are being misled...A manufacturer sells labor..Period...When a manufacturer has switched from rivitted to welded, it is because they are selling you their robotic welding cells in which eliminates man power...I know this is fact, and some will disagree, but oh well...Learn to live with reality...

Michael J.

In Reply to: Re: Welded vs. riveted boats? Recommendations? posted by Jimmie on April 11, 2004 at 16:46:06:

I have owned many aluminum boats and have experienced long-term use with both riveted and welded. A newer riveted boat will probably not leak, you get a little more for your money, and they are fairly durable. If you're like me and you fish the sierras, you run your boat up on shore alot and maybe rub a rock a rock or two trying to get into a tight spot. After years, the rivets will loosen. It's nice to compare boat rivets to aircrafts', but the fact is that there are weight and cost issues. If a plane needed to go boat camping regularly, it would be welded. Find your purpose, then buy a boat that suits it.

Also...cracking a weld on a boat is like breaking a bike frame. It ain't that easy!

[vp3]

Thanks Lloyd for the trouble you have gone to. I'm still in the dark though
Cheers Ian

[Kerry]

The problem with comments from the States is that up until not so long ago small welded alloy boats were rare over there even though they are bread and butter here. Actually many yanks are mystified that some people actually use alloy boats in the saltwater #:o

But the Dehav Herc is from a past era (along with the 21' Trojan) when if it was good enough to fly in things that were rivited then surely it was good enough on the water.

Alloy methods and capabilities have changed considerably from when Dehav first made these styles of boats but then there wasn't much else in alloy being made then either and riviting suited the design and alloy welding really wasn't what it is today.

Welding these now, wouldn't even think about it. There's one still running around here with an old 2S 70 Johno on the back (I think) and probably wouldn't really go any bigger than that.

Cheers, Kerry.

[vp3]

Thanks for your thoughts Kerry
Cheers Ian

[joe_parry]

Yea Ian Ive got one of these, had it for about a year, got a 55 johno 2stroke on it,mines got centre console, rivets are fine in this one, leaks but most boats do, hit the bilge pump after youve been out for a few hours, big deal, I get along comfey at 25-28km by gps, youu could go to 70 horse no worries pretty clean for a tinny,have to trim motor in a followinmg sea as it will nose dive, so do most boats, this one will do me plenty of room and the price was right give me a yahoo if you want ta ask anything,theres a lot worse boats built then this, cheers joe

[vp3]

Thanks for the info Joe. The boat I was looking at had 2 bunks in a cabin on the bow. This was made of marine ply and all needed replacing. I realy think the old girl is not for me. I'll keep looking---
Thght lines, Cheers Ian

[jimbob]

G Day Ian
Mate i bought a de hav 4.5 all rivets welded by previous owner and i cant praise it enough does not leak a drop gets along great with a 40hp the only complaint is it does not have enough freeboard but for the price i payed its perfect i must admitt it looks are not great but it floats doesnt leak so what else can i ask from a boat except it could maybe attract more fish :D :D :D

[vp3]

Thanks for the reply Jimbob. I'm glad you are so happy with your de havilland.I can't imagine how long it would take to weld all the rivets in the hull of the 5.3m, theres at least a thousand. Each one could possibly leak in a boat of this age. It would have to be labor of love to weld each one something I don't have, I'd rather be fishing.
Tight lines Cheers Ian